Merge branch 'id-refactor-upstream-metrics' into 'master'

Refactor upstream metrics code

See merge request gitlab-org/gitlab!80958

workhorse/internal/upstream/metrics.go

@@ -6,6 +6,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+
+	"gitlab.com/gitlab-org/labkit/metrics"
 )
 
 const (
@@ -13,95 +15,7 @@ const (
 	httpSubsystem = "http"
 )
 
-func secondsDurationBuckets() []float64 {
-	return []float64{
-		0.005, /* 5ms */
-		0.025, /* 25ms */
-		0.1,   /* 100ms */
-		0.5,   /* 500ms */
-		1.0,   /* 1s */
-		10.0,  /* 10s */
-		30.0,  /* 30s */
-		60.0,  /* 1m */
-		300.0, /* 10m */
-	}
-}
-
-func byteSizeBuckets() []float64 {
-	return []float64{
-		10,
-		64,
-		256,
-		1024,             /* 1kB */
-		64 * 1024,        /* 64kB */
-		256 * 1024,       /* 256kB */
-		1024 * 1024,      /* 1mB */
-		64 * 1024 * 1024, /* 64mB */
-	}
-}
-
 var (
-	httpInFlightRequests = promauto.NewGauge(prometheus.GaugeOpts{
-		Namespace: namespace,
-		Subsystem: httpSubsystem,
-		Name:      "in_flight_requests",
-		Help:      "A gauge of requests currently being served by workhorse.",
-	})
-
-	httpRequestsTotal = promauto.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Subsystem: httpSubsystem,
-			Name:      "requests_total",
-			Help:      "A counter for requests to workhorse.",
-		},
-		[]string{"code", "method", "route"},
-	)
-
-	httpRequestDurationSeconds = promauto.NewHistogramVec(
-		prometheus.HistogramOpts{
-			Namespace: namespace,
-			Subsystem: httpSubsystem,
-			Name:      "request_duration_seconds",
-			Help:      "A histogram of latencies for requests to workhorse.",
-			Buckets:   secondsDurationBuckets(),
-		},
-		[]string{"code", "method", "route"},
-	)
-
-	httpRequestSizeBytes = promauto.NewHistogramVec(
-		prometheus.HistogramOpts{
-			Namespace: namespace,
-			Subsystem: httpSubsystem,
-			Name:      "request_size_bytes",
-			Help:      "A histogram of sizes of requests to workhorse.",
-			Buckets:   byteSizeBuckets(),
-		},
-		[]string{"code", "method", "route"},
-	)
-
-	httpResponseSizeBytes = promauto.NewHistogramVec(
-		prometheus.HistogramOpts{
-			Namespace: namespace,
-			Subsystem: httpSubsystem,
-			Name:      "response_size_bytes",
-			Help:      "A histogram of response sizes for requests to workhorse.",
-			Buckets:   byteSizeBuckets(),
-		},
-		[]string{"code", "method", "route"},
-	)
-
-	httpTimeToWriteHeaderSeconds = promauto.NewHistogramVec(
-		prometheus.HistogramOpts{
-			Namespace: namespace,
-			Subsystem: httpSubsystem,
-			Name:      "time_to_write_header_seconds",
-			Help:      "A histogram of request durations until the response headers are written.",
-			Buckets:   secondsDurationBuckets(),
-		},
-		[]string{"code", "method", "route"},
-	)
-
 	httpGeoProxiedRequestsTotal = promauto.NewCounterVec(
 		prometheus.CounterOpts{
 			Namespace: namespace,
@@ -111,19 +25,12 @@ var (
 		},
 		[]string{"code", "method", "route"},
 	)
+
+	buildHandler = metrics.NewHandlerFactory(metrics.WithNamespace(namespace), metrics.WithLabels("route"))
 )
 
 func instrumentRoute(next http.Handler, method string, regexpStr string) http.Handler {
-	handler := next
-
-	handler = promhttp.InstrumentHandlerCounter(httpRequestsTotal.MustCurryWith(map[string]string{"route": regexpStr}), handler)
-	handler = promhttp.InstrumentHandlerDuration(httpRequestDurationSeconds.MustCurryWith(map[string]string{"route": regexpStr}), handler)
-	handler = promhttp.InstrumentHandlerInFlight(httpInFlightRequests, handler)
-	handler = promhttp.InstrumentHandlerRequestSize(httpRequestSizeBytes.MustCurryWith(map[string]string{"route": regexpStr}), handler)
-	handler = promhttp.InstrumentHandlerResponseSize(httpResponseSizeBytes.MustCurryWith(map[string]string{"route": regexpStr}), handler)
-	handler = promhttp.InstrumentHandlerTimeToWriteHeader(httpTimeToWriteHeaderSeconds.MustCurryWith(map[string]string{"route": regexpStr}), handler)
-
-	return handler
+	return buildHandler(next, metrics.WithLabelValues(map[string]string{"route": regexpStr}))
 }
 
 func instrumentGeoProxyRoute(next http.Handler, method string, regexpStr string) http.Handler {