tail

package
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 Go to latest Published: Apr 28, 2015 License: MIT, MIT Imports: 12 Imported by: 0

README

Build Status

Go package for tail-ing files

A Go package striving to emulate the features of the BSD tail program.

t, err := tail.TailFile("/var/log/nginx.log", tail.Config{Follow: true})
for line := range t.Lines {
    fmt.Println(line.Text)
}

See API documentation.

Log rotation

Tail comes with full support for truncation/move detection as it is designed to work with log rotation tools.

Installing

go get github.com/ActiveState/tail/...

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var (
	// DefaultLogger is used when Config.Logger == nil
	DefaultLogger = log.New(os.Stderr, "", log.LstdFlags)
	// DiscardingLogger can be used to disable logging output
	DiscardingLogger = log.New(ioutil.Discard, "", 0)
)
View Source 
var (
	ErrStop = fmt.Errorf("tail should now stop")
)

Functions

func Cleanup 

func Cleanup()

Cleanup removes inotify watches added by the tail package. This function is meant to be invoked from a process's exit handler. Linux kernel may not automatically remove inotify watches after the process exits.

func OpenFile 

func OpenFile(name string) (file *os.File, err error)

Types

type Config 

type Config struct {
	// File-specifc
	Location    *SeekInfo // Seek to this location before tailing
	ReOpen      bool      // Reopen recreated files (tail -F)
	MustExist   bool      // Fail early if the file does not exist
	Poll        bool      // Poll for file changes instead of using inotify
	RateLimiter *ratelimiter.LeakyBucket

	// Generic IO
	Follow      bool // Continue looking for new lines (tail -f)
	MaxLineSize int  // If non-zero, split longer lines into multiple lines

	// Logger, when nil, is set to tail.DefaultLogger
	// To disable logging: set field to tail.DiscardingLogger
	Logger *log.Logger
}

Config is used to specify how a file must be tailed.

type Line 

type Line struct {
	Text string
	Time time.Time
	Err  error // Error from tail
}

func NewLine 

func NewLine(text string) *Line

NewLine returns a Line with present time.

type SeekInfo 

type SeekInfo struct {
	Offset int64
	Whence int // os.SEEK_*
}

SeekInfo represents arguments to `os.Seek`

type Tail 

type Tail struct {
	Filename string
	Lines    chan *Line
	Config

	tomb.Tomb // provides: Done, Kill, Dying
	// contains filtered or unexported fields
}

func TailFile 

func TailFile(filename string, config Config) (*Tail, error)

TailFile begins tailing the file. Output stream is made available via the `Tail.Lines` channel. To handle errors during tailing, invoke the `Wait` or `Err` method after finishing reading from the `Lines` channel.

func (*Tail) Stop 

func (tail *Tail) Stop() error

Stop stops the tailing activity.

func (*Tail) Tell 

func (tail *Tail) Tell() (offset int64, err error)

Return the file's current position, like stdio's ftell(). But this value is not very accurate. it may readed one line in the chan(tail.Lines), so it may lost one line.

Source Files

View all Source files

Directories

Path Synopsis
cmd
gotail command
Package ratelimiter implements the Leaky Bucket ratelimiting algorithm with memcached and in-memory backends.
 Package ratelimiter implements the Leaky Bucket ratelimiting algorithm with memcached and in-memory backends.

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