-
Notifications
You must be signed in to change notification settings - Fork 1
/
app.go
85 lines (65 loc) · 1.72 KB
/
app.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
package app
import (
"fmt"
"os"
"os/signal"
"sync"
"syscall"
"github.com/rs/zerolog"
)
// Worker describes something that starts working when Start is called and stops when Close is called.
type Worker interface {
Start()
Close() error
}
// App handles application lifecycle.
type App struct {
log *zerolog.Logger
workers []Worker
}
// NewApp creates and returns new App.
func NewApp(log *zerolog.Logger) *App {
app := &App{
log: log,
workers: []Worker{},
}
return app
}
// Run application, block until interruption received, and handle graceful shutdown.
func (a *App) Run() {
a.log.Info().Msg("app started")
wg := &sync.WaitGroup{}
for _, worker := range a.workers {
wg.Add(1)
a.log.Trace().Func(func(e *zerolog.Event) {
typeOf := fmt.Sprintf("%T", worker)
e.Str("typeOf", typeOf).Msg("starting worker")
})
go worker.Start()
}
a.handleGracefulShutdown(wg)
}
// RegisterWorkers allows to add workers into app lifecycle.
// App will keep them alive until shutdown signal is received.
func (a *App) RegisterWorkers(workers ...Worker) {
a.workers = append(a.workers, workers...)
}
// handleGracefulShutdown listens to sigterm and allows to gracefully shutdown whole app.
func (a *App) handleGracefulShutdown(wg *sync.WaitGroup) {
sigChan := make(chan os.Signal, 1)
signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
<-sigChan
for i := range a.workers {
worker := a.workers[i]
a.log.Trace().Func(func(e *zerolog.Event) {
typeOf := fmt.Sprintf("%T", worker)
e.Str("typeOf", typeOf).Msg("closing worker")
})
wg.Done()
if err := worker.Close(); err != nil {
a.log.Error().Err(err).Msg("error when closing worker")
}
}
wg.Wait()
a.log.Info().Msg("app shutdown gracefully")
}