1 files changed, 117 insertions, 0 deletions
diff --git a/workhorse/internal/upstream/metrics.go b/workhorse/internal/upstream/metrics.go
new file mode 100644
index 00000000000..38528056d43
--- /dev/null
+++ b/workhorse/internal/upstream/metrics.go
@@ -0,0 +1,117 @@
+package upstream
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+const (
+	namespace     = "gitlab_workhorse"
+	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"},
+	)
+)
+
+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
+}