package tail import ( "fmt" "sync" "github.com/influxdata/tail" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/internal/globpath" "github.com/influxdata/telegraf/plugins/inputs" "github.com/influxdata/telegraf/plugins/parsers" ) type Tail struct { Files []string FromBeginning bool Pipe bool tailers []*tail.Tail parser parsers.Parser wg sync.WaitGroup acc telegraf.Accumulator sync.Mutex } func NewTail() *Tail { return &Tail{ FromBeginning: false, } } const sampleConfig = ` ## files to tail. ## These accept standard unix glob matching rules, but with the addition of ## ** as a "super asterisk". ie: ## "/var/log/**.log" -> recursively find all .log files in /var/log ## "/var/log/*/*.log" -> find all .log files with a parent dir in /var/log ## "/var/log/apache.log" -> just tail the apache log file ## ## See https://github.com/gobwas/glob for more examples ## files = ["/var/mymetrics.out"] ## Read file from beginning. from_beginning = false ## Whether file is a named pipe pipe = false ## Data format to consume. ## Each data format has it's own unique set of configuration options, read ## more about them here: ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md data_format = "influx" ` func (t *Tail) SampleConfig() string { return sampleConfig } func (t *Tail) Description() string { return "Stream a log file, like the tail -f command" } func (t *Tail) Gather(acc telegraf.Accumulator) error { return nil } func (t *Tail) Start(acc telegraf.Accumulator) error { t.Lock() defer t.Unlock() t.acc = acc var seek *tail.SeekInfo if !t.Pipe && !t.FromBeginning { seek = &tail.SeekInfo{ Whence: 2, Offset: 0, } } var errS string // Create a "tailer" for each file for _, filepath := range t.Files { g, err := globpath.Compile(filepath) if err != nil { t.acc.AddError(fmt.Errorf("E! Error Glob %s failed to compile, %s", filepath, err)) } for file, _ := range g.Match() { tailer, err := tail.TailFile(file, tail.Config{ ReOpen: true, Follow: true, Location: seek, MustExist: true, Pipe: t.Pipe, }) if err != nil { errS += err.Error() + " " continue } // create a goroutine for each "tailer" t.wg.Add(1) go t.receiver(tailer) t.tailers = append(t.tailers, tailer) } } if errS != "" { return fmt.Errorf(errS) } return nil } // this is launched as a goroutine to continuously watch a tailed logfile // for changes, parse any incoming msgs, and add to the accumulator. func (t *Tail) receiver(tailer *tail.Tail) { defer t.wg.Done() var m telegraf.Metric var err error var line *tail.Line for line = range tailer.Lines { if line.Err != nil { t.acc.AddError(fmt.Errorf("E! Error tailing file %s, Error: %s\n", tailer.Filename, err)) continue } m, err = t.parser.ParseLine(line.Text) if err == nil { t.acc.AddFields(m.Name(), m.Fields(), m.Tags(), m.Time()) } else { t.acc.AddError(fmt.Errorf("E! Malformed log line in %s: [%s], Error: %s\n", tailer.Filename, line.Text, err)) } } if err := tailer.Err(); err != nil { t.acc.AddError(fmt.Errorf("E! Error tailing file %s, Error: %s\n", tailer.Filename, err)) } } func (t *Tail) Stop() { t.Lock() defer t.Unlock() for _, tailer := range t.tailers { err := tailer.Stop() if err != nil { t.acc.AddError(fmt.Errorf("E! Error stopping tail on file %s\n", tailer.Filename)) } tailer.Cleanup() } t.wg.Wait() } func (t *Tail) SetParser(parser parsers.Parser) { t.parser = parser } func init() { inputs.Add("tail", func() telegraf.Input { return NewTail() }) }