alice.pds.demo.boltless.dev
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1package logview
2
3import (
4 "bufio"
5 "context"
6 "io"
7 "strings"
8
9 "github.com/hpcloud/tail"
10 "tangled.org/core/spindle/artifactstore"
11 "tangled.org/core/spindle/db"
12 "tangled.org/core/spindle/models"
13)
14
15// streams a workflow's log lines: tails the log file while running, reads
16// the uploaded artifact once finished, same for every role. stop ends a
17// live follow early, the channel closes when the source drains or ctx ends
18func Follow(ctx context.Context, d *db.DB, reader artifactstore.Reader, logDir string, wid models.WorkflowId, finished bool) (<-chan *tail.Line, func(), error) {
19 if finished && reader != nil && d != nil {
20 if fl, err := d.GetFinishedLog(wid.Name); err == nil && fl.Ref != "" {
21 rc, err := reader.Open(ctx, fl.Ref)
22 if err == nil {
23 ch := make(chan *tail.Line, 64)
24 followCtx, cancel := context.WithCancel(ctx)
25 go func() {
26 defer close(ch)
27 defer rc.Close()
28 scanner := bufio.NewScanner(rc)
29 for scanner.Scan() {
30 select {
31 case <-followCtx.Done():
32 return
33 case ch <- &tail.Line{Text: strings.TrimSuffix(scanner.Text(), "\r")}:
34 }
35 }
36 }()
37 return ch, cancel, nil
38 }
39 }
40 }
41
42 t, err := tail.TailFile(models.LogFilePath(logDir, wid), tail.Config{
43 Follow: !finished,
44 ReOpen: !finished,
45 MustExist: false,
46 Location: &tail.SeekInfo{Offset: 0, Whence: io.SeekStart},
47 })
48 if err != nil {
49 return nil, nil, err
50 }
51 return t.Lines, func() { _ = t.Stop() }, nil
52}