README
¶
tail 
Package tail implements file tailing with fsnotify.
Fork of nxadm/tail, simplified, reworked and optimized. Currently, supports only Linux and Darwin.
go get github.com/go-faster/tail
package main
import (
"context"
"fmt"
"io"
"os"
"time"
"github.com/go-faster/tail"
)
func main() {
t := tail.File("/var/log/application.txt", tail.Config{
Follow: true, // tail -f
BufferSize: 1024 * 128, // 128 kb for internal reader buffer
// Force polling if zero events are observed for longer than a minute.
// Optional, just a safeguard to be sure that we are not stuck forever
// if we miss inotify event.
NotifyTimeout: time.Minute,
// You can specify position to start tailing, same as Seek arguments.
// For example, you can use the latest processed Line.Location() value.
Location: &tail.Location{Whence: io.SeekStart, Offset: 0},
})
ctx := context.Background()
// Enjoy zero allocation fast tailing with context support.
if err := t.Tail(ctx, func(ctx context.Context, l *tail.Line) error {
_, _ = fmt.Fprintln(os.Stdout, string(l.Data))
return nil
}); err != nil {
panic(err)
}
}
TODO
- Tests for removing, tailing and creating events
- Decide on Windows support
Documentation
¶
Overview ¶
Package tail implements file tailing with fsnotify.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Config ¶
type Config struct {
// Location sets starting file location.
Location *Location
// NotifyTimeout enables additional timeout for file changes waiting.
// Can be used to ensure that we never miss event even if newWatcher fails to
// deliver event.
// Optional.
NotifyTimeout time.Duration
// Follow file after reaching io.EOF, waiting for new lines.
Follow bool
// Initial internal buffer size, optional.
BufferSize int
// Logger to use, optional.
Logger *zap.Logger
// Tracker is optional custom *Tracker.
Tracker Tracker
}
Config is used to specify how a file must be tailed.
type Handler ¶
Handler is called on each log line.
Implementation should not retain Line or Line.Data.
type Line ¶
type Line struct {
Data []byte // do not retain, reused while reading file
Offset int64 // is always the offset from start
}
Line of file.
type Tailer ¶
type Tailer struct {
// contains filtered or unexported fields
}
Tailer implements file tailing.
Use Tail() to start.
func File ¶
File configures and creates new unstarted *Tailer.
Use Tailer.Tail() to start tailing file.
func (*Tailer) Tail ¶
Tail opens file and starts tailing it, reporting observed lines to Handler.
Tail is blocking while calling Handler to reuse internal buffer and reduce allocations. Tail will call Handler in same sequence as lines are observed. See Handler for more info.
Can be called multiple times, but not concurrently.
Source Files