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Merge pull request #25 from RadhiFadlillah/master
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 Add method for setting default file or writer
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@rifflock
rifflock committed Dec 19, 2017
2 parents 1e68690 + 8299919 commit 1fdc019
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82 changes: 57 additions & 25 deletions README.md
View file
@@ -1,32 +1,39 @@
# Local Filesystem Hook for Logrus

Sometimes developers like to write directly to a file on the filesystem. This is a hook for [logrus](https://github.com/Sirupsen/logrus) designed to allow users to do just that. The log levels are dynamic at instantiation of the hook, so it is capable of logging at some or all levels.
[![GoDoc](https://godoc.org/github.com/rifflock/lfshook?status.svg)](http://godoc.org/github.com/rifflock/lfshook)

Sometimes developers like to write directly to a file on the filesystem. This is a hook for [`logrus`](https://github.com/sirupsen/logrus) which designed to allow users to do that. The log levels are dynamic at instantiation of the hook, so it is capable of logging at some or all levels.

## Example
```go
import (
log "github.com/sirupsen/logrus"
"github.com/rifflock/lfshook"
"github.com/sirupsen/logrus"
)

var Log *log.Logger
var Log *logrus.Logger

func NewLogger( config map[string]interface{} ) *log.Logger {
func NewLogger() *logrus.Logger {
if Log != nil {
return Log
}

Log = log.New()
Log.Hooks.Add(lfshook.NewHook(lfshook.PathMap{
log.InfoLevel : "/var/log/info.log",
log.ErrorLevel : "/var/log/error.log",
}, &log.JSONFormatter{}))
pathMap := lfshook.PathMap{
logrus.InfoLevel: "/var/log/info.log",
logrus.ErrorLevel: "/var/log/error.log",
}


Log.Hooks.Add(lfshook.NewHook(
pathMap,
&logrus.JSONFormatter{},
))
return Log
}
```

### Formatters
lfshook will strip colors from any TextFormatter type formatters when writing to local file, because the color codes don't look so great.
`lfshook` will strip colors from any `TextFormatter` type formatters when writing to local file, because the color codes don't look great in file.

If no formatter is provided via `lfshook.NewHook`, a default text formatter will be used.

Expand All @@ -35,21 +42,46 @@ In order to enable automatic log rotation it's possible to provide an io.Writer
In combination with pakages like [go-file-rotatelogs](https://github.com/lestrrat/go-file-rotatelogs) log rotation can easily be achieved.

```go
import "github.com/lestrrat/go-file-rotatelogs"

path := "/var/log/go.log"
writer := rotatelogs.NewRotateLogs(
path + ".%Y%m%d%H%M",
rotatelogs.WithLinkName(path),
rotatelogs.WithMaxAge(time.Duration(86400) * time.Second),
rotatelogs.WithRotationTime(time.Duration(604800) * time.Second),
)

log.Hooks.Add(lfshook.NewHook(lfshook.WriterMap{
logrus.InfoLevel: writer,
logrus.ErrorLevel: writer,
}, nil))
package main

import (
"github.com/lestrrat/go-file-rotatelogs"
"github.com/rifflock/lfshook"
"github.com/sirupsen/logrus"
)

var Log *logrus.Logger

func NewLogger() *logrus.Logger {
if Log != nil {
return Log
}

path := "/var/log/go.log"
writer := rotatelogs.NewRotateLogs(
path+".%Y%m%d%H%M",
rotatelogs.WithLinkName(path),
rotatelogs.WithMaxAge(time.Duration(86400)*time.Second),
rotatelogs.WithRotationTime(time.Duration(604800)*time.Second),
)

logrus.Hooks.Add(lfshook.NewHook(
lfshook.WriterMap{
logrus.InfoLevel: writer,
logrus.ErrorLevel: writer,
},
&logrus.JSONFormatter,
))

Log = logrus.New()
Log.Hooks.Add(lfshook.NewHook(
pathMap,
&logrus.JSONFormatter{},
))

return Log
}
```

