update debugserver http handler and gorouter SetMinLevel

Author: navinms711

src/code.cloudfoundry.org/gorouter/cmd/gorouter/main.go

@@ -56,14 +56,14 @@ var (
 // It implements the lager.Sink interface, allowing it to be used with
 // lager's logging system. The Log method logs the message and source
 // using the slog.Logger, and the LogLevel method returns the current
-// logging level. 
+// logging level.
 
 type zapLevelSink struct {
 	logger *slog.Logger
 }
 
-func (s *zapLevelSink) Log(lf lager.LogFormat) {
-	s.logger.Info("zapLevelSink Log()", slog.String("Zap Level Sink log invoked", lf.Message),
+func (z *zapLevelSink) Log(lf lager.LogFormat) {
+	z.logger.Info("zapLevelSink Log()", slog.String("Zap Level Sink log invoked", lf.Message),
 		slog.String("source", lf.Source))
 }
 
@@ -88,23 +88,34 @@ func (z *zapLevelSink) LogLevel() lager.LogLevel {
 // before using this sink, and it will log an info message when the
 // logging level is updated.
 
-func (s *zapLevelSink) SetMinLevel(level lager.LogLevel) {
+func (z *zapLevelSink) SetMinLevel(level lager.LogLevel) {
 	var zapLevel zapcore.Level
 	switch level {
 	case lager.DEBUG:
 		zapLevel = zapcore.DebugLevel
 	case lager.INFO:
 		zapLevel = zapcore.InfoLevel
 	case lager.ERROR, lager.FATAL:
+		// For lager.ERROR and lager.FATAL, we use zapcore.ErrorLevel.
+		// This is because zapcore.ErrorLevel captures both error and fatal logs.
+		// Using zapcore.FatalLevel would cause the application to exit immediately.
+		// Because zapcore.FatalLevel calls os.Exit(1) after logging the message.
 		zapLevel = zapcore.ErrorLevel
 	default:
 		zapLevel = zapcore.InfoLevel
 	}
 
 	grlog.SetLoggingLevel(zapLevel.String())
 
-	if s.logger != nil {
-		s.logger.Info("zapcore log level updated", slog.String("new-level", zapLevel.String()))
+	// Print the new log level to the logger to confirm the change.
+	// This is useful for debugging and confirming that the log level has been updated.
+	if z.logger != nil {
+		// We cannot use z.logger.Info() directly here because it won't print the
+		// log level when it is set to zapcore.ErrorLevel or zapcore.FatalLevel.
+		// Instead, we use slog.New() to log the message. This ensures that the
+		// log level change is always logged, regardless of the current log level.
+		tmpLogger := slog.New(slog.NewTextHandler(os.Stdout, nil))
+		tmpLogger.Info("Gorouter logger -> zapcore log level updated.", slog.String("new-level", z.LogLevel().String()))
 	}
 }
 

src/code.cloudfoundry.org/gorouter/integration/main_test.go

@@ -2,6 +2,7 @@ package integration
 
 import (
 	"bufio"
+	"bytes"
 	"crypto/tls"
 	"encoding/json"
 	"errors"
@@ -618,6 +619,78 @@ var _ = Describe("Router Integration", func() {
 		Consistently(contentsFunc).ShouldNot(ContainSubstring("Component Router registered successfully"))
 	})
 
+	Context("It starts up a debugserver", func() {
+		var (
+			testState    *testState
+			contentsFunc func() string = func() string {
+				return string(gorouterSession.Out.Contents())
+			}
+		)
+
+		BeforeEach(func() {
+
+			testState = NewTestState()
+			testState.cfg.DebugAddr = "127.0.0.1:17017"
+			gorouterSession = testState.StartGorouter()
+		})
+
+		It("can change the debugserver's logging level", func() {
+
+			Consistently(contentsFunc).ShouldNot(ContainSubstring(`{log_level":0,"timestamp"`))
+
+			request, err := http.NewRequest("POST", fmt.Sprintf("http://%s/log-level", testState.cfg.DebugAddr), bytes.NewBufferString("debug"))
+			Expect(err).NotTo(HaveOccurred())
+
+			response, err := http.DefaultClient.Do(request)
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(response.StatusCode).To(Equal(http.StatusOK))
+			response.Body.Close()
+
+			Consistently(contentsFunc).Should(ContainSubstring(`{"log_level":0,"timestamp"`))
+
+			// And back to info level
+			gorouterSession.Out.Clear()
+			request, err = http.NewRequest("POST", fmt.Sprintf("http://%s/log-level", testState.cfg.DebugAddr), bytes.NewBufferString("info"))
+			Expect(err).NotTo(HaveOccurred())
+
+			response, err = http.DefaultClient.Do(request)
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(response.StatusCode).To(Equal(http.StatusOK))
+			response.Body.Close()
+
+			//Terminate everything just to generate some info logs
+			testState.StopAndCleanup()
+
+			Consistently(contentsFunc).ShouldNot(ContainSubstring(`{"log_level":0,"timestamp"`))
+			Eventually(contentsFunc).Should(ContainSubstring(`{"log_level":1,"timestamp"`))
+
+		})
+
+		It("Does not accept invalid debug levels", func() {
+
+			Consistently(contentsFunc).ShouldNot(ContainSubstring(`{log_level":0,"timestamp"`))
+
+			gorouterSession.Out.Clear()
+
+			request, err := http.NewRequest("POST", fmt.Sprintf("http://%s/log-level", testState.cfg.DebugAddr), bytes.NewBufferString("meow"))
+			Expect(err).NotTo(HaveOccurred())
+
+			response, err := http.DefaultClient.Do(request)
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(response.StatusCode).ToNot(Equal(http.StatusOK))
+			response.Body.Close()
+
+			Expect(gorouterSession.ExitCode()).To(Equal(-1))
+
+			Consistently(contentsFunc).ShouldNot(ContainSubstring(`{"log_level":0,"timestamp"`))
+			Eventually(contentsFunc).Should(ContainSubstring(`{"log_level":1,"timestamp"`))
+		})
+
+	})
+
 	Describe("loggregator metrics emitted", func() {
 		var (
 			fakeMetron test_util.FakeMetron