Beego/logs/console.go

// Copyright 2014 beego Author. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package logs

import (
	"encoding/json"
	"log"
	"os"
	"runtime"
	"time"
)

// brush is a color join function
type brush func(string) string

// newBrush return a fix color Brush
func newBrush(color string) brush {
	pre := "\033["
	reset := "\033[0m"
	return func(text string) string {
		return pre + color + "m" + text + reset
	}
}

var colors = []brush{
	newBrush("1;37"), // Emergency          white
	newBrush("1;36"), // Alert              cyan
	newBrush("1;35"), // Critical           magenta
	newBrush("1;31"), // Error              red
	newBrush("1;33"), // Warning            yellow
	newBrush("1;32"), // Notice             green
	newBrush("1;34"), // Informational      blue
	newBrush("1;34"), // Debug              blue
}

// consoleWriter implements LoggerInterface and writes messages to terminal.
type consoleWriter struct {
	lg       *log.Logger
	Level    int  `json:"level"`
	Colorful bool `json:"color"` //this filed is useful only when system's terminal supports color
}

// NewConsole create ConsoleWriter returning as LoggerInterface.
func NewConsole() Logger {
	cw := &consoleWriter{
		lg:       log.New(os.Stdout, "", 0),
		Level:    LevelDebug,
		Colorful: true,
	}
	return cw
}

// Init init console logger.
// jsonConfig like '{"level":LevelTrace}'.
func (c *consoleWriter) Init(jsonConfig string) error {
	if len(jsonConfig) == 0 {
		return nil
	}
	err := json.Unmarshal([]byte(jsonConfig), c)
	if runtime.GOOS == "windows" {
		c.Colorful = false
	}
	return err
}

// WriteMsg write message in console.
func (c *consoleWriter) WriteMsg(when time.Time, msg string, level int) error {
	if level > c.Level {
		return nil
	}
	msg = formatLogTime(when) + msg
	if c.Colorful {
		c.lg.Println(colors[level](msg))
	} else {
		c.lg.Println(msg)
	}
	return nil
}

// Destroy implementing method. empty.
func (c *consoleWriter) Destroy() {

}

// Flush implementing method. empty.
func (c *consoleWriter) Flush() {

}

func init() {
	Register("console", NewConsole)
}