### Note:
Whichever user is running the go application must have read/write permissions to the log files selected, or if the files do not yet exists, then to the directory in which the files will be created.
User who run the go application must have read/write permissions to the selected log files. If the files do not exists yet, then user must have permission to the target directory.
153 changes: 94 additions & 59 deletions lfshook.go
View file
@@ -1,107 +1,136 @@
// Package LFShook allows users to write to the logfiles using logrus.
// Package lfshook is hook for sirupsen/logrus that used for writing the logs to local files.
package lfshook

import (
"fmt"
"github.com/sirupsen/logrus"
"io"
"log"
"os"
"path/filepath"
"reflect"
"sync"

"github.com/sirupsen/logrus"
)

// We are logging to file, strip colors to make the output more readable
// We are logging to file, strip colors to make the output more readable.
var defaultFormatter = &logrus.TextFormatter{DisableColors: true}

// Map for linking a log level to a log file
// Multiple levels may share a file, but multiple files may not be used for one level
// PathMap is map for mapping a log level to a file's path.
// Multiple levels may share a file, but multiple files may not be used for one level.
type PathMap map[logrus.Level]string

// Alternatively map a log level to an io.Writer
// WriterMap is map for mapping a log level to an io.Writer.
// Multiple levels may share a writer, but multiple writers may not be used for one level.
type WriterMap map[logrus.Level]io.Writer

// Hook to handle writing to local log files.
type lfsHook struct {
// LfsHook is a hook to handle writing to local log files.
type LfsHook struct {
paths PathMap
writer WriterMap
writers WriterMap
levels []logrus.Level
lock *sync.Mutex
formatter logrus.Formatter

defaultPath string
defaultWriter io.Writer
hasDefaultPath bool
hasDefaultWriter bool
}

// Given a map with keys equal to log levels.
// We can generate our levels handled on the fly, and write to a specific file for each level.
// We can also write to the same file for all levels. They just need to be specified.
func NewHook(levelMap interface{}, userFormatter logrus.Formatter) *lfsHook {
var formatter logrus.Formatter
if userFormatter != nil {
formatter = userFormatter
} else {
formatter = defaultFormatter
}
hook := &lfsHook{
lock: new(sync.Mutex),
formatter: formatter,
// NewHook returns new LFS hook.
// Output can be a string, io.Writer, WriterMap or PathMap.
// If using io.Writer or WriterMap, user is responsible for closing the used io.Writer.
func NewHook(output interface{}, formatter logrus.Formatter) *LfsHook {
hook := &LfsHook{
lock: new(sync.Mutex),
}

switch levelMap.(type) {
hook.SetFormatter(formatter)

switch output.(type) {
case string:
hook.SetDefaultPath(output.(string))
break
case io.Writer:
hook.SetDefaultWriter(output.(io.Writer))
break
case PathMap:
hook.paths = levelMap.(PathMap)
for level := range levelMap.(PathMap) {
hook.paths = output.(PathMap)
for level := range output.(PathMap) {
hook.levels = append(hook.levels, level)
}
break
case WriterMap:
hook.writer = levelMap.(WriterMap)
for level := range levelMap.(WriterMap) {
hook.writers = output.(WriterMap)
for level := range output.(WriterMap) {
hook.levels = append(hook.levels, level)
}
break
default:
panic(fmt.Sprintf("unsupported level map type: %s", reflect.TypeOf(levelMap)))
panic(fmt.Sprintf("unsupported level map type: %v", reflect.TypeOf(output)))
}

return hook
}

// Replace the color stripped default formatter with a custom formatter
func (hook *lfsHook) SetFormatter(formatter logrus.Formatter) {
// SetFormatter sets the format that will be used by hook.
// If using text formatter, this method will disable color output to make the log file more readable.
func (hook *LfsHook) SetFormatter(formatter logrus.Formatter) {
if formatter == nil {
formatter = defaultFormatter
} else {
switch formatter.(type) {
case *logrus.TextFormatter:
textFormatter := formatter.(*logrus.TextFormatter)
textFormatter.DisableColors = true
}
}

