Merge pull request #496 from infosiftr/functionalization

Functionalize the entrypoint to allow outside sourcing for extreme customizing of startup

10/alpine/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec su-exec postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec su-exec postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

10/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

11/alpine/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec su-exec postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec su-exec postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

11/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

12/alpine/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec su-exec postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec su-exec postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

12/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

9.4/alpine/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_XLOGDIR"
-		chown -R postgres "$POSTGRES_INITDB_XLOGDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_XLOGDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_XLOGDIR"
 	fi
 
-	exec su-exec postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --xlogdir $POSTGRES_INITDB_XLOGDIR"
+		set -- --xlogdir "$POSTGRES_INITDB_XLOGDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec su-exec postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

9.4/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_XLOGDIR"
-		chown -R postgres "$POSTGRES_INITDB_XLOGDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_XLOGDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_XLOGDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --xlogdir $POSTGRES_INITDB_XLOGDIR"
+		set -- --xlogdir "$POSTGRES_INITDB_XLOGDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

9.5/alpine/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_XLOGDIR"
-		chown -R postgres "$POSTGRES_INITDB_XLOGDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_XLOGDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_XLOGDIR"
 	fi
 
-	exec su-exec postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --xlogdir $POSTGRES_INITDB_XLOGDIR"
+		set -- --xlogdir "$POSTGRES_INITDB_XLOGDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec su-exec postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

9.5/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_XLOGDIR"
-		chown -R postgres "$POSTGRES_INITDB_XLOGDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_XLOGDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_XLOGDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --xlogdir $POSTGRES_INITDB_XLOGDIR"
+		set -- --xlogdir "$POSTGRES_INITDB_XLOGDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

9.6/alpine/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_XLOGDIR"
-		chown -R postgres "$POSTGRES_INITDB_XLOGDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_XLOGDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_XLOGDIR"
 	fi
 
-	exec su-exec postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --xlogdir $POSTGRES_INITDB_XLOGDIR"
+		set -- --xlogdir "$POSTGRES_INITDB_XLOGDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec su-exec postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

9.6/docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_XLOGDIR"
-		chown -R postgres "$POSTGRES_INITDB_XLOGDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_XLOGDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_XLOGDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_XLOGDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --xlogdir $POSTGRES_INITDB_XLOGDIR"
+		set -- --xlogdir "$POSTGRES_INITDB_XLOGDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi

docker-entrypoint.sh

@@ -24,37 +24,46 @@ file_env() {
 	unset "$fileVar"
 }
 
-if [ "${1:0:1}" = '-' ]; then
+# check to see if this file is being run or sourced from another script
-	set -- postgres "$@"
+_is_sourced() {
-fi
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
+# used to create initial posgres directories and if run as root, ensure ownership to the "postgres" user
+docker_create_db_directories() {
+	local user; user="$(id -u)"
 
-# allow the container to be started with `--user`
-if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
 	mkdir -p "$PGDATA"
-	chown -R postgres "$PGDATA"
 	chmod 700 "$PGDATA"
 
-	mkdir -p /var/run/postgresql
+	# ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
-	chown -R postgres /var/run/postgresql
+	mkdir -p /var/run/postgresql || :
-	chmod 775 /var/run/postgresql
+	chmod 775 /var/run/postgresql || :
 
-	# Create the transaction log directory before initdb is run (below) so the directory is owned by the correct user
+	# Create the transaction log directory before initdb is run so the directory is owned by the correct user
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
 		mkdir -p "$POSTGRES_INITDB_WALDIR"
-		chown -R postgres "$POSTGRES_INITDB_WALDIR"
+		if [ "$user" = '0' ]; then
+			find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
+		fi
 		chmod 700 "$POSTGRES_INITDB_WALDIR"
 	fi
 
-	exec gosu postgres "$BASH_SOURCE" "$@"
+	# allow the container to be started with `--user`
-fi
+	if [ "$user" = '0' ]; then
+		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
+		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
+	fi
+}
 
-if [ "$1" = 'postgres' ]; then
+# initialize empty PGDATA directory with new database via 'initdb'
-	mkdir -p "$PGDATA"
+# arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
-	chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
+# `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
-	chmod 700 "$PGDATA" 2>/dev/null || :
+# this is also where the database user is created, specified by `POSTGRES_USER` env
-
+docker_init_database_dir() {
-	# look specifically for PG_VERSION, as it is expected in the DB dir
-	if [ ! -s "$PGDATA/PG_VERSION" ]; then
 	# "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
 	# see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
 	if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
@@ -65,26 +74,23 @@ if [ "$1" = 'postgres' ]; then
 		echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
 	fi
 
-		file_env 'POSTGRES_USER' 'postgres'
-		file_env 'POSTGRES_PASSWORD'
-
-		file_env 'POSTGRES_INITDB_ARGS'
 	if [ "$POSTGRES_INITDB_WALDIR" ]; then
-			export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
+		set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
 	fi
-		eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"
+
+	eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
 
 	# unset/cleanup "nss_wrapper" bits
 	if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
 		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
 		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
 	fi
+}
 
+# print large warning if POSTGRES_PASSWORD is empty
+docker_verify_minimum_env() {
 	# check password first so we can output the warning before postgres
 	# messes it up
-		if [ -n "$POSTGRES_PASSWORD" ]; then
-			authMethod=md5
-
 	if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
 		cat >&2 <<-'EOWARN'
 
@@ -97,7 +103,7 @@ if [ "$1" = 'postgres' ]; then
 
 		EOWARN
 	fi
-		else
+	if [ -z "$POSTGRES_PASSWORD" ]; then
 		# The - option suppresses leading tabs but *not* spaces. :)
 		cat >&2 <<-'EOWARN'
 			****************************************************
@@ -113,36 +119,19 @@ if [ "$1" = 'postgres' ]; then
 			****************************************************
 		EOWARN
 
-			authMethod=trust
 	fi
+}
 
-		{
+# usage: docker_process_init_files [file [file [...]]]
-			echo
+#    ie: docker_process_init_files /always-initdb.d/*
-			echo "host all all all $authMethod"
+# process initializer files, based on file extensions and permissions
-		} >> "$PGDATA/pg_hba.conf"
+docker_process_init_files() {
-
+	# psql here for backwards compatiblilty "${psql[@]}"
-		# internal start of server in order to allow set-up using psql-client
+	psql=( docker_process_sql )
-		# does not listen on external TCP/IP and waits until start finishes
-		PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" \
-			-o "-c listen_addresses=''" \
-			-w start
-
-		file_env 'POSTGRES_DB' "$POSTGRES_USER"
-
-		export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
-		psql=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
-
-		if [ "$POSTGRES_DB" != 'postgres' ]; then
-			"${psql[@]}" --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
-				CREATE DATABASE :"db" ;
-			EOSQL
-			echo
-		fi
-		psql+=( --dbname "$POSTGRES_DB" )
 
 	echo
-		for f in /docker-entrypoint-initdb.d/*; do
+	local f
+	for f; do
 		case "$f" in
 			*.sh)
 				# https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
@@ -155,22 +144,133 @@ if [ "$1" = 'postgres' ]; then
 					. "$f"
 				fi
 				;;
-				*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
+			*.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
-				*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
+			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
 			*)        echo "$0: ignoring $f" ;;
 		esac
 		echo
 	done
+}
 
+# Execute sql script, passed via stdin (or -f flag of pqsl)
+# usage: docker_process_sql [psql-cli-args]
+#    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
+#    ie: docker_process_sql -f my-file.sql
+#    ie: docker_process_sql <my-file.sql
+docker_process_sql() {
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
+	if [ -n "$POSTGRES_DB" ]; then
+		query_runner+=( --dbname "$POSTGRES_DB" )
+	fi
+
+	"${query_runner[@]}" "$@"
+}
+
+# create initial database
+# uses environment variables for input: POSTGRES_DB
+docker_setup_db() {
+	if [ "$POSTGRES_DB" != 'postgres' ]; then
+		POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
+			CREATE DATABASE :"db" ;
+		EOSQL
+		echo
+	fi
+}
+
+# Loads various settings that are used elsewhere in the script
+# This should be called before any other functions
+docker_setup_env() {
+	file_env 'POSTGRES_PASSWORD'
+
+	file_env 'POSTGRES_USER' 'postgres'
+	file_env 'POSTGRES_DB' "$POSTGRES_USER"
+	file_env 'POSTGRES_INITDB_ARGS'
+
+	declare -g DATABASE_ALREADY_EXISTS
+	# look specifically for PG_VERSION, as it is expected in the DB dir
+	if [ -s "$PGDATA/PG_VERSION" ]; then
+		DATABASE_ALREADY_EXISTS='true'
+	fi
+}
+
+# append md5 or trust auth to pg_hba.conf based on existence of POSTGRES_PASSWORD
+pg_setup_hba_conf() {
+	local authMethod='md5'
+	if [ -z "$POSTGRES_PASSWORD" ]; then
+		authMethod='trust'
+	fi
+
+	{
+		echo
+		echo "host all all all $authMethod"
+	} >> "$PGDATA/pg_hba.conf"
+}
+
+# start socket-only postgresql server for setting up or running scripts
+# all arguments will be passed along as arguments to `postgres` (via pg_ctl)
+docker_temp_server_start() {
+	if [ "$1" = 'postgres' ]; then
+		shift
+	fi
+	# internal start of server in order to allow setup using psql client
+	# does not listen on external TCP/IP and waits until start finishes (can be overridden via args)
 	PGUSER="${PGUSER:-$POSTGRES_USER}" \
-		pg_ctl -D "$PGDATA" -m fast -w stop
+	pg_ctl -D "$PGDATA" \
+		-o "-c listen_addresses='' $([ "$#" -gt 0 ] && printf '%q ' "$@")" \
+		-w start
+}
 
+# stop postgresql server after done setting up user and running scripts
+docker_temp_server_stop() {
+	PGUSER="${PGUSER:-postgres}" \
+	pg_ctl -D "$PGDATA" -m fast -w stop
+}
+
+_main() {
+	# if first arg looks like a flag, assume we want to run postgres server
+	if [ "${1:0:1}" = '-' ]; then
+		set -- postgres "$@"
+	fi
+
+	if [ "$1" = 'postgres' ]; then
+		docker_setup_env
+		# setup data directories and permissions (when run as root)
+		docker_create_db_directories
+		if [ "$(id -u)" = '0' ]; then
+			# then restart script as postgres user
+			exec gosu postgres "$BASH_SOURCE" "$@"
+		fi
+
+		# only run initialization on an empty data directory
+		if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+			docker_verify_minimum_env
+			docker_init_database_dir
+			pg_setup_hba_conf
+
+			# PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
+			# e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
+			export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
+			docker_temp_server_start "$@"
+
+			docker_setup_db
+			docker_process_init_files /docker-entrypoint-initdb.d/*
+
+			docker_temp_server_stop
 			unset PGPASSWORD
 
 			echo
 			echo 'PostgreSQL init process complete; ready for start up.'
 			echo
+		else
+			echo
+			echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
+			echo
+		fi
 	fi
-fi
 
-exec "$@"
+	exec "$@"
+}
+
+if ! _is_sourced; then
+	_main "$@"
+fi