Respect log format flag/config for stdout logs

internal/logger/logger.go

@@ -33,6 +33,9 @@ import (
 // gcsfuse.log in case of GCSFuse.
 const ProgrammeName string = "gcsfuse"
 const GCSFuseInBackgroundMode string = "GCSFUSE_IN_BACKGROUND_MODE"
+const jsonFormat string = "json"
+const textFormat string = "text"
+const defaultFormat string = jsonFormat
 
 var (
 	defaultLoggerFactory *loggerFactory
@@ -98,12 +101,22 @@ func InitLogFile(logConfig config.LogConfig) error {
 func init() {
 	defaultLoggerFactory = &loggerFactory{
 		file:            nil,
+		format:          defaultFormat,
 		level:           config.INFO, // setting log level to INFO by default
 		logRotateConfig: config.DefaultLogRotateConfig(),
 	}
 	defaultLogger = defaultLoggerFactory.newLogger(config.INFO)
 }
 
+// SetLogFormat updates the log format of default logger.
+func SetLogFormat(format string) {
+	if format == defaultLoggerFactory.format {
+		return
+	}
+	defaultLoggerFactory.format = format
+	defaultLogger = defaultLoggerFactory.newLogger(defaultLoggerFactory.level)
+}
+
 // Close closes the log file when necessary.
 func Close() {
 	if f := defaultLoggerFactory.file; f != nil {
@@ -169,7 +182,7 @@ func (f *loggerFactory) newLogger(level config.LogSeverity) *slog.Logger {
 }
 
 func (f *loggerFactory) createJsonOrTextHandler(writer io.Writer, levelVar *slog.LevelVar, prefix string) slog.Handler {
-	if f.format == "text" {
+	if f.format == textFormat {
 		return slog.NewTextHandler(writer, getHandlerOptions(levelVar, prefix, f.format))
 	}
 	return slog.NewJSONHandler(writer, getHandlerOptions(levelVar, prefix, f.format))

internal/logger/logger_test.go

@@ -50,20 +50,21 @@ func init() { RegisterTestSuite(&LoggerTest{}) }
 // Boilerplate
 // //////////////////////////////////////////////////////////////////////
 
+func redirectLogsToGivenBuffer(buf *bytes.Buffer, level config.LogSeverity) {
+	var programLevel = new(slog.LevelVar)
+	defaultLogger = slog.New(
+		defaultLoggerFactory.createJsonOrTextHandler(buf, programLevel, "TestLogs: "),
+	)
+	setLoggingLevel(level, programLevel)
+}
+
 // fetchLogOutputForSpecifiedSeverityLevel takes configured severity and
 // functions that write logs as parameter and returns string array containing
 // output from each function call.
 func fetchLogOutputForSpecifiedSeverityLevel(level config.LogSeverity, functions []func()) []string {
 	// create a logger that writes to buffer at configured level.
 	var buf bytes.Buffer
-	var programLevel = new(slog.LevelVar)
-	logger := slog.New(
-		defaultLoggerFactory.createJsonOrTextHandler(&buf, programLevel, "TestLogs: "),
-	)
-	setLoggingLevel(level, programLevel)
-
-	// make the created logger default.
-	defaultLogger = logger
+	redirectLogsToGivenBuffer(&buf, level)
 
 	var output []string
 	// run the functions provided.
@@ -293,3 +294,45 @@ func (t *LoggerTest) TestInitLogFile() {
 	ExpectEq(backupFileCount, defaultLoggerFactory.logRotateConfig.BackupFileCount)
 	ExpectEq(true, defaultLoggerFactory.logRotateConfig.Compress)
 }
+
+func (t *LoggerTest) TestSetLogFormatToText() {
+	defaultLoggerFactory = &loggerFactory{
+		file:            nil,
+		level:           config.INFO, // setting log level to INFO by default
+		logRotateConfig: config.DefaultLogRotateConfig(),
+	}
+
+	testData := []struct {
+		format         string
+		expectedOutput string
+	}{
+		{
+			"text",
+			textInfoString,
+		},
+		{
+			"json",
+			jsonInfoString,
+		},
+		{
+			"",
+			jsonInfoString,
+		},
+	}
+
+	for _, test := range testData {
+		SetLogFormat(test.format)
+
+		AssertNe(nil, defaultLoggerFactory)
+		AssertNe(nil, defaultLogger)
+		ExpectEq(defaultLoggerFactory.format, test.format)
+		// Create a logger using defaultLoggerFactory that writes to buffer.
+		var buf bytes.Buffer
+		redirectLogsToGivenBuffer(&buf, defaultLoggerFactory.level)
+		Infof("www.infoExample.com")
+		output := buf.String()
+		// Compare expected and actual log.
+		expectedRegexp := regexp.MustCompile(test.expectedOutput)
+		ExpectTrue(expectedRegexp.MatchString(output))
+	}
+}

internal/logger/slog_helper.go

@@ -100,10 +100,10 @@ func addPrefixToMessage(a *slog.Attr, prefix string) {
 // time="08/09/2023 09:24:54.437193"
 func customiseTimeFormat(a *slog.Attr, format string) {
 	currTime := a.Value.Any().(time.Time).Round(0)
-	if format == "json" {
-		*a = slog.Group(timestampKey, secondsKey, currTime.Unix(), nanosKey, currTime.Nanosecond())
-	} else {
+	if format == textFormat {
 		a.Value = slog.StringValue(currTime.Round(0).Format("02/01/2006 03:04:05.000000"))
+	} else {
+		*a = slog.Group(timestampKey, secondsKey, currTime.Unix(), nanosKey, currTime.Nanosecond())
 	}
 }
 

main.go

@@ -223,6 +223,12 @@ func runCLIApp(c *cli.Context) (err error) {
 	config.OverrideWithLoggingFlags(mountConfig, flags.LogFile, flags.LogFormat,
 		flags.DebugFuse, flags.DebugGCS, flags.DebugMutex)
 
+	// Ideally this call to SetLogFormat (which internally creates a new defaultLogger)
+	// should be set as an else to the 'if flags.Foreground' check below, but currently
+	// that means the logs generated by resolveConfigFilePaths below don't honour
+	// the user-provided log-format.
+	logger.SetLogFormat(mountConfig.LogConfig.Format)
+
 	err = resolveConfigFilePaths(mountConfig)
 	if err != nil {
 		return fmt.Errorf("Resolving path: %w", err)