feat: RED metrics

services/proxy/pkg/command/server.go

@@ -130,7 +130,7 @@ func Server(cfg *config.Config) *cli.Command {
 			}
 
 			{
-				middlewares := loadMiddlewares(ctx, logger, cfg, userInfoCache, traceProvider)
+				middlewares := loadMiddlewares(ctx, logger, cfg, userInfoCache, traceProvider, *m)
 				server, err := proxyHTTP.Server(
 					proxyHTTP.Handler(lh.handler()),
 					proxyHTTP.Logger(logger),
@@ -271,7 +271,7 @@ func (h *StaticRouteHandler) backchannelLogout(w http.ResponseWriter, r *http.Re
 	render.JSON(w, r, nil)
 }
 
-func loadMiddlewares(ctx context.Context, logger log.Logger, cfg *config.Config, userInfoCache microstore.Store, traceProvider trace.TracerProvider) alice.Chain {
+func loadMiddlewares(ctx context.Context, logger log.Logger, cfg *config.Config, userInfoCache microstore.Store, traceProvider trace.TracerProvider, metrics metrics.Metrics) alice.Chain {
 	rolesClient := settingssvc.NewRoleService("com.owncloud.api.settings", cfg.GrpcClient)
 	policiesProviderClient := policiessvc.NewPoliciesProviderService("com.owncloud.api.policies", cfg.GrpcClient)
 	gatewaySelector, err := pool.GatewaySelector(
@@ -386,6 +386,7 @@ func loadMiddlewares(ctx context.Context, logger log.Logger, cfg *config.Config,
 		),
 		middleware.Tracer(traceProvider),
 		pkgmiddleware.TraceContext,
+		middleware.Instrumenter(metrics),
 		chimiddleware.RealIP,
 		chimiddleware.RequestID,
 		middleware.AccessLog(logger),

services/proxy/pkg/metrics/metrics.go

@@ -14,8 +14,8 @@ var (
 
 // Metrics defines the available metrics of this service.
 type Metrics struct {
-	Counter   *prometheus.CounterVec
-	Latency   *prometheus.SummaryVec
+	Requests  *prometheus.CounterVec
+	Errors    *prometheus.CounterVec
 	Duration  *prometheus.HistogramVec
 	BuildInfo *prometheus.GaugeVec
 }
@@ -23,24 +23,24 @@ type Metrics struct {
 // New initializes the available metrics.
 func New() *Metrics {
 	m := &Metrics{
-		Counter: prometheus.NewCounterVec(prometheus.CounterOpts{
+		Requests: prometheus.NewCounterVec(prometheus.CounterOpts{
 			Namespace: Namespace,
 			Subsystem: Subsystem,
-			Name:      "proxy_total",
-			Help:      "How many proxy requests processed",
-		}, []string{}),
-		Latency: prometheus.NewSummaryVec(prometheus.SummaryOpts{
+			Name:      "requests_total",
+			Help:      "How many requests processed in total",
+		}, []string{"method"}),
+		Errors: prometheus.NewCounterVec(prometheus.CounterOpts{
 			Namespace: Namespace,
 			Subsystem: Subsystem,
-			Name:      "proxy_latency_microseconds",
-			Help:      "proxy request latencies in microseconds",
-		}, []string{}),
+			Name:      "errors_total",
+			Help:      "How many requests run into errors",
+		}, []string{"method"}),
 		Duration: prometheus.NewHistogramVec(prometheus.HistogramOpts{
 			Namespace: Namespace,
 			Subsystem: Subsystem,
-			Name:      "proxy_duration_seconds",
-			Help:      "proxy method request time in seconds",
-		}, []string{}),
+			Name:      "duration_seconds",
+			Help:      "request duration in seconds",
+		}, []string{"method"}),
 		BuildInfo: prometheus.NewGaugeVec(prometheus.GaugeOpts{
 			Namespace: Namespace,
 			Subsystem: Subsystem,
@@ -49,8 +49,8 @@ func New() *Metrics {
 		}, []string{"versions"}),
 	}
 
-	_ = prometheus.Register(m.Counter)
-	_ = prometheus.Register(m.Latency)
+	_ = prometheus.Register(m.Requests)
+	_ = prometheus.Register(m.Errors)
 	_ = prometheus.Register(m.Duration)
 	_ = prometheus.Register(m.BuildInfo)
 	return m

services/proxy/pkg/middleware/metrics.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/go-chi/chi/v5/middleware"
+	"github.com/owncloud/ocis/v2/services/proxy/pkg/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Instrumenter provides a middleware to create metrics
+func Instrumenter(m metrics.Metrics) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			start := time.Now()
+			ww := middleware.NewWrapResponseWriter(w, r.ProtoMajor)
+			m.Requests.With(prometheus.Labels{"method": r.Method}).Inc()
+
+			next.ServeHTTP(ww, r)
+
+			m.Duration.With(prometheus.Labels{"method": r.Method}).Observe(float64(time.Since(start).Seconds()))
+			if ww.Status() >= 500 {
+				m.Errors.With(prometheus.Labels{"method": r.Method}).Inc()
+			}
+		})
+	}
+}