prometheus/postgres_exporter
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Localize the shared database connection to the Exporter object.

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This allows the integration tests to properly exercise configuration parameters.
This commit is contained in:
Will Rouesnel
2017-08-03 23:12:10 +10:00
parent 41cb2e7a68
commit c692b4e76a
1 changed files with 21 additions and 7 deletions
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28
postgres_exporter.go
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@@ -28,8 +28,6 @@ import (
// (semantic version)-(commitish) form. // (semantic version)-(commitish) form.
var Version = "0.0.1" var Version = "0.0.1"
var sharedDBConn *sql.DB
var ( var (
listenAddress = flag.String( listenAddress = flag.String(
"web.listen-address", ":9187", "web.listen-address", ":9187",
@@ -673,6 +671,11 @@ type Exporter struct {
duration, error prometheus.Gauge duration, error prometheus.Gauge
totalScrapes prometheus.Counter totalScrapes prometheus.Counter
// dbDsn is the connection string used to establish the dbConnection
dbDsn string
// dbConnection is used to allow re-using the DB connection between scrapes
dbConnection *sql.DB
// Last version used to calculate metric map. If mismatch on scrape, // Last version used to calculate metric map. If mismatch on scrape,
// then maps are recalculated. // then maps are recalculated.
lastMapVersion semver.Version lastMapVersion semver.Version
@@ -923,8 +926,16 @@ func (e *Exporter) checkMapVersions(ch chan<- prometheus.Metric, db *sql.DB) err
return nil return nil
} }
func getDB(conn string) (*sql.DB, error) { func (e *Exporter) getDB(conn string) (*sql.DB, error) {
if sharedDBConn == nil { // Has dsn changed?
if (e.dbConnection != nil) && (e.dsn != e.dbDsn) {
err := e.dbConnection.Close()
log.Warnln("Error while closing obsolete DB connection:", err)
e.dbConnection = nil
e.dbDsn = ""
}
if e.dbConnection == nil {
d, err := sql.Open("postgres", conn) d, err := sql.Open("postgres", conn)
if err != nil { if err != nil {
return nil, err return nil, err
@@ -935,10 +946,12 @@ func getDB(conn string) (*sql.DB, error) {
} }
d.SetMaxOpenConns(1) d.SetMaxOpenConns(1)
d.SetMaxIdleConns(1) d.SetMaxIdleConns(1)
sharedDBConn = d e.dbConnection = d
e.dbDsn = e.dsn
log.Infoln("Established new database connection.")
} }
return sharedDBConn, nil return e.dbConnection, nil
} }
func (e *Exporter) scrape(ch chan<- prometheus.Metric) { func (e *Exporter) scrape(ch chan<- prometheus.Metric) {
@@ -949,10 +962,11 @@ func (e *Exporter) scrape(ch chan<- prometheus.Metric) {
e.error.Set(0) e.error.Set(0)
e.totalScrapes.Inc() e.totalScrapes.Inc()
db, err := getDB(e.dsn) db, err := e.getDB(e.dsn)
if err != nil { if err != nil {
loggableDsn := "could not parse DATA_SOURCE_NAME" loggableDsn := "could not parse DATA_SOURCE_NAME"
if pDsn, pErr := url.Parse(e.dsn); pErr != nil { if pDsn, pErr := url.Parse(e.dsn); pErr != nil {
log.Debugln("Blanking password for loggable DSN:", e.dsn)
pDsn.User = url.UserPassword(pDsn.User.Username(), "xxx") pDsn.User = url.UserPassword(pDsn.User.Username(), "xxx")
loggableDsn = pDsn.String() loggableDsn = pDsn.String()
} }