all: improve the method of import for internal packages

1. Change directory structure and Makefile to let GOPATH=`pwd`, so wherever the project directory is, just use make to build.

src/frp/utils/log/log.go

@@ -0,0 +1,64 @@
+package log
+
+import (
+	"github.com/astaxie/beego/logs"
+)
+
+var Log *logs.BeeLogger
+
+func init() {
+	Log = logs.NewLogger(1000)
+	Log.EnableFuncCallDepth(true)
+	Log.SetLogFuncCallDepth(Log.GetLogFuncCallDepth() + 1)
+}
+
+func InitLog(logWay string, logFile string, logLevel string) {
+	SetLogFile(logWay, logFile)
+	SetLogLevel(logLevel)
+}
+
+// logWay: such as file or console
+func SetLogFile(logWay string, logFile string) {
+	if logWay == "console" {
+		Log.SetLogger("console", "")
+	} else {
+		Log.SetLogger("file", `{"filename": "`+logFile+`"}`)
+	}
+}
+
+// value: error, warning, info, debug
+func SetLogLevel(logLevel string) {
+	level := 4 // warning
+
+	switch logLevel {
+	case "error":
+		level = 3
+	case "warn":
+		level = 4
+	case "info":
+		level = 6
+	case "debug":
+		level = 7
+	default:
+		level = 4
+	}
+
+	Log.SetLevel(level)
+}
+
+// wrap log
+func Error(format string, v ...interface{}) {
+	Log.Error(format, v...)
+}
+
+func Warn(format string, v ...interface{}) {
+	Log.Warn(format, v...)
+}
+
+func Info(format string, v ...interface{}) {
+	Log.Info(format, v...)
+}
+
+func Debug(format string, v ...interface{}) {
+	Log.Debug(format, v...)
+}