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/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())
+	}
 }