X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/d27d94532c173335cae9dddc30f1cc9a2e372bd7..09963d2b633769549eea8739be3b541835839462:/sdk/go/httpserver/metrics.go

diff --git a/sdk/go/httpserver/metrics.go b/sdk/go/httpserver/metrics.go
index 1f7d44752b..f3291f6c5e 100644
--- a/sdk/go/httpserver/metrics.go
+++ b/sdk/go/httpserver/metrics.go
@@ -10,15 +10,21 @@ import (
 	"strings"
 	"time"
 
-	"git.curoverse.com/arvados.git/sdk/go/stats"
-	"github.com/Sirupsen/logrus"
+	"git.arvados.org/arvados.git/sdk/go/auth"
+	"git.arvados.org/arvados.git/sdk/go/stats"
 	"github.com/gogo/protobuf/jsonpb"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/sirupsen/logrus"
 )
 
 type Handler interface {
 	http.Handler
+
+	// Returns an http.Handler that serves the Handler's metrics
+	// data at /metrics and /metrics.json, and passes other
+	// requests through to next.
+	ServeAPI(token string, next http.Handler) http.Handler
 }
 
 type metrics struct {
@@ -34,6 +40,8 @@ func (*metrics) Levels() []logrus.Level {
 	return logrus.AllLevels
 }
 
+// Fire implements logrus.Hook in order to collect data points from
+// request logs.
 func (m *metrics) Fire(ent *logrus.Entry) error {
 	if tts, ok := ent.Data["timeToStatus"].(stats.Duration); !ok {
 	} else if method, ok := ent.Data["reqMethod"].(string); !ok {
@@ -57,23 +65,57 @@ func (m *metrics) exportJSON(w http.ResponseWriter, req *http.Request) {
 	w.Write([]byte{']'})
 }
 
+// ServeHTTP implements http.Handler.
 func (m *metrics) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	switch {
-	case req.Method != "GET" && req.Method != "HEAD":
-		m.next.ServeHTTP(w, req)
-	case req.URL.Path == "/metrics.json":
-		m.exportJSON(w, req)
-	case req.URL.Path == "/metrics":
-		m.exportProm.ServeHTTP(w, req)
-	default:
-		m.next.ServeHTTP(w, req)
-	}
+	m.next.ServeHTTP(w, req)
+}
+
+// ServeAPI returns a new http.Handler that serves current data at
+// metrics API endpoints (currently "GET /metrics(.json)?") and passes
+// other requests through to next.
+//
+// If the given token is not empty, that token must be supplied by a
+// client in order to access the metrics endpoints.
+//
+// Typical example:
+//
+//	m := Instrument(...)
+//	srv := http.Server{Handler: m.ServeAPI("secrettoken", m)}
+func (m *metrics) ServeAPI(token string, next http.Handler) http.Handler {
+	jsonMetrics := auth.RequireLiteralToken(token, http.HandlerFunc(m.exportJSON))
+	plainMetrics := auth.RequireLiteralToken(token, m.exportProm)
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		switch {
+		case req.Method != "GET" && req.Method != "HEAD":
+			next.ServeHTTP(w, req)
+		case req.URL.Path == "/metrics.json":
+			jsonMetrics.ServeHTTP(w, req)
+		case req.URL.Path == "/metrics":
+			plainMetrics.ServeHTTP(w, req)
+		default:
+			next.ServeHTTP(w, req)
+		}
+	})
 }
 
-func Instrument(logger *logrus.Logger, next http.Handler) Handler {
+// Instrument returns a new Handler that passes requests through to
+// the next handler in the stack, and tracks metrics of those
+// requests.
+//
+// For the metrics to be accurate, the caller must ensure every
+// request passed to the Handler also passes through
+// LogRequests(...), and vice versa.
+//
+// If registry is nil, a new registry is created.
+//
+// If logger is nil, logrus.StandardLogger() is used.
+func Instrument(registry *prometheus.Registry, logger *logrus.Logger, next http.Handler) Handler {
 	if logger == nil {
 		logger = logrus.StandardLogger()
 	}
+	if registry == nil {
+		registry = prometheus.NewRegistry()
+	}
 	reqDuration := prometheus.NewSummaryVec(prometheus.SummaryOpts{
 		Name: "request_duration_seconds",
 		Help: "Summary of request duration.",
@@ -82,7 +124,6 @@ func Instrument(logger *logrus.Logger, next http.Handler) Handler {
 		Name: "time_to_status_seconds",
 		Help: "Summary of request TTFB.",
 	}, []string{"code", "method"})
-	registry := prometheus.NewRegistry()
 	registry.MustRegister(timeToStatus)
 	registry.MustRegister(reqDuration)
 	m := &metrics{