add json format support for traefik logs

cmd/traefik/configuration.go

@@ -153,6 +153,12 @@ func NewTraefikDefaultPointersConfiguration() *TraefikConfiguration {
 	var defaultEureka eureka.Provider
 	defaultEureka.Delay = "30s"
 
+	// default TraefikLog
+	defaultTraefikLog := types.TraefikLog{
+		Format:   "common",
+		FilePath: "",
+	}
+
 	// default AccessLog
 	defaultAccessLog := types.AccessLog{
 		Format:   accesslog.CommonFormat,
@@ -177,6 +183,7 @@ func NewTraefikDefaultPointersConfiguration() *TraefikConfiguration {
 		DynamoDB:      &defaultDynamoDB,
 		Retry:         &configuration.Retry{},
 		HealthCheck:   &configuration.HealthCheckConfig{},
+		TraefikLog:    &defaultTraefikLog,
 		AccessLog:     &defaultAccessLog,
 	}
 

cmd/traefik/traefik.go

@@ -265,15 +265,36 @@ func run(globalConfiguration *configuration.GlobalConfiguration) {
 		log.Error("Error getting level", err)
 	}
 	log.SetLevel(level)
-	if len(globalConfiguration.TraefikLogsFile) > 0 {
-		dir := filepath.Dir(globalConfiguration.TraefikLogsFile)
+
+	logFile := globalConfiguration.TraefikLogsFile
+	if len(logFile) > 0 {
+		log.Warn("top-level traefiklogsfile has been deprecated -- please use traefiklog.filepath")
+	}
+	if globalConfiguration.TraefikLog != nil && len(globalConfiguration.TraefikLog.FilePath) > 0 {
+		logFile = globalConfiguration.TraefikLog.FilePath
+	}
+
+	var formatter logrus.Formatter
+	if globalConfiguration.TraefikLog != nil && globalConfiguration.TraefikLog.Format == "json" {
+		formatter = &logrus.JSONFormatter{}
+	} else {
+		disableColors := false
+		if len(logFile) > 0 {
+			disableColors = true
+		}
+		formatter = &logrus.TextFormatter{DisableColors: disableColors, FullTimestamp: true, DisableSorting: true}
+	}
+	log.SetFormatter(formatter)
+
+	if len(logFile) > 0 {
+		dir := filepath.Dir(logFile)
 
 		err := os.MkdirAll(dir, 0755)
 		if err != nil {
 			log.Errorf("Failed to create log path %s: %s", dir, err)
 		}
 
-		err = log.OpenFile(globalConfiguration.TraefikLogsFile)
+		err = log.OpenFile(logFile)
 		defer func() {
 			if err := log.CloseFile(); err != nil {
 				log.Error("Error closing log", err)
@@ -281,12 +302,9 @@ func run(globalConfiguration *configuration.GlobalConfiguration) {
 		}()
 		if err != nil {
 			log.Error("Error opening file", err)
-		} else {
-			log.SetFormatter(&logrus.TextFormatter{DisableColors: true, FullTimestamp: true, DisableSorting: true})
 		}
-	} else {
-		log.SetFormatter(&logrus.TextFormatter{FullTimestamp: true, DisableSorting: true})
 	}
+
 	jsonConf, _ := json.Marshal(globalConfiguration)
 	log.Infof("Traefik version %s built on %s", version.Version, version.BuildDate)
 

configuration/configuration.go

@@ -47,7 +47,8 @@ type GlobalConfiguration struct {
 	CheckNewVersion           bool                    `description:"Periodically check if a new version has been released"`
 	AccessLogsFile            string                  `description:"(Deprecated) Access logs file"` // Deprecated
 	AccessLog                 *types.AccessLog        `description:"Access log settings"`
-	TraefikLogsFile           string                  `description:"Traefik logs file. Stdout is used when omitted or empty"`
+	TraefikLogsFile           string                  `description:"(Deprecated) Traefik logs file. Stdout is used when omitted or empty"` // Deprecated
+	TraefikLog                *types.TraefikLog       `description:"Traefik log settings"`
 	LogLevel                  string                  `short:"l" description:"Log level"`
 	EntryPoints               EntryPoints             `description:"Entrypoints definition using format: --entryPoints='Name:http Address::8000 Redirect.EntryPoint:https' --entryPoints='Name:https Address::4442 TLS:tests/traefik.crt,tests/traefik.key;prod/traefik.crt,prod/traefik.key'"`
 	Cluster                   *types.Cluster          `description:"Enable clustering"`

docs/configuration/commons.md

@@ -152,6 +152,11 @@ constraints = ["tag==api", "tag!=v*-beta"]
 ```toml
 # Traefik logs file
 # If not defined, logs to stdout
+#
+# DEPRECATED - see [traefikLog] lower down
+# In case both traefikLogsFile and traefikLog.filePath are specified, the latter will take precedence.
+# Optional
+#
 traefikLogsFile = "log/traefik.log"
 
 # Log level
@@ -165,6 +170,23 @@ traefikLogsFile = "log/traefik.log"
 logLevel = "ERROR"
 ```
 
+## Traefik Logs
+
+By default the Traefik log is written to stdout in text format.
+
+To write the logs into a logfile specify the `filePath`.
+```toml
+[traefikLog]
+  filePath = "/path/to/traefik.log"
+```
+
+To write JSON format logs, specify `json` as the format:
+```toml
+[traefikLog]
+  filePath = "/path/to/traefik.log"
+  format   = "json"
+```
+
 ### Access Logs
 
 Access logs are written when `[accessLog]` is defined.

traefik.sample.toml

@@ -9,13 +9,6 @@
 #
 # debug = true
 
-# Traefik logs file
-# If not defined, logs to stdout
-#
-# Optional
-#
-# traefikLogsFile = "log/traefik.log"
-
 # Log level
 #
 # Optional
@@ -39,6 +32,28 @@
     [entryPoints.http]
     address = ":80"
 
+# Traefik logs
+# Enabled by default and log to stdout
+#
+# Optional
+#
+# [traefikLog]
+
+# Sets the filepath for the traefik log. If not specified, stdout will be used.
+# Intermediate directories are created if necessary.
+#
+# Optional
+# Default: os.Stdout
+#
+# filePath = "log/traefik.log"
+
+# Format is either "json" or "common".
+#
+# Optional
+# Default: "common"
+#
+# format = "common"
+
 # Enable access logs
 # By default it will write to stdout and produce logs in the textual
 # Common Log Format (CLF), extended with additional fields.

types/types.go

@@ -412,6 +412,12 @@ func (b *Buckets) SetValue(val interface{}) {
 	*b = Buckets(val.(Buckets))
 }
 
+// TraefikLog holds the configuration settings for the traefik logger.
+type TraefikLog struct {
+	FilePath string `json:"file,omitempty" description:"Traefik log file path. Stdout is used when omitted or empty"`
+	Format   string `json:"format,omitempty" description:"Traefik log format: json | common"`
+}
+
 // AccessLog holds the configuration settings for the access logger (middlewares/accesslog).
 type AccessLog struct {
 	FilePath string `json:"file,omitempty" description:"Access log file path. Stdout is used when omitted or empty"`