Consolidate the prometheus Counters into a shared CounterVec and remove

the "code" label from the latencies SummaryVec.

pkg/apiserver/apiserver.go

@@ -23,6 +23,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"path"
+	"strconv"
 	"strings"
 	"time"
 
@@ -42,17 +43,34 @@ import (
 )
 
 var (
-	apiserverLatencies = prometheus.NewSummaryVec(
+	// TODO(a-robinson): Add unit tests for the handling of these metrics once
+	// the upstream library supports it.
+	requestCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "apiserver_request_count",
+			Help: "Counter of apiserver requests broken out for each request handler, verb, API resource, and HTTP response code.",
+		},
+		[]string{"handler", "verb", "resource", "code"},
+	)
+	requestLatencies = prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
 			Name: "apiserver_request_latencies",
-			Help: "Response latency summary in microseconds for each request handler, verb, and HTTP response code.",
+			Help: "Response latency summary in microseconds for each request handler and verb.",
 		},
-		[]string{"handler", "verb", "code"},
+		[]string{"handler", "verb"},
 	)
 )
 
 func init() {
-	prometheus.MustRegister(apiserverLatencies)
+	prometheus.MustRegister(requestCounter)
+	prometheus.MustRegister(requestLatencies)
+}
+
+// monitor is a helper function for each HTTP request handler to use for
+// instrumenting basic request counter and latency metrics.
+func monitor(handler, verb, resource string, httpCode int, reqStart time.Time) {
+	requestCounter.WithLabelValues(handler, verb, resource, strconv.Itoa(httpCode)).Inc()
+	requestLatencies.WithLabelValues(handler, verb).Observe(float64((time.Since(reqStart)) / time.Microsecond))
 }
 
 // mux is an object that can register http handlers.

pkg/apiserver/redirect.go

@@ -18,31 +18,14 @@ package apiserver
 
 import (
 	"net/http"
-	"strconv"
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/httplog"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
-
-	"github.com/prometheus/client_golang/prometheus"
 )
 
-var (
-	redirectCounter = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "apiserver_redirect_count",
-			Help: "Counter of redirect requests broken out by apiserver resource and HTTP response code.",
-		},
-		[]string{"resource", "code"},
-	)
-)
-
-func init() {
-	prometheus.MustRegister(redirectCounter)
-}
-
 type RedirectHandler struct {
 	storage                map[string]RESTStorage
 	codec                  runtime.Codec
@@ -50,13 +33,11 @@ type RedirectHandler struct {
 }
 
 func (r *RedirectHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	apiResource := ""
+	var verb string
+	var apiResource string
 	var httpCode int
 	reqStart := time.Now()
-	defer func() {
-		redirectCounter.WithLabelValues(apiResource, strconv.Itoa(httpCode)).Inc()
-		apiserverLatencies.WithLabelValues("redirect", "get", strconv.Itoa(httpCode)).Observe(float64((time.Since(reqStart)) / time.Microsecond))
-	}()
+	defer func() { monitor("redirect", verb, apiResource, httpCode, reqStart) }()
 
 	requestInfo, err := r.apiRequestInfoResolver.GetAPIRequestInfo(req)
 	if err != nil {
@@ -64,6 +45,7 @@ func (r *RedirectHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		httpCode = http.StatusNotFound
 		return
 	}
+	verb = requestInfo.Verb
 	resource, parts := requestInfo.Resource, requestInfo.Parts
 	ctx := api.WithNamespace(api.NewContext(), requestInfo.Namespace)
 
@@ -78,7 +60,6 @@ func (r *RedirectHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if !ok {
 		httplog.LogOf(req, w).Addf("'%v' has no storage object", resource)
 		notFound(w, req)
-		apiResource = "invalidResource"
 		httpCode = http.StatusNotFound
 		return
 	}

pkg/apiserver/resthandler.go

@@ -19,7 +19,6 @@ package apiserver
 import (
 	"net/http"
 	"path"
-	"strconv"
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/admission"
@@ -29,23 +28,8 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 
 	"github.com/golang/glog"
-	"github.com/prometheus/client_golang/prometheus"
 )
 
-var (
-	restCounter = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "apiserver_rest_count",
-			Help: "Counter of REST requests broken out for each verb, apiserver resource, and HTTP response code.",
-		},
-		[]string{"verb", "resource", "code"},
-	)
-)
-
-func init() {
-	prometheus.MustRegister(restCounter)
-}
-
 // RESTHandler implements HTTP verbs on a set of RESTful resources identified by name.
 type RESTHandler struct {
 	storage                map[string]RESTStorage
@@ -59,14 +43,11 @@ type RESTHandler struct {
 
 // ServeHTTP handles requests to all RESTStorage objects.
 func (h *RESTHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	verb := ""
-	apiResource := ""
+	var verb string
+	var apiResource string
 	var httpCode int
 	reqStart := time.Now()
-	defer func() {
-		restCounter.WithLabelValues(verb, apiResource, strconv.Itoa(httpCode)).Inc()
-		apiserverLatencies.WithLabelValues("rest", verb, strconv.Itoa(httpCode)).Observe(float64((time.Since(reqStart)) / time.Microsecond))
-	}()
+	defer func() { monitor("rest", verb, apiResource, httpCode, reqStart) }()
 
 	requestInfo, err := h.apiRequestInfoResolver.GetAPIRequestInfo(req)
 	if err != nil {