Refactor Logger (#13294)

Refactor Logger to make a logger interface and make it possible to
wrap loggers for specific purposes.

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/log/multichannel.go

@@ -0,0 +1,98 @@
+// Copyright 2020 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package log
+
+import (
+	"fmt"
+	"runtime"
+	"strings"
+	"time"
+)
+
+// MultiChannelledLogger is default logger in the Gitea application.
+// it can contain several providers and log message into all providers.
+type MultiChannelledLogger struct {
+	LevelLoggerLogger
+	*MultiChannelledLog
+	bufferLength int64
+}
+
+// newLogger initializes and returns a new logger.
+func newLogger(name string, buffer int64) *MultiChannelledLogger {
+	l := &MultiChannelledLogger{
+		MultiChannelledLog: NewMultiChannelledLog(name, buffer),
+		bufferLength:       buffer,
+	}
+	l.LevelLogger = l
+	return l
+}
+
+// SetLogger sets new logger instance with given logger provider and config.
+func (l *MultiChannelledLogger) SetLogger(name, provider, config string) error {
+	eventLogger, err := NewChannelledLog(name, provider, config, l.bufferLength)
+	if err != nil {
+		return fmt.Errorf("Failed to create sublogger (%s): %v", name, err)
+	}
+
+	l.MultiChannelledLog.DelLogger(name)
+
+	err = l.MultiChannelledLog.AddLogger(eventLogger)
+	if err != nil {
+		if IsErrDuplicateName(err) {
+			return fmt.Errorf("Duplicate named sublogger %s %v", name, l.MultiChannelledLog.GetEventLoggerNames())
+		}
+		return fmt.Errorf("Failed to add sublogger (%s): %v", name, err)
+	}
+
+	return nil
+}
+
+// DelLogger deletes a sublogger from this logger.
+func (l *MultiChannelledLogger) DelLogger(name string) (bool, error) {
+	return l.MultiChannelledLog.DelLogger(name), nil
+}
+
+// Log msg at the provided level with the provided caller defined by skip (0 being the function that calls this function)
+func (l *MultiChannelledLogger) Log(skip int, level Level, format string, v ...interface{}) error {
+	if l.GetLevel() > level {
+		return nil
+	}
+	caller := "?()"
+	pc, filename, line, ok := runtime.Caller(skip + 1)
+	if ok {
+		// Get caller function name.
+		fn := runtime.FuncForPC(pc)
+		if fn != nil {
+			caller = fn.Name() + "()"
+		}
+	}
+	msg := format
+	if len(v) > 0 {
+		msg = ColorSprintf(format, v...)
+	}
+	stack := ""
+	if l.GetStacktraceLevel() <= level {
+		stack = Stack(skip + 1)
+	}
+	return l.SendLog(level, caller, strings.TrimPrefix(filename, prefix), line, msg, stack)
+}
+
+// SendLog sends a log event at the provided level with the information given
+func (l *MultiChannelledLogger) SendLog(level Level, caller, filename string, line int, msg string, stack string) error {
+	if l.GetLevel() > level {
+		return nil
+	}
+	event := &Event{
+		level:      level,
+		caller:     caller,
+		filename:   filename,
+		line:       line,
+		msg:        msg,
+		time:       time.Now(),
+		stacktrace: stack,
+	}
+	l.LogEvent(event)
+	return nil
+}