Merge pull request #197 from authzed/postgres-prom

fix the postgres prom GC metrics to respect enable prom option

internal/datastore/postgres/options.go

@@ -175,6 +175,8 @@ func GCMaxOperationTime(time time.Duration) Option {
 
 // EnablePrometheusStats enables Prometheus metrics provided by the Postgres
 // clients being used by the datastore.
+//
+// Prometheus metrics are disable by default.
 func EnablePrometheusStats() Option {
 	return func(po *postgresOptions) {
 		po.enablePrometheusStats = true
@@ -183,6 +185,8 @@ func EnablePrometheusStats() Option {
 
 // EnableTracing enables trace-level logging for the Postgres clients being
 // used by the datastore.
+//
+// Tracing is disabled by default.
 func EnableTracing() Option {
 	return func(po *postgresOptions) {
 		po.logger = &tracingLogger{}

internal/datastore/postgres/postgres.go

@@ -59,25 +59,30 @@ const (
 
 var (
 	gcDurationHistogram = prometheus.NewHistogram(prometheus.HistogramOpts{
-		Name:    "postgres_gc_duration",
-		Help:    "postgres garbage collection duration distribution in seconds.",
-		Buckets: []float64{0.01, 0.1, 0.5, 1, 5, 10, 25, 60, 120},
+		Namespace: "spicedb",
+		Subsystem: "datastore",
+		Name:      "postgres_gc_duration",
+		Help:      "postgres garbage collection duration distribution in seconds.",
+		Buckets:   []float64{0.01, 0.1, 0.5, 1, 5, 10, 25, 60, 120},
 	})
 
 	gcRelationshipsClearedGauge = prometheus.NewGauge(prometheus.GaugeOpts{
-		Name: "postgres_relationships_cleared",
-		Help: "number of relationships cleared by postgres garbage collection.",
+		Namespace: "spicedb",
+		Subsystem: "datastore",
+		Name:      "postgres_relationships_cleared",
+		Help:      "number of relationships cleared by postgres garbage collection.",
 	})
 
 	gcTransactionsClearedGauge = prometheus.NewGauge(prometheus.GaugeOpts{
-		Name: "postgres_transactions_cleared",
-		Help: "number of transactions cleared by postgres garbage collection.",
+		Namespace: "spicedb",
+		Subsystem: "datastore",
+		Name:      "postgres_transactions_cleared",
+		Help:      "number of transactions cleared by postgres garbage collection.",
 	})
 )
 
 func init() {
 	dbsql.Register(tracingDriverName, sqlmw.Driver(stdlib.GetDefaultDriver(), new(traceInterceptor)))
-	prometheus.MustRegister(gcDurationHistogram, gcRelationshipsClearedGauge, gcTransactionsClearedGauge)
 }
 
 var (
@@ -144,6 +149,18 @@ func NewPostgresDatastore(
 		if err != nil {
 			return nil, fmt.Errorf(errUnableToInstantiate, err)
 		}
+		err = prometheus.Register(gcDurationHistogram)
+		if err != nil {
+			return nil, fmt.Errorf(errUnableToInstantiate, err)
+		}
+		err = prometheus.Register(gcRelationshipsClearedGauge)
+		if err != nil {
+			return nil, fmt.Errorf(errUnableToInstantiate, err)
+		}
+		err = prometheus.Register(gcTransactionsClearedGauge)
+		if err != nil {
+			return nil, fmt.Errorf(errUnableToInstantiate, err)
+		}
 	}
 
 	gcCtx, cancelGc := context.WithCancel(context.Background())