1 files changed, 60 insertions, 0 deletions
diff --git a/logger/logsystem.go b/logger/logsystem.go
new file mode 100644
index 000000000..4dadb126e
--- /dev/null
+++ b/logger/logsystem.go
@@ -0,0 +1,60 @@
+package logger
+
+import (
+	"io"
+	"log"
+	"sync/atomic"
+)
+
+// LogSystem is implemented by log output devices.
+// All methods can be called concurrently from multiple goroutines.
+type LogSystem interface {
+	LogPrint(LogMsg)
+}
+
+// NewStdLogSystem creates a LogSystem that prints to the given writer.
+// The flag values are defined package log.
+func NewStdLogSystem(writer io.Writer, flags int, level LogLevel) *StdLogSystem {
+	logger := log.New(writer, "", flags)
+	return &StdLogSystem{logger, uint32(level)}
+}
+
+type StdLogSystem struct {
+	logger *log.Logger
+	level  uint32
+}
+
+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) {
+	atomic.StoreUint32(&t.level, uint32(i))
+}
+
+func (t *StdLogSystem) GetLogLevel() LogLevel {
+	return LogLevel(atomic.LoadUint32(&t.level))
+}
+
+// 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 &jsonLogSystem{logger}
+}
+
+type jsonLogSystem struct {
+	logger *log.Logger
+}
+
+func (t *jsonLogSystem) LogPrint(msg LogMsg) {
+	jsonmsg, ok := msg.(jsonMsg)
+	if ok {
+		t.logger.Print(jsonmsg.String())
+	}
+}