tail

README

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.

Installing

go get github.com/ActiveState/tail

Building

To build and test the package,

make test

To build the toy command-line program gotail,

cd cmd/gotail
make
./gotail -h

TODO

• Support arbitrary values for Location

Documentation

Index

• Variables
• type Config
• type Line
• type Tail
  • func TailFile(filename string, config Config) (*Tail, error)
  • func (tail *Tail) Stop() error

Variables

var (
	ErrStop = fmt.Errorf("tail should now stop")
)

Types

type Config

type Config struct {
	Location    int  // Tail from last N lines (tail -n)
	Follow      bool // Continue looking for new lines (tail -f)
	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
	MaxLineSize int  // If non-zero, split longer lines into multiple lines
}

Tail configuration

type Line

type Line struct {
	Text string
	Time time.Time
}

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 with the specified configuration. Output stream is made available via the `Tail.Lines` channel. To handle errors during tailing, invoke the `Wait` method after finishing reading from the `Lines` channel.

func (*Tail) Stop

func (tail *Tail) Stop() error

Stop stops the tailing activity.