Add structured logging

Author: maruschin

api/openapi.yaml

@@ -63,6 +63,8 @@ components:
           type: array
           items:
             type: string
+        structuredLog:
+          type: boolean
         logFile:
           type: string
         sysLogPrefix:

internal/conf/conf.go

@@ -152,6 +152,7 @@ type Conf struct {
 	// General
 	LogLevel            LogLevel        `json:"logLevel"`
 	LogDestinations     LogDestinations `json:"logDestinations"`
+	StructuredLog       bool            `json:"structuredLog"`
 	LogFile             string          `json:"logFile"`
 	SysLogPrefix        string          `json:"sysLogPrefix"`
 	ReadTimeout         Duration        `json:"readTimeout"`
@@ -312,6 +313,7 @@ func (conf *Conf) setDefaults() {
 	// General
 	conf.LogLevel = LogLevel(logger.Info)
 	conf.LogDestinations = LogDestinations{logger.DestinationStdout}
+	conf.StructuredLog = false
 	conf.LogFile = "mediamtx.log"
 	conf.SysLogPrefix = "mediamtx"
 	conf.ReadTimeout = 10 * Duration(time.Second)

internal/core/core.go

@@ -156,7 +156,7 @@ func New(args []string) (*Core, bool) {
 		done:           make(chan struct{}),
 	}
 
-	tempLogger, _ := logger.New(logger.Warn, []logger.Destination{logger.DestinationStdout}, "", "")
+	tempLogger, _ := logger.New(logger.Warn, []logger.Destination{logger.DestinationStdout}, "", "", false)
 
 	confPaths := append([]string(nil), defaultConfPaths...)
 	if runtime.GOOS != "windows" {
@@ -267,6 +267,7 @@ func (p *Core) createResources(initial bool) error {
 			p.conf.LogDestinations,
 			p.conf.LogFile,
 			p.conf.SysLogPrefix,
+			p.conf.StructuredLog,
 		)
 		if err != nil {
 			return err
@@ -690,7 +691,8 @@ func (p *Core) closeResources(newConf *conf.Conf, calledByAPI bool) {
 		newConf.LogLevel != p.conf.LogLevel ||
 		!reflect.DeepEqual(newConf.LogDestinations, p.conf.LogDestinations) ||
 		newConf.LogFile != p.conf.LogFile ||
-		newConf.SysLogPrefix != p.conf.SysLogPrefix
+		newConf.SysLogPrefix != p.conf.SysLogPrefix ||
+		newConf.StructuredLog != p.conf.StructuredLog
 
 	closeAuthManager := newConf == nil ||
 		newConf.AuthMethod != p.conf.AuthMethod ||

internal/logger/destination_stdout_structured.go

@@ -0,0 +1,33 @@
+package logger
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+)
+
+type destinationStdoutStructured struct {
+	buf bytes.Buffer
+}
+
+func newDestionationStdoutStructured() destination {
+	return &destinationStdoutStructured{}
+}
+
+func (d *destinationStdoutStructured) log(t time.Time, level Level, format string, args ...any) {
+	d.buf.Reset()
+	d.buf.WriteString(`{"ts":"`)
+	writeTime(&d.buf, t, false)
+	d.buf.WriteString(`","level":"`)
+	writeLevel(&d.buf, level, false)
+	d.buf.WriteString(`","msg":"`)
+	d.buf.WriteString(strconv.Quote(fmt.Sprintf(format, args...)))
+	d.buf.WriteString(`"}`)
+	d.buf.WriteByte('\n')
+	os.Stdout.Write(d.buf.Bytes()) //nolint:errcheck
+}
+
+func (d *destinationStdoutStructured) close() {
+}

internal/logger/logger.go

@@ -19,15 +19,19 @@ type Logger struct {
 }
 
 // New allocates a log handler.
-func New(level Level, destinations []Destination, filePath string, sysLogPrefix string) (*Logger, error) {
+func New(level Level, destinations []Destination, filePath string, sysLogPrefix string, structuredLog bool) (*Logger, error) {
 	lh := &Logger{
 		level: level,
 	}
 
 	for _, destType := range destinations {
 		switch destType {
 		case DestinationStdout:
-			lh.destinations = append(lh.destinations, newDestionationStdout())
+			if structuredLog {
+				lh.destinations = append(lh.destinations, newDestionationStdoutStructured())
+			} else {
+				lh.destinations = append(lh.destinations, newDestionationStdout())
+			}
 
 		case DestinationFile:
 			dest, err := newDestinationFile(filePath)

mediamtx.yml

@@ -10,6 +10,8 @@
 logLevel: info
 # Destinations of log messages; available values are "stdout", "file" and "syslog".
 logDestinations: [stdout]
+# If "stdout" in logDestination, use json for logs.
+structuredLog: no
 # If "file" is in logDestinations, this is the file which will receive the logs.
 logFile: mediamtx.log
 # If "syslog" is in logDestinations, use prefix for logs.