boulder/log/audit-logger.go

// Copyright 2015 ISRG.  All rights reserved
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

package log

import (
	"errors"
	"fmt"
	"log/syslog"
	"os"
	"sync"

	"github.com/letsencrypt/boulder/Godeps/_workspace/src/github.com/cactus/go-statsd-client/statsd"
)

// singleton defines the object of a Singleton pattern
type singleton struct {
	once sync.Once
	log  *AuditLogger
}

// _Singleton is the single AuditLogger entity in memory
var _Singleton singleton

// The constant used to identify audit-specific messages
const auditTag = "[AUDIT]"

// AuditLogger is a System Logger with additional audit-specific methods.
// In addition to all the standard syslog.Writer methods from
// http://golang.org/pkg/log/syslog/#Writer, you can also call
//   auditLogger.Audit(msg string)
// to send a message as an audit event.
type AuditLogger struct {
	*syslog.Writer
	Stats statsd.Statter
}

// Dial establishes a connection to the log daemon by passing through
// the parameters to the syslog.Dial method.
// See http://golang.org/pkg/log/syslog/#Dial
func Dial(network, raddr string, tag string, stats statsd.Statter) (*AuditLogger, error) {
	syslogger, err := syslog.Dial(network, raddr, syslog.LOG_INFO|syslog.LOG_LOCAL0, tag)
	if err != nil {
		return nil, err
	}
	return NewAuditLogger(syslogger, stats)
}

// NewAuditLogger constructs an Audit Logger that decorates a normal
// System Logger. All methods in log/syslog continue to work.
func NewAuditLogger(log *syslog.Writer, stats statsd.Statter) (*AuditLogger, error) {
	if log == nil {
		return nil, errors.New("Attempted to use a nil System Logger.")
	}
	return &AuditLogger{log, stats}, nil
}

// initializeAuditLogger should only be used in unit tests. Failures in this
// method are unlikely as the defaults are safe, and they are also
// of minimal consequence during unit testing -- logs get printed to stdout
// even if syslog is missing.
func initializeAuditLogger() {
	stats, _ := statsd.NewNoopClient(nil)
	audit, _ := Dial("", "", "default", stats)
	audit.Notice("Using default logging configuration.")

	SetAuditLogger(audit)
}

// SetAuditLogger configures the singleton audit logger. This method
// must only be called once, and before calling GetAuditLogger the
// first time.
func SetAuditLogger(logger *AuditLogger) (err error) {
	if _Singleton.log != nil {
		err = errors.New("You may not call SetAuditLogger after it has already been implicitly or explicitly set.")
		_Singleton.log.WarningErr(err)
	} else {
		_Singleton.log = logger
	}
	return
}

// GetAuditLogger obtains the singleton audit logger. If SetAuditLogger
// has not been called first, this method initializes with basic defaults.
// The basic defaults cannot error, and subequent access to an already-set
// AuditLogger also cannot error, so this method is error-safe.
func GetAuditLogger() *AuditLogger {
	_Singleton.once.Do(func() {
		if _Singleton.log == nil {
			initializeAuditLogger()
		}
	})

	return _Singleton.log
}

// Audit sends a NOTICE-severity message that is prefixed with the
// audit tag, for special handling at the upstream system logger.
func (log *AuditLogger) Audit(msg string) (err error) {
	fmt.Println(msg)
	err = log.Notice(fmt.Sprintf("%s %s", auditTag, msg))

	log.Stats.Inc("Logging.Audit", 1, 1.0)

	return
}

// Audit can format an error for auditing; it does so at ERR level.
func (log *AuditLogger) AuditErr(msg error) (err error) {
	fmt.Println(msg)
	err = log.Err(fmt.Sprintf("%s %s", auditTag, msg))

	log.Stats.Inc("Logging.Audit", 1, 1.0)

	return
}

// Warning formats an error for the Warn level.
func (log *AuditLogger) WarningErr(msg error) (err error) {
	fmt.Println(msg)
	err = log.Warning(fmt.Sprintf("%s", msg))

	return
}

func (log *AuditLogger) Alert(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Alert", 1, 1.0)
	return log.Writer.Alert(msg)
}

func (log *AuditLogger) Crit(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Crit", 1, 1.0)
	return log.Writer.Crit(msg)
}

func (log *AuditLogger) Debug(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Debug", 1, 1.0)
	return log.Writer.Debug(msg)
}

func (log *AuditLogger) Emerg(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Emerg", 1, 1.0)
	return log.Writer.Emerg(msg)
}

func (log *AuditLogger) Err(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Err", 1, 1.0)
	return log.Writer.Err(msg)
}

func (log *AuditLogger) Info(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Info", 1, 1.0)
	return log.Writer.Info(msg)
}

func (log *AuditLogger) Warning(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Warning", 1, 1.0)
	return log.Writer.Warning(msg)
}

func (log *AuditLogger) Notice(msg string) (err error) {
	fmt.Println(msg)
	log.Stats.Inc("Logging.Notice", 1, 1.0)
	return log.Writer.Notice(msg)
}

const EMERGENCY_RETVAL = 13

func (log *AuditLogger) EmergencyExit(msg string) {
	// Some errors may be serious enough to trigger an immediate Boulder
	// shutdown.  This function will provide the necessary housekeeping.
	// Currently, make an emergency log entry and exit; the Activity Monitor
	// should notice the Emerg level event and shut down all components.
	log.Emerg(msg)
	os.Exit(EMERGENCY_RETVAL)
}