minio/cmd/logger-syslog-hook_nix.go

// +build !windows

/*
 * Minio Cloud Storage, (C) 2015, 2016 Minio, Inc.
 *
 * 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 cmd

import (
	"fmt"
	"log/syslog"

	"github.com/Sirupsen/logrus"
)

type syslogLogger struct {
	Enable bool   `json:"enable"`
	Addr   string `json:"address"`
	Level  string `json:"level"`
}

// syslogHook to send logs via syslog.
type syslogHook struct {
	writer        *syslog.Writer
	syslogNetwork string
	syslogRaddr   string
}

// enableSyslogLogger - enable logger at raddr.
func enableSyslogLogger(raddr string) {
	syslogHook, err := newSyslog("udp", raddr, syslog.LOG_ERR, "MINIO")
	fatalIf(err, "Unable to initialize syslog logger.")

	log.Hooks.Add(syslogHook)               // Add syslog hook.
	log.Formatter = &logrus.JSONFormatter{} // JSON formatted log.
	log.Level = logrus.ErrorLevel           // Minimum log level.
}

// newSyslog - Creates a hook to be added to an instance of logger.
func newSyslog(network, raddr string, priority syslog.Priority, tag string) (*syslogHook, error) {
	w, err := syslog.Dial(network, raddr, priority, tag)
	return &syslogHook{w, network, raddr}, err
}

// Fire - fire the log event
func (hook *syslogHook) Fire(entry *logrus.Entry) error {
	line, err := entry.String()
	if err != nil {
		return fmt.Errorf("Unable to read entry, %v", err)
	}
	switch entry.Level {
	case logrus.PanicLevel:
		return hook.writer.Crit(line)
	case logrus.FatalLevel:
		return hook.writer.Crit(line)
	case logrus.ErrorLevel:
		return hook.writer.Err(line)
	default:
		return nil
	}
}

// Levels -
func (hook *syslogHook) Levels() []logrus.Level {
	return []logrus.Level{
		logrus.PanicLevel,
		logrus.FatalLevel,
		logrus.ErrorLevel,
	}
}