Added command-line flag to disable the default metrics

.gitignore

@@ -5,6 +5,7 @@
 *.test
 *-stamp
 /.idea
+/.vscode
 *.iml
 /cover.out
 /cover.*.out

README.md

@@ -102,6 +102,12 @@ rich self-documenting metrics for the exporter.
 The -extend.query-path command-line argument specifies a YAML file containing additional queries to run.
 Some examples are provided in [queries.yaml](queries.yaml).
 
+### Working with non-officially-supported postgres versions
+
+If you want to use this exporter to monitor a postgres installation that is not officially supported (e.g. 8.2.15) or a variant of postgres (e.g. Greenplum). 
+You may try to disable all internal metrics using the  -disable-default-metrics command-line argument, then supply your own set of metrics definitions in 
+an external config file.
+
 ### Running as non-superuser
 
 To be able to collect metrics from pg_stat_activity and pg_stat_replication as non-superuser you have to create views as a superuser, and assign permissions separately to those.  In PostgreSQL, views run with the permissions of the user that created them so they can act as security barriers.

cmd/postgres_exporter/postgres_exporter.go

@@ -35,6 +35,7 @@ var Version = "0.0.1"
 var (
 	listenAddress         = kingpin.Flag("web.listen-address", "Address to listen on for web interface and telemetry.").Default(":9187").OverrideDefaultFromEnvar("PG_EXPORTER_WEB_LISTEN_ADDRESS").String()
 	metricPath            = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").OverrideDefaultFromEnvar("PG_EXPORTER_WEB_TELEMETRY_PATH").String()
+	disableDefaultMetrics = kingpin.Flag("disable-default-metrics", "Do not include default metrics.").Default("false").OverrideDefaultFromEnvar("PG_EXPORTER_DISABLE_DEFAULT_METRICS").Bool()
 	queriesPath           = kingpin.Flag("extend.query-path", "Path to custom queries to run.").Default("").OverrideDefaultFromEnvar("PG_EXPORTER_EXTEND_QUERY_PATH").String()
 	onlyDumpMaps          = kingpin.Flag("dumpmaps", "Do not run, simply dump the maps.").Bool()
 )
@@ -669,6 +670,7 @@ type Exporter struct {
 	builtinMetricMaps map[string]map[string]ColumnMapping
 
 	dsn                   string
+	disableDefaultMetrics bool
 	userQueriesPath       string
 	duration              prometheus.Gauge
 	error                 prometheus.Gauge
@@ -692,10 +694,11 @@ type Exporter struct {
 }
 
 // NewExporter returns a new PostgreSQL exporter for the provided DSN.
-func NewExporter(dsn string, userQueriesPath string) *Exporter {
+func NewExporter(dsn string, disableDefaultMetrics bool, userQueriesPath string) *Exporter {
 	return &Exporter{
 		builtinMetricMaps: builtinMetricMaps,
 		dsn:               dsn,
+		disableDefaultMetrics: disableDefaultMetrics,
 		userQueriesPath:       userQueriesPath,
 		duration: prometheus.NewGauge(prometheus.GaugeOpts{
 			Namespace: namespace,
@@ -913,7 +916,7 @@ func (e *Exporter) checkMapVersions(ch chan<- prometheus.Metric, db *sql.DB) err
 	if err != nil {
 		return fmt.Errorf("Error parsing version string: %v", err)
 	}
-	if semanticVersion.LT(lowestSupportedVersion) {
+	if !e.disableDefaultMetrics && semanticVersion.LT(lowestSupportedVersion) {
 		log.Warnln("PostgreSQL version is lower then our lowest supported version! Got", semanticVersion.String(), "minimum supported is", lowestSupportedVersion.String())
 	}
 
@@ -922,8 +925,18 @@ func (e *Exporter) checkMapVersions(ch chan<- prometheus.Metric, db *sql.DB) err
 		log.Infoln("Semantic Version Changed:", e.lastMapVersion.String(), "->", semanticVersion.String())
 		e.mappingMtx.Lock()
 
+		if e.disableDefaultMetrics {
+			e.metricMap = make(map[string]MetricMapNamespace)
+		} else {
 			e.metricMap = makeDescMap(semanticVersion, e.builtinMetricMaps)
+		}
+
+		if e.disableDefaultMetrics {
+			e.queryOverrides = make(map[string]string)
+		} else {
 			e.queryOverrides = makeQueryOverrideMap(semanticVersion, queryOverrides)
+		}
+
 		e.lastMapVersion = semanticVersion
 
 		if e.userQueriesPath != "" {
@@ -1106,7 +1119,7 @@ func main() {
 		log.Fatal("couldn't find environment variables describing the datasource to use")
 	}
 
-	exporter := NewExporter(dsn, *queriesPath)
+	exporter := NewExporter(dsn, *disableDefaultMetrics, *queriesPath)
 	defer func() {
 		if exporter.dbConnection != nil {
 			exporter.dbConnection.Close() // nolint: errcheck

cmd/postgres_exporter/postgres_exporter_integration_test.go

@@ -31,7 +31,7 @@ func (s *IntegrationSuite) SetUpSuite(c *C) {
 	dsn := os.Getenv("DATA_SOURCE_NAME")
 	c.Assert(dsn, Not(Equals), "")
 
-	exporter := NewExporter(dsn, "")
+	exporter := NewExporter(dsn, false, "")
 	c.Assert(exporter, NotNil)
 	// Assign the exporter to the suite
 	s.e = exporter
@@ -86,12 +86,12 @@ func (s *IntegrationSuite) TestInvalidDsnDoesntCrash(c *C) {
 	}()
 
 	// Send a bad DSN
-	exporter := NewExporter("invalid dsn", *queriesPath)
+	exporter := NewExporter("invalid dsn", false, *queriesPath)
 	c.Assert(exporter, NotNil)
 	exporter.scrape(ch)
 
 	// Send a DSN to a non-listening port.
-	exporter = NewExporter("postgresql://nothing:nothing@127.0.0.1:1/nothing", *queriesPath)
+	exporter = NewExporter("postgresql://nothing:nothing@127.0.0.1:1/nothing", false, *queriesPath)
 	c.Assert(exporter, NotNil)
 	exporter.scrape(ch)
 }
@@ -109,7 +109,7 @@ func (s *IntegrationSuite) TestUnknownMetricParsingDoesntCrash(c *C) {
 	dsn := os.Getenv("DATA_SOURCE_NAME")
 	c.Assert(dsn, Not(Equals), "")
 
-	exporter := NewExporter(dsn, "")
+	exporter := NewExporter(dsn, false, "")
 	c.Assert(exporter, NotNil)
 
 	// Convert the default maps into a list of empty maps.