remove client label from apiserver request count metric since it is unbounded

Change-Id: I3a9eacebc9d9dc9ed6347260d9378cdcb5743431

Author: Han Kang

staging/src/k8s.io/apiserver/pkg/endpoints/metrics/BUILD

@@ -3,13 +3,6 @@ package(default_visibility = ["//visibility:public"])
 load(
     "@io_bazel_rules_go//go:def.bzl",
     "go_library",
-    "go_test",
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["metrics_test.go"],
-    embed = [":go_default_library"],
 )
 
 go_library(
@@ -20,7 +13,6 @@ go_library(
     deps = [
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/validation:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
-        "//staging/src/k8s.io/apimachinery/pkg/util/net:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/endpoints/request:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/features:go_default_library",

staging/src/k8s.io/apiserver/pkg/endpoints/metrics/metrics.go

@@ -31,7 +31,6 @@ import (
 
 	"k8s.io/apimachinery/pkg/apis/meta/v1/validation"
 	"k8s.io/apimachinery/pkg/types"
-	utilnet "k8s.io/apimachinery/pkg/util/net"
 	utilsets "k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apiserver/pkg/endpoints/request"
 	"k8s.io/apiserver/pkg/features"
@@ -65,14 +64,14 @@ var (
 	requestCounter = compbasemetrics.NewCounterVec(
 		&compbasemetrics.CounterOpts{
 			Name:           "apiserver_request_total",
-			Help:           "Counter of apiserver requests broken out for each verb, dry run value, group, version, resource, scope, component, client, and HTTP response contentType and code.",
+			Help:           "Counter of apiserver requests broken out for each verb, dry run value, group, version, resource, scope, component, and HTTP response contentType and code.",
 			StabilityLevel: compbasemetrics.ALPHA,
 		},
 		// The label_name contentType doesn't follow the label_name convention defined here:
 		// https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/instrumentation.md
 		// But changing it would break backwards compatibility. Future label_names
 		// should be all lowercase and separated by underscores.
-		[]string{"verb", "dry_run", "group", "version", "resource", "subresource", "scope", "component", "client", "contentType", "code"},
+		[]string{"verb", "dry_run", "group", "version", "resource", "subresource", "scope", "component", "contentType", "code"},
 	)
 	longRunningRequestGauge = compbasemetrics.NewGaugeVec(
 		&compbasemetrics.GaugeOpts{
@@ -256,9 +255,8 @@ func RecordLongRunning(req *http.Request, requestInfo *request.RequestInfo, comp
 func MonitorRequest(req *http.Request, verb, group, version, resource, subresource, scope, component, contentType string, httpCode, respSize int, elapsed time.Duration) {
 	reportedVerb := cleanVerb(verb, req)
 	dryRun := cleanDryRun(req.URL)
-	client := cleanUserAgent(utilnet.GetHTTPClient(req))
 	elapsedSeconds := elapsed.Seconds()
-	requestCounter.WithLabelValues(reportedVerb, dryRun, group, version, resource, subresource, scope, component, client, contentType, codeToString(httpCode)).Inc()
+	requestCounter.WithLabelValues(reportedVerb, dryRun, group, version, resource, subresource, scope, component, contentType, codeToString(httpCode)).Inc()
 	requestLatencies.WithLabelValues(reportedVerb, dryRun, group, version, resource, subresource, scope, component).Observe(elapsedSeconds)
 	// We are only interested in response sizes of read requests.
 	if verb == "GET" || verb == "LIST" {
@@ -376,19 +374,6 @@ func cleanDryRun(u *url.URL) string {
 	return strings.Join(utilsets.NewString(dryRun...).List(), ",")
 }
 
-func cleanUserAgent(ua string) string {
-	// We collapse all "web browser"-type user agents into one "browser" to reduce metric cardinality.
-	if strings.HasPrefix(ua, "Mozilla/") {
-		return "Browser"
-	}
-	// If an old "kubectl.exe" has passed us its full path, we discard the path portion.
-	if kubectlExeRegexp.MatchString(ua) {
-		// avoid an allocation
-		ua = kubectlExeRegexp.ReplaceAllString(ua, "$1")
-	}
-	return ua
-}
-
 // ResponseWriterDelegator interface wraps http.ResponseWriter to additionally record content-length, status-code, etc.
 type ResponseWriterDelegator struct {
 	http.ResponseWriter