diff --git a/tail.go b/tail.go index d7f9b2b..59f1d2c 100644 --- a/tail.go +++ b/tail.go @@ -2,8 +2,8 @@ package tail import ( "bufio" - "fmt" "io" + "launchpad.net/tomb" "log" "os" "time" @@ -32,8 +32,7 @@ type Tail struct { reader *bufio.Reader watcher FileWatcher - stop chan bool - created chan bool + tomb.Tomb // provides: Done, Kill, Dying } // TailFile channels the lines of a logfile along with timestamp. If @@ -45,15 +44,14 @@ func TailFile(filename string, config Config) (*Tail, error) { panic("only 0/-1 values are supported for Location") } + if config.ReOpen && !config.Follow { + panic("cannot set ReOpen without Follow") + } + t := &Tail{ - filename, - make(chan *Line), - config, - nil, - nil, - nil, - make(chan bool), - make(chan bool)} + Filename: filename, + Lines: make(chan *Line), + Config: config} if t.Poll { log.Println("Warning: not using inotify; will poll ", filename) @@ -75,9 +73,9 @@ func TailFile(filename string, config Config) (*Tail, error) { return t, nil } -func (tail *Tail) Stop() { - tail.stop <- true - tail.close() +func (tail *Tail) Stop() error { + tail.Kill(nil) + return tail.Wait() } func (tail *Tail) close() { @@ -98,11 +96,11 @@ func (tail *Tail) reopen() { if os.IsNotExist(err) { err := tail.watcher.BlockUntilExists() if err != nil { - // TODO: use error channels - log.Fatalf("cannot watch for file creation -- %s", tail.Filename, err) + tail.Killf("failed to detect creation of %s: %s", tail.Filename, err) } continue } + tail.Killf("Unable to open file %s: %s", tail.Filename, err) } break } @@ -125,6 +123,8 @@ func (tail *Tail) readLine() ([]byte, error) { } func (tail *Tail) tailFileSync() { + defer tail.Done() + if !tail.MustExist { tail.reopen() } @@ -136,8 +136,7 @@ func (tail *Tail) tailFileSync() { if tail.Location == 0 { _, err := tail.file.Seek(0, 2) // seek to end of the file if err != nil { - // TODO: don't panic here - panic(fmt.Sprintf("seek error: %s", err)) + tail.Killf("Seek error on %s: %s", tail.Filename, err) } } @@ -152,8 +151,8 @@ func (tail *Tail) tailFileSync() { } } else { if err != io.EOF { - log.Println("Error reading file; skipping this file - ", err) tail.close() + tail.Killf("Error reading %s: %s", tail.Filename, err) return } @@ -170,6 +169,7 @@ func (tail *Tail) tailFileSync() { if !ok { // file got deleted/renamed if tail.ReOpen { + // TODO: no logging in a library log.Printf("File %s has been moved (logrotation?); reopening..", tail.Filename) tail.reopen() log.Printf("File %s has been reopened.", tail.Filename) @@ -182,18 +182,18 @@ func (tail *Tail) tailFileSync() { return } } - case <-tail.stop: - // stop the tailer if requested. + case <-tail.Dying(): // FIXME: respect DRY (see below) + tail.close() return } } } - // stop the tailer if requested. select { - case <-tail.stop: + case <-tail.Dying(): + tail.close() return default: } diff --git a/tail_test.go b/tail_test.go index 278ed27..ba7ced1 100644 --- a/tail_test.go +++ b/tail_test.go @@ -10,8 +10,12 @@ func TestMissingFile(t *testing.T) { if err == nil { t.Error("MustExist:true is violated") } - _, err = TailFile("README.md", Config{Follow: true, MustExist: false}) + _, err = TailFile("/no/such/file", Config{Follow: true, MustExist: false}) if err != nil { t.Error("MustExist:false is violated") } + _, err = TailFile("README.md", Config{Follow: true, MustExist: true}) + if err != nil { + t.Error("MustExist:true on an existing file is violated") + } }