hook.formatter = formatter
}

switch hook.formatter.(type) {
case *logrus.TextFormatter:
textFormatter := hook.formatter.(*logrus.TextFormatter)
textFormatter.DisableColors = true
}
// SetDefaultPath sets default path for levels that don't have any defined output path.
func (hook *LfsHook) SetDefaultPath(defaultPath string) {
hook.defaultPath = defaultPath
hook.hasDefaultPath = true
}

// Open the file, write to the file, close the file.
// Whichever user is running the function needs write permissions to the file or directory if the file does not yet exist.
func (hook *lfsHook) Fire(entry *logrus.Entry) error {
if hook.writer != nil {
// SetDefaultWriter sets default writer for levels that don't have any defined writer.
func (hook *LfsHook) SetDefaultWriter(defaultWriter io.Writer) {
hook.defaultWriter = defaultWriter
hook.hasDefaultWriter = true
}

// Fire writes the log file to defined path or using the defined writer.
// User who run this function needs write permissions to the file or directory if the file does not yet exist.
func (hook *LfsHook) Fire(entry *logrus.Entry) error {
if hook.writers != nil || hook.hasDefaultWriter {
return hook.ioWrite(entry)
} else {
} else if hook.paths != nil || hook.hasDefaultPath {
return hook.fileWrite(entry)
}

return nil
}

// Write a log line to an io.Writer
func (hook *lfsHook) ioWrite(entry *logrus.Entry) error {
// Write a log line to an io.Writer.
func (hook *LfsHook) ioWrite(entry *logrus.Entry) error {
var (
msg []byte
err error
ok bool
writer io.Writer
msg []byte
err error
ok bool
)

hook.lock.Lock()
defer hook.lock.Unlock()

if _, ok = hook.writer[entry.Level]; !ok {
err = fmt.Errorf("no writer provided for loglevel: %d", entry.Level)
log.Println(err.Error())
return err
if writer, ok = hook.writers[entry.Level]; !ok {
if hook.hasDefaultWriter {
writer = hook.defaultWriter
} else {
return nil
}
}

// use our formatter instead of entry.String()
Expand All @@ -111,12 +140,12 @@ func (hook *lfsHook) ioWrite(entry *logrus.Entry) error {
log.Println("failed to generate string for entry:", err)
return err
}
_, err = hook.writer[entry.Level].Write(msg)
_, err = writer.Write(msg)
return err
}

// Write a log line directly to a file
func (hook *lfsHook) fileWrite(entry *logrus.Entry) error {
// Write a log line directly to a file.
func (hook *LfsHook) fileWrite(entry *logrus.Entry) error {
var (
fd *os.File
path string
Expand All @@ -129,10 +158,16 @@ func (hook *lfsHook) fileWrite(entry *logrus.Entry) error {
defer hook.lock.Unlock()

if path, ok = hook.paths[entry.Level]; !ok {
err = fmt.Errorf("no file provided for loglevel: %d", entry.Level)
log.Println(err.Error())
return err
if hook.hasDefaultPath {
path = hook.defaultPath
} else {
return nil
}
}

dir := filepath.Dir(path)
os.MkdirAll(dir, os.ModePerm)

fd, err = os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666)
if err != nil {
log.Println("failed to open logfile:", path, err)
Expand All @@ -151,7 +186,7 @@ func (hook *lfsHook) fileWrite(entry *logrus.Entry) error {
return nil
}

// Return configured log levels
func (hook *lfsHook) Levels() []logrus.Level {
return hook.levels
// Levels returns configured log levels.
func (hook *LfsHook) Levels() []logrus.Level {
return logrus.AllLevels
}

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