independent flag for json structured logging

- logjson flag remove logformat flag
- passed to eth Config
- logsystem not a field of Ethereum
- LogSystem does not need to expose GetLogLevel/SetLogLevel
- message struct just implements more generic LogMsg interface
- LogMsg is a fmt.Stringer with Level()
- jsonMsg ([]byte) implements LogMsg
- remove "raw" systems
- move level logic inside StdLogSystem
- logsystems only print their kind of msg: jsonLogSystem prints jsonMsg, StdLogSystem prints stdMsg

logger/log.go

@@ -18,7 +18,7 @@ func openLogFile(datadir string, filename string) *os.File {
 	return file
 }
 
-func New(datadir string, logFile string, logLevel int, logFormat string) LogSystem {
+func New(datadir string, logFile string, logLevel int) LogSystem {
 	var writer io.Writer
 	if logFile == "" {
 		writer = os.Stdout
@@ -27,14 +27,22 @@ func New(datadir string, logFile string, logLevel int, logFormat string) LogSyst
 	}
 
 	var sys LogSystem
-	switch logFormat {
-	case "raw":
-		sys = NewRawLogSystem(writer, 0, LogLevel(logLevel))
-	case "json":
-		sys = NewJsonLogSystem(writer, 0, LogLevel(logLevel))
-	default:
-		sys = NewStdLogSystem(writer, log.LstdFlags, LogLevel(logLevel))
-	}
+	sys = NewStdLogSystem(writer, log.LstdFlags, LogLevel(logLevel))
+	AddLogSystem(sys)
+
+	return sys
+}
+
+func NewJSONsystem(datadir string, logFile string) LogSystem {
+	var writer io.Writer
+	if logFile == "-" {
+		writer = os.Stdout
+	} else {
+		writer = openLogFile(datadir, logFile)
+	}
+
+	var sys LogSystem
+	sys = NewJsonLogSystem(writer)
 	AddLogSystem(sys)
 
 	return sys

logger/loggers.go

@@ -28,7 +28,6 @@ const (
 	InfoLevel
 	DebugLevel
 	DebugDetailLevel
-	JsonLevel = 1000
 )
 
 // A Logger prints messages prefixed by a given tag. It provides named
@@ -43,11 +42,11 @@ func NewLogger(tag string) *Logger {
 }
 
 func (logger *Logger) Sendln(level LogLevel, v ...interface{}) {
-	logMessageC <- message{level, logger.tag + fmt.Sprintln(v...)}
+	logMessageC <- stdMsg{level, logger.tag + fmt.Sprintln(v...)}
 }
 
 func (logger *Logger) Sendf(level LogLevel, format string, v ...interface{}) {
-	logMessageC <- message{level, logger.tag + fmt.Sprintf(format, v...)}
+	logMessageC <- stdMsg{level, logger.tag + fmt.Sprintf(format, v...)}
 }
 
 // Errorln writes a message with ErrorLevel.
@@ -129,6 +128,6 @@ func (logger *JsonLogger) LogJson(v JsonLog) {
 	}
 
 	jsontxt, _ := json.Marshal(obj)
-	logMessageC <- message{JsonLevel, string(jsontxt)}
+	logMessageC <- (jsonMsg(jsontxt))
 
 }

logger/loggers_test.go

@@ -15,9 +15,11 @@ type TestLogSystem struct {
 	level  LogLevel
 }
 
-func (ls *TestLogSystem) LogPrint(level LogLevel, msg string) {
+func (ls *TestLogSystem) LogPrint(msg LogMsg) {
 	ls.mutex.Lock()
-	ls.output += msg
+	if ls.level >= msg.Level() {
+		ls.output += msg.String()
+	}
 	ls.mutex.Unlock()
 }
 
@@ -47,9 +49,9 @@ type blockedLogSystem struct {
 	unblock chan struct{}
 }
 
-func (ls blockedLogSystem) LogPrint(level LogLevel, msg string) {
+func (ls blockedLogSystem) LogPrint(msg LogMsg) {
 	<-ls.unblock
-	ls.LogSystem.LogPrint(level, msg)
+	ls.LogSystem.LogPrint(msg)
 }
 
 func TestLoggerFlush(t *testing.T) {

logger/logsystem.go

@@ -9,9 +9,7 @@ import (
 // LogSystem is implemented by log output devices.
 // All methods can be called concurrently from multiple goroutines.
 type LogSystem interface {
-	GetLogLevel() LogLevel
-	SetLogLevel(i LogLevel)
-	LogPrint(LogLevel, string)
+	LogPrint(LogMsg)
 }
 
 // NewStdLogSystem creates a LogSystem that prints to the given writer.
@@ -26,8 +24,13 @@ type stdLogSystem struct {
 	level  uint32
 }
 
