blob: 3eb5353e9a9b8ae73854d883ac0f73787942267e [file] [log] [blame]
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package syslog provides a simple interface to the system log service. It
// can send messages to the syslog daemon using UNIX domain sockets, UDP, or
// TCP connections.
package syslog
import (
"errors"
"fmt"
"log"
"net"
"os"
)
type Priority int
const (
// From /usr/include/sys/syslog.h.
// These are the same on Linux, BSD, and OS X.
LOG_EMERG Priority = iota
LOG_ALERT
LOG_CRIT
LOG_ERR
LOG_WARNING
LOG_NOTICE
LOG_INFO
LOG_DEBUG
)
// A Writer is a connection to a syslog server.
type Writer struct {
priority Priority
prefix string
conn serverConn
}
type serverConn interface {
writeBytes(p Priority, prefix string, b []byte) (int, error)
writeString(p Priority, prefix string, s string) (int, error)
close() error
}
type netConn struct {
conn net.Conn
}
// New establishes a new connection to the system log daemon.
// Each write to the returned writer sends a log message with
// the given priority and prefix.
func New(priority Priority, prefix string) (w *Writer, err error) {
return Dial("", "", priority, prefix)
}
// Dial establishes a connection to a log daemon by connecting
// to address raddr on the network net.
// Each write to the returned writer sends a log message with
// the given priority and prefix.
func Dial(network, raddr string, priority Priority, prefix string) (w *Writer, err error) {
if prefix == "" {
prefix = os.Args[0]
}
var conn serverConn
if network == "" {
conn, err = unixSyslog()
} else {
var c net.Conn
c, err = net.Dial(network, raddr)
conn = netConn{c}
}
return &Writer{priority, prefix, conn}, err
}
// Write sends a log message to the syslog daemon.
func (w *Writer) Write(b []byte) (int, error) {
if w.priority > LOG_DEBUG || w.priority < LOG_EMERG {
return 0, errors.New("log/syslog: invalid priority")
}
return w.conn.writeBytes(w.priority, w.prefix, b)
}
func (w *Writer) writeString(p Priority, s string) (int, error) {
return w.conn.writeString(p, w.prefix, s)
}
func (w *Writer) Close() error { return w.conn.close() }
// Emerg logs a message using the LOG_EMERG priority.
func (w *Writer) Emerg(m string) (err error) {
_, err = w.writeString(LOG_EMERG, m)
return err
}
// Alert logs a message using the LOG_ALERT priority.
func (w *Writer) Alert(m string) (err error) {
_, err = w.writeString(LOG_ALERT, m)
return err
}
// Crit logs a message using the LOG_CRIT priority.
func (w *Writer) Crit(m string) (err error) {
_, err = w.writeString(LOG_CRIT, m)
return err
}
// Err logs a message using the LOG_ERR priority.
func (w *Writer) Err(m string) (err error) {
_, err = w.writeString(LOG_ERR, m)
return err
}
// Warning logs a message using the LOG_WARNING priority.
func (w *Writer) Warning(m string) (err error) {
_, err = w.writeString(LOG_WARNING, m)
return err
}
// Notice logs a message using the LOG_NOTICE priority.
func (w *Writer) Notice(m string) (err error) {
_, err = w.writeString(LOG_NOTICE, m)
return err
}
// Info logs a message using the LOG_INFO priority.
func (w *Writer) Info(m string) (err error) {
_, err = w.writeString(LOG_INFO, m)
return err
}
// Debug logs a message using the LOG_DEBUG priority.
func (w *Writer) Debug(m string) (err error) {
_, err = w.writeString(LOG_DEBUG, m)
return err
}
func (n netConn) writeBytes(p Priority, prefix string, b []byte) (int, error) {
_, err := fmt.Fprintf(n.conn, "<%d>%s: %s\n", p, prefix, b)
if err != nil {
return 0, err
}
return len(b), nil
}
func (n netConn) writeString(p Priority, prefix string, s string) (int, error) {
_, err := fmt.Fprintf(n.conn, "<%d>%s: %s\n", p, prefix, s)
if err != nil {
return 0, err
}
return len(s), nil
}
func (n netConn) close() error {
return n.conn.Close()
}
// NewLogger creates a log.Logger whose output is written to
// the system log service with the specified priority. The logFlag
// argument is the flag set passed through to log.New to create
// the Logger.
func NewLogger(p Priority, logFlag int) (*log.Logger, error) {
s, err := New(p, "")
if err != nil {
return nil, err
}
return log.New(s, "", logFlag), nil
}