-
Notifications
You must be signed in to change notification settings - Fork 9
/
reloader.go
55 lines (47 loc) · 937 Bytes
/
reloader.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
package ioutil
import (
"bytes"
"embed"
iofs "io/fs"
"os"
)
const (
TriggerFile = "trigger"
)
type Reloader struct {
dir string
fs embed.FS
trigger []byte
loaded bool
loadFn func(fsys iofs.FS)
}
func NewReloader(dir string, fs embed.FS, loadFn func(fsys iofs.FS)) *Reloader {
return &Reloader{
dir: dir,
fs: fs,
trigger: nil,
loaded: false,
loadFn: loadFn,
}
}
func (r *Reloader) FS() iofs.FS {
if fi, err := os.Stat(r.dir); os.IsNotExist(err) || !fi.IsDir() {
return r.fs
}
return os.DirFS(r.dir)
}
func (r *Reloader) needsReload(fsys iofs.FS) bool {
if data, err := iofs.ReadFile(fsys, TriggerFile); err == nil {
yes := bytes.Compare(r.trigger, data) != 0
r.trigger = data
return yes || !r.loaded // ensure loads at least first time
}
return !r.loaded
}
func (r *Reloader) ReloadIfTriggered() {
fsys := r.FS()
if r.needsReload(fsys) {
r.loadFn(fsys)
r.loaded = true
}
}