Template for tail.go

tail.go

// Package tail implements behaviour of `tail -n 0 -F path`.
package tail

import (
	"time"
)

var (
	pollDelay   = 200 * time.Millisecond // delay between polling to save CPU
	pollTimeout = time.Second            // how long to wait before returning os.ErrNotExist
)

// Tail is an io.ReadCloser with `tail -n 0 -F path` behaviour.
type Tail struct {
}

// NewTail starts tracking the file using polling.
//
// If file already exists tracking begins from the end of the file.
//
// Supported file types: usual, FIFO and symlink.
func NewTail(file string) *Tail {
	panic("TODO")
}

// Read returns appended data as the file grows, keep trying to open a
// file if it is inaccessible, and continue reading from beginning of the
// file when it will became accessible (e.g. after log rotation).
//
// Returned data is not guaranteed to contain full lines of text.
//
// If Read returns any error except io.EOF, then following Read will
// return either some data or io.EOF.
//
// Read may return 0, nil only if len(p) == 0.
//
// Read will return io.EOF only after Close. Following Read will return
// io.EOF.
//
// Read must not be called from simultaneous goroutines, but Close can be
// called simultaneously with Read or Close.
func (t *Tail) Read(p []byte) (int, error) {
	panic("TODO")
}

// Close stops tracking the file.
func (t *Tail) Close() error {
	panic("TODO")
}