A tiny Go library for deterministic shutdown of goroutines
APACHE-2.0 License
Stager is a library to help write code where you are in control of start and shutdown of concurrent operations. I.e. you know when goroutines start and stop and in which order.
An example is below:
package main
import (
"context"
"log"
"time"
"github.com/ash2k/stager"
)
func main() {
defer log.Print("Exiting main")
st := stager.New()
s := st.NextStage()
s.Go(func(ctx context.Context) error {
log.Print("Start 1.1")
defer log.Print("Stop 1.1")
<-ctx.Done()
return nil
})
s.Go(func(ctx context.Context) error {
log.Print("Start 1.2")
defer log.Print("Stop 1.2")
<-ctx.Done()
return nil
})
s = st.NextStage()
s.Go(func(ctx context.Context) error {
log.Print("Start 2")
defer log.Print("Stop 2")
<-ctx.Done()
return nil
})
s = st.NextStage()
s.Go(func(ctx context.Context) error {
log.Print("Start 3")
defer log.Print("Stop 3")
<-ctx.Done()
return nil
})
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
err := st.Run(ctx)
if err != nil {
log.Fatal(err)
}
}
Output:
2020/12/15 15:34:41 Start 3
2020/12/15 15:34:41 Start 1.2
2020/12/15 15:34:41 Start 1.1
2020/12/15 15:34:41 Start 2
2020/12/15 15:34:46 Stop 3
2020/12/15 15:34:46 Stop 2
2020/12/15 15:34:46 Stop 1.2
2020/12/15 15:34:46 Stop 1.1
2020/12/15 15:34:46 Exiting main
Note the following: