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postgres/src/bin/pg_rewind/t/RewindTest.pm
2019-09-30 14:04:00 -03:00

329 lines
8.5 KiB
Perl

package RewindTest;
# Test driver for pg_rewind. Each test consists of a cycle where a new cluster
# is first created with initdb, and a streaming replication standby is set up
# to follow the master. Then the master is shut down and the standby is
# promoted, and finally pg_rewind is used to rewind the old master, using the
# standby as the source.
#
# To run a test, the test script (in t/ subdirectory) calls the functions
# in this module. These functions should be called in this sequence:
#
# 1. setup_cluster - creates a PostgreSQL cluster that runs as the master
#
# 2. start_master - starts the master server
#
# 3. create_standby - runs pg_basebackup to initialize a standby server, and
# sets it up to follow the master.
#
# 4. promote_standby - runs "pg_ctl promote" to promote the standby server.
# The old master keeps running.
#
# 5. run_pg_rewind - stops the old master (if it's still running) and runs
# pg_rewind to synchronize it with the now-promoted standby server.
#
# 6. clean_rewind_test - stops both servers used in the test, if they're
# still running.
#
# The test script can use the helper functions master_psql and standby_psql
# to run psql against the master and standby servers, respectively.
use strict;
use warnings;
use Carp;
use Config;
use Exporter 'import';
use File::Copy;
use File::Path qw(rmtree);
use IPC::Run qw(run);
use PostgresNode;
use TestLib;
use Test::More;
our @EXPORT = qw(
$node_master
$node_standby
master_psql
standby_psql
check_query
setup_cluster
start_master
create_standby
promote_standby
run_pg_rewind
clean_rewind_test
);
# Our nodes.
our $node_master;
our $node_standby;
sub master_psql
{
my $cmd = shift;
my $dbname = shift || 'postgres';
system_or_bail 'psql', '-q', '--no-psqlrc', '-d',
$node_master->connstr($dbname), '-c', "$cmd";
return;
}
sub standby_psql
{
my $cmd = shift;
my $dbname = shift || 'postgres';
system_or_bail 'psql', '-q', '--no-psqlrc', '-d',
$node_standby->connstr($dbname), '-c', "$cmd";
return;
}
# Run a query against the master, and check that the output matches what's
# expected
sub check_query
{
local $Test::Builder::Level = $Test::Builder::Level + 1;
my ($query, $expected_stdout, $test_name) = @_;
my ($stdout, $stderr);
# we want just the output, no formatting
my $result = run [
'psql', '-q', '-A', '-t', '--no-psqlrc', '-d',
$node_master->connstr('postgres'),
'-c', $query
],
'>', \$stdout, '2>', \$stderr;
# We don't use ok() for the exit code and stderr, because we want this
# check to be just a single test.
if (!$result)
{
fail("$test_name: psql exit code");
}
elsif ($stderr ne '')
{
diag $stderr;
fail("$test_name: psql no stderr");
}
else
{
$stdout =~ s/\r//g if $Config{osname} eq 'msys';
is($stdout, $expected_stdout, "$test_name: query result matches");
}
return;
}
sub setup_cluster
{
my $extra_name = shift; # Used to differentiate clusters
my $extra = shift; # Extra params for initdb
# Initialize master, data checksums are mandatory
$node_master =
get_new_node('master' . ($extra_name ? "_${extra_name}" : ''));
# Set up pg_hba.conf and pg_ident.conf for the role running
# pg_rewind. This role is used for all the tests, and has
# minimal permissions enough to rewind from an online source.
$node_master->init(
allows_streaming => 1,
extra => $extra,
auth_extra => [ '--create-role', 'rewind_user' ]);
# Set wal_keep_segments to prevent WAL segment recycling after enforced
# checkpoints in the tests.
$node_master->append_conf(
'postgresql.conf', qq(
wal_keep_segments = 20
));
return;
}
sub start_master
{
$node_master->start;
# Create custom role which is used to run pg_rewind, and adjust its
# permissions to the minimum necessary.
$node_master->safe_psql(
'postgres', "
CREATE ROLE rewind_user LOGIN;
GRANT EXECUTE ON function pg_catalog.pg_ls_dir(text, boolean, boolean)
TO rewind_user;
GRANT EXECUTE ON function pg_catalog.pg_stat_file(text, boolean)
TO rewind_user;
GRANT EXECUTE ON function pg_catalog.pg_read_binary_file(text)
TO rewind_user;
GRANT EXECUTE ON function pg_catalog.pg_read_binary_file(text, bigint, bigint, boolean)
TO rewind_user;");
#### Now run the test-specific parts to initialize the master before setting
# up standby
return;
}
sub create_standby
{
my $extra_name = shift;
$node_standby =
get_new_node('standby' . ($extra_name ? "_${extra_name}" : ''));
$node_master->backup('my_backup');
$node_standby->init_from_backup($node_master, 'my_backup');
my $connstr_master = $node_master->connstr();
$node_standby->append_conf(
"postgresql.conf", qq(
primary_conninfo='$connstr_master'
));
$node_standby->set_standby_mode();
# Start standby
$node_standby->start;
# The standby may have WAL to apply before it matches the primary. That
# is fine, because no test examines the standby before promotion.
return;
}
sub promote_standby
{
#### Now run the test-specific parts to run after standby has been started
# up standby
# Wait for the standby to receive and write all WAL.
$node_master->wait_for_catchup($node_standby, 'write');
# Now promote standby and insert some new data on master, this will put
# the master out-of-sync with the standby.
$node_standby->promote;
# Force a checkpoint after the promotion. pg_rewind looks at the control
# file to determine what timeline the server is on, and that isn't updated
# immediately at promotion, but only at the next checkpoint. When running
# pg_rewind in remote mode, it's possible that we complete the test steps
# after promotion so quickly that when pg_rewind runs, the standby has not
# performed a checkpoint after promotion yet.
standby_psql("checkpoint");
return;
}
sub run_pg_rewind
{
my $test_mode = shift;
my $master_pgdata = $node_master->data_dir;
my $standby_pgdata = $node_standby->data_dir;
my $standby_connstr = $node_standby->connstr('postgres');
my $tmp_folder = TestLib::tempdir;
# Append the rewind-specific role to the connection string.
$standby_connstr = "$standby_connstr user=rewind_user";
# Stop the master and be ready to perform the rewind
$node_master->stop;
# At this point, the rewind processing is ready to run.
# We now have a very simple scenario with a few diverged WAL record.
# The real testing begins really now with a bifurcation of the possible
# scenarios that pg_rewind supports.
# Keep a temporary postgresql.conf for master node or it would be
# overwritten during the rewind.
copy(
"$master_pgdata/postgresql.conf",
"$tmp_folder/master-postgresql.conf.tmp");
# Now run pg_rewind
if ($test_mode eq "local")
{
# Do rewind using a local pgdata as source
# Stop the master and be ready to perform the rewind
$node_standby->stop;
command_ok(
[
'pg_rewind',
"--debug",
"--source-pgdata=$standby_pgdata",
"--target-pgdata=$master_pgdata",
"--no-sync"
],
'pg_rewind local');
}
elsif ($test_mode eq "remote")
{
# Do rewind using a remote connection as source
command_ok(
[
'pg_rewind', "--debug",
"--source-server", $standby_connstr,
"--target-pgdata=$master_pgdata", "-R",
"--no-sync"
],
'pg_rewind remote');
# Check that standby.signal has been created.
ok(-e "$master_pgdata/standby.signal");
# Now, when pg_rewind apparently succeeded with minimal permissions,
# add REPLICATION privilege. So we could test that new standby
# is able to connect to the new master with generated config.
$node_standby->safe_psql('postgres',
"ALTER ROLE rewind_user WITH REPLICATION;");
}
else
{
# Cannot come here normally
croak("Incorrect test mode specified");
}
# Now move back postgresql.conf with old settings
move(
"$tmp_folder/master-postgresql.conf.tmp",
"$master_pgdata/postgresql.conf");
chmod(
$node_master->group_access() ? 0640 : 0600,
"$master_pgdata/postgresql.conf")
or BAIL_OUT(
"unable to set permissions for $master_pgdata/postgresql.conf");
# Plug-in rewound node to the now-promoted standby node
if ($test_mode ne "remote")
{
my $port_standby = $node_standby->port;
$node_master->append_conf(
'postgresql.conf', qq(
primary_conninfo='port=$port_standby'));
$node_master->set_standby_mode();
}
# Restart the master to check that rewind went correctly
$node_master->start;
#### Now run the test-specific parts to check the result
return;
}
# Clean up after the test. Stop both servers, if they're still running.
sub clean_rewind_test
{
$node_master->teardown_node if defined $node_master;
$node_standby->teardown_node if defined $node_standby;
return;
}
1;