UPSTREAM: <carry>: add http logging for kubelet metrics endpoint

Author: tkashem

pkg/kubelet/server/server.go

@@ -474,15 +474,17 @@ func (s *Server) InstallAuthNotRequiredHandlers() {
 		r.RawMustRegister(metrics.NewPrometheusCollector(prometheusHostAdapter{s.host}, containerPrometheusLabelsFunc(s.host), includedMetrics, clock.RealClock{}, cadvisorOpts))
 	}
 	s.restfulCont.Handle(cadvisorMetricsPath,
-		compbasemetrics.HandlerFor(r, compbasemetrics.HandlerOpts{ErrorHandling: compbasemetrics.ContinueOnError}),
-	)
+		WithHTTPLogging(
+			compbasemetrics.HandlerFor(r, compbasemetrics.HandlerOpts{ErrorHandling: compbasemetrics.ContinueOnError}),
+		))
 
 	s.addMetricsBucketMatcher("metrics/resource")
 	resourceRegistry := compbasemetrics.NewKubeRegistry()
 	resourceRegistry.CustomMustRegister(collectors.NewResourceMetricsCollector(s.resourceAnalyzer))
 	s.restfulCont.Handle(resourceMetricsPath,
-		compbasemetrics.HandlerFor(resourceRegistry, compbasemetrics.HandlerOpts{ErrorHandling: compbasemetrics.ContinueOnError}),
-	)
+		WithHTTPLogging(
+			compbasemetrics.HandlerFor(resourceRegistry, compbasemetrics.HandlerOpts{ErrorHandling: compbasemetrics.ContinueOnError}),
+		))
 
 	// prober metrics are exposed under a different endpoint
 

pkg/kubelet/server/server_patch.go

@@ -0,0 +1,119 @@
+package server
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"k8s.io/apiserver/pkg/audit"
+	"k8s.io/apiserver/pkg/endpoints/responsewriter"
+	"k8s.io/klog/v2"
+
+	"github.com/google/uuid"
+)
+
+func WithHTTPLogging(handler http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		logger := newHTTPLogger(w, req)
+		defer logger.log()
+
+		w = responsewriter.WrapForHTTP1Or2(logger)
+		handler.ServeHTTP(w, req)
+	})
+}
+
+func newHTTPLogger(w http.ResponseWriter, req *http.Request) *httpLogger {
+	auditID := audit.GetAuditIDTruncated(req.Context())
+	if len(auditID) == 0 {
+		auditID = uuid.New().String()
+	}
+	return &httpLogger{
+		w:          w,
+		startedAt:  time.Now(),
+		method:     req.Method,
+		requestURI: req.RequestURI,
+		auditID:    auditID,
+		userAgent:  req.UserAgent(),
+		srcIP:      req.RemoteAddr,
+	}
+}
+
+type httpLogger struct {
+	w http.ResponseWriter
+
+	method     string
+	requestURI string
+	auditID    string
+	userAgent  string
+	srcIP      string
+
+	startedAt      time.Time
+	writeLatency   time.Duration
+	flushLatency   time.Duration
+	writeBytes     int
+	statusRecorded bool
+	statusCode     int
+}
+
+var _ http.ResponseWriter = &httpLogger{}
+var _ responsewriter.UserProvidedDecorator = &httpLogger{}
+
+func (l *httpLogger) Unwrap() http.ResponseWriter {
+	return l.w
+}
+
+// Header implements http.ResponseWriter.
+func (l *httpLogger) Header() http.Header {
+	return l.w.Header()
+}
+
+// Write implements http.ResponseWriter.
+func (l *httpLogger) Write(b []byte) (int, error) {
+	if !l.statusRecorded {
+		l.record(http.StatusOK) // Default if WriteHeader hasn't been called
+	}
+	now := time.Now()
+	var written int
+	defer func() {
+		l.writeLatency += time.Since(now)
+		l.writeBytes += written
+	}()
+	written, err := l.w.Write(b)
+	return written, err
+}
+
+func (l *httpLogger) Flush() {
+	now := time.Now()
+	defer func() {
+		l.flushLatency += time.Since(now)
+	}()
+	l.w.(http.Flusher).Flush()
+}
+
+// WriteHeader implements http.ResponseWriter.
+func (l *httpLogger) WriteHeader(status int) {
+	l.record(status)
+	l.w.WriteHeader(status)
+}
+
+func (l *httpLogger) record(status int) {
+	l.statusCode = status
+	l.statusRecorded = true
+}
+
+func (l *httpLogger) log() {
+	latency := time.Since(l.startedAt)
+	kvs := []interface{}{
+		"method", l.method,
+		"URI", l.requestURI,
+		"latency", latency,
+		"userAgent", l.userAgent,
+		"audit-ID", l.auditID,
+		"srcIP", l.srcIP,
+		"status", l.statusCode,
+		"writeLatency", l.writeLatency,
+		"writtenBytes", fmt.Sprintf("%dK", l.writeBytes/1024),
+		"flushLatency", l.flushLatency,
+	}
+	klog.V(1).InfoSDepth(1, "HTTP", kvs...)
+}