-
Notifications
You must be signed in to change notification settings - Fork 0
/
run.go
86 lines (76 loc) · 1.61 KB
/
run.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
package main
import (
"fmt"
"log"
"os"
"os/exec"
"syscall"
"time"
fsn "github.com/fsnotify/fsnotify"
)
func run(c *config) error {
w, err := fsn.NewWatcher()
if err != nil {
return fmt.Errorf("watcher: %w", err)
}
// todo: for a first start, "bind address already in use"
// may indicate that there is other process running; react to that
for verb := "started"; ; {
cmd := exec.Command(c.path, c.args...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
// ^^ todo: wrap Stderr so that the "child: " prefix is shown
err = cmd.Start()
if err != nil {
return err
}
t0 := time.Now()
w.Add(c.path)
log.Printf("child %s, pid: %d", verb, cmd.Process.Pid)
done := make(chan struct{})
go func() {
cmd.Wait()
if time.Since(t0).Seconds() < 2 {
log.Printf("child exited early")
}
close(done)
}()
exited := func() bool {
select {
case <-done:
return true
default:
return false
}
}
select {
case ev, ok := <-w.Events:
if !ok {
return fmt.Errorf("watch: event chan closed")
}
switch {
case ev.Has(fsn.Create) || ev.Has(fsn.Write):
if exited() {
continue
}
goto restart
default:
log.Printf("WARN: watch op %s", ev.Op)
}
case err, ok := <-w.Errors:
if !ok {
return fmt.Errorf("watch: error chan closed")
}
return fmt.Errorf("watch: received error: %w", err)
}
restart:
err = cmd.Process.Signal(os.Signal(syscall.SIGTERM))
if err != nil {
// signal was not supported
cmd.Process.Kill()
}
<-done
verb = "restarted"
time.Sleep(200 * time.Millisecond) // better to wait for freed port
}
}