-func (t *stdLogSystem) LogPrint(level LogLevel, msg string) {
-	t.logger.Print(msg)
+func (t *stdLogSystem) LogPrint(msg LogMsg) {
+	stdmsg, ok := msg.(stdMsg)
+	if ok {
+		if t.GetLogLevel() >= stdmsg.Level() {
+			t.logger.Print(stdmsg.String())
+		}
+	}
 }
 
 func (t *stdLogSystem) SetLogLevel(i LogLevel) {
@@ -38,50 +41,20 @@ func (t *stdLogSystem) GetLogLevel() LogLevel {
 	return LogLevel(atomic.LoadUint32(&t.level))
 }
 
-// NewRawLogSystem creates a LogSystem that prints to the given writer without
-// adding extra information. Suitable for preformatted output
-func NewRawLogSystem(writer io.Writer, flags int, level LogLevel) LogSystem {
+// NewJSONLogSystem creates a LogSystem that prints to the given writer without
+// adding extra information irrespective of loglevel only if message is JSON type
+func NewJsonLogSystem(writer io.Writer) LogSystem {
 	logger := log.New(writer, "", 0)
-	return &rawLogSystem{logger, uint32(level)}
-}
-
-type rawLogSystem struct {
-	logger *log.Logger
-	level  uint32
-}
-
-func (t *rawLogSystem) LogPrint(level LogLevel, msg string) {
-	t.logger.Print(msg)
-}
-
-func (t *rawLogSystem) SetLogLevel(i LogLevel) {
-	atomic.StoreUint32(&t.level, uint32(i))
-}
-
-func (t *rawLogSystem) GetLogLevel() LogLevel {
-	return LogLevel(atomic.LoadUint32(&t.level))
-}
-
-// NewRawLogSystem creates a LogSystem that prints to the given writer without
-// adding extra information. Suitable for preformatted output
-func NewJsonLogSystem(writer io.Writer, flags int, level LogLevel) LogSystem {
-	logger := log.New(writer, "", 0)
-	return &jsonLogSystem{logger, uint32(level)}
+	return &jsonLogSystem{logger}
 }
 
 type jsonLogSystem struct {
 	logger *log.Logger
-	level  uint32
 }
 
-func (t *jsonLogSystem) LogPrint(level LogLevel, msg string) {
-	t.logger.Print(msg)
-}
-
-func (t *jsonLogSystem) SetLogLevel(i LogLevel) {
-	atomic.StoreUint32(&t.level, uint32(i))
-}
-
-func (t *jsonLogSystem) GetLogLevel() LogLevel {
-	return LogLevel(atomic.LoadUint32(&t.level))
+func (t *jsonLogSystem) LogPrint(msg LogMsg) {
+	jsonmsg, ok := msg.(jsonMsg)
+	if ok {
+		t.logger.Print(jsonmsg.String())
+	}
 }

logger/sys.go

@@ -1,16 +1,40 @@
 package logger
 
 import (
+	"fmt"
 	"sync"
 )
 
-type message struct {
+type stdMsg struct {
 	level LogLevel
 	msg   string
 }
 
+type jsonMsg []byte
+
+func (m jsonMsg) Level() LogLevel {
+	return 0
+}
+
+func (m jsonMsg) String() string {
+	return string(m)
+}
+
+type LogMsg interface {
+	Level() LogLevel
+	fmt.Stringer
+}
+
+func (m stdMsg) Level() LogLevel {
+	return m.level
+}
+
+func (m stdMsg) String() string {
+	return m.msg
+}
+
 var (
-	logMessageC = make(chan message)
+	logMessageC = make(chan LogMsg)
 	addSystemC  = make(chan LogSystem)
 	flushC      = make(chan chan struct{})
 	resetC      = make(chan chan struct{})
@@ -27,11 +51,11 @@ const sysBufferSize = 500
 func dispatchLoop() {
 	var (
 		systems  []LogSystem
-		systemIn []chan message
+		systemIn []chan LogMsg
 		systemWG sync.WaitGroup
 	)
 	bootSystem := func(sys LogSystem) {
-		in := make(chan message, sysBufferSize)
+		in := make(chan LogMsg, sysBufferSize)
 		systemIn = append(systemIn, in)
 		systemWG.Add(1)
 		go sysLoop(sys, in, &systemWG)
@@ -73,18 +97,9 @@ func dispatchLoop() {
 	}
 }
 
-func sysLoop(sys LogSystem, in <-chan message, wg *sync.WaitGroup) {
+func sysLoop(sys LogSystem, in <-chan LogMsg, wg *sync.WaitGroup) {
 	for msg := range in {
-		switch sys.(type) {
-		case *jsonLogSystem:
-			if msg.level == JsonLevel {
-				sys.LogPrint(msg.level, msg.msg)
-			}
-		default:
-			if sys.GetLogLevel() >= msg.level {
-				sys.LogPrint(msg.level, msg.msg)
-			}
-		}
+		sys.LogPrint(msg)
 	}
 	wg.Done()
 }