Move log into common

common/log/log.go

@@ -0,0 +1,53 @@
+package log
+
+import (
+	"errors"
+	"fmt"
+	"log"
+)
+
+const (
+	DebugLevel   = LogLevel(0)
+	InfoLevel    = LogLevel(1)
+	WarningLevel = LogLevel(2)
+	ErrorLevel   = LogLevel(3)
+)
+
+var logLevel = WarningLevel
+
+type LogLevel int
+
+func SetLogLevel(level LogLevel) {
+	logLevel = level
+}
+
+func writeLog(level LogLevel, prefix, format string, v ...interface{}) string {
+	if level < logLevel {
+		return ""
+	}
+	var data string
+	if v == nil || len(v) == 0 {
+		data = format
+	} else {
+		data = fmt.Sprintf(format, v...)
+	}
+	log.Print(prefix + data)
+	return data
+}
+
+func Debug(format string, v ...interface{}) {
+	writeLog(DebugLevel, "[Debug]", format, v...)
+}
+
+func Info(format string, v ...interface{}) {
+	writeLog(InfoLevel, "[Info]", format, v...)
+}
+
+func Warning(format string, v ...interface{}) {
+	writeLog(WarningLevel, "[Warning]", format, v...)
+}
+
+func Error(format string, v ...interface{}) error {
+	data := writeLog(ErrorLevel, "[Error]", format, v...)
+	return errors.New(data)
+}