Stop dispatcher can be used to manage Golang application gracefull shutdown. It allow you to register application shutdown callback (to close some database connection, clean temp folder ...) You can event use it in sub process to manage when operation end up normally or when it failed.
go get -u github.com/gol4ng/stop-dispatcher
A job application (will perfom a task then end)
package main
import (
"context"
"fmt"
"log"
stop_dispatcher "github.com/gol4ng/stop-dispatcher"
"github.com/gol4ng/stop-dispatcher/reason_handler"
"github.com/gol4ng/stop-dispatcher/stop_emitter"
)
func main() {
// root context
ctx := context.Background()
// stop dispatcher with log reason handler
stopDispatcher := stop_dispatcher.NewDispatcher(
stop_dispatcher.WithReasonHandler(reason_handler.Log()),
stop_dispatcher.WithEmitter(
// Listen SIGINT, SIGTERM
stop_emitter.DefaultKillerSignalEmitter(),
),
)
// Register a killer signal emitter
stopDispatcher.RegisterEmitter(
func(stop func(reason stop_dispatcher.Reason)) {
// Start the job
for i := 0; i < 10; i++ {
fmt.Printf("%d time elapsed\n", i)
}
// The process is finish so it trigger application stopping
stop("process finished")
},
)
// Register all your stopping callback
stopDispatcher.RegisterCallback(
stop_dispatcher.CallbackFunc(func(ctx context.Context) error {
// Do all your cleannup action here
log.Println("Closing database connection")
log.Println("Clean temp file")
return nil
}),
)
// Wait will block until stopping reason was received
if err := stopDispatcher.Wait(ctx); err != nil {
log.Printf("error occured during stopping application : %s", err)
}
log.Println("Application stopped")
}A runner application (like http server)
package main
import (
"context"
"fmt"
"log"
"net"
"net/http"
"strconv"
"sync/atomic"
stop_dispatcher "github.com/gol4ng/stop-dispatcher"
"github.com/gol4ng/stop-dispatcher/reason_handler"
"github.com/gol4ng/stop-dispatcher/stop_emitter"
)
func main() {
// root context
ctx := context.Background()
// stop dispatcher with log reason handler
stopDispatcher := stop_dispatcher.NewDispatcher(
stop_dispatcher.WithReasonHandler(reason_handler.Log()),
stop_dispatcher.WithEmitter(
// Listen SIGINT, SIGTERM
stop_emitter.DefaultKillerSignalEmitter(),
),
)
i := int64(0)
httpServer := &http.Server{
Handler: http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
writer.Write([]byte(strconv.Itoa(int(atomic.LoadInt64(&i)))))
atomic.AddInt64(&i, 1)
}),
BaseContext: func(_ net.Listener) context.Context {
return ctx
},
}
// Register a killer signal emitter
stopDispatcher.RegisterEmitter(
// Start the httpServer and listen when it stop
func(stop func(reason stop_dispatcher.Reason)) {
if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
stop(fmt.Errorf("http server[%s] : %w", httpServer.Addr, err))
}
},
)
// Register all your stopping callback
stopDispatcher.RegisterCallbacks(
stop_dispatcher.CallbackFunc(func(ctx context.Context) error {
return httpServer.Shutdown(ctx)
}),
stop_dispatcher.CallbackFunc(func(ctx context.Context) error {
log.Println("Closing all database connection")
return nil
}),
)
// Wait will block until stopping reason was received
if err := stopDispatcher.Wait(ctx); err != nil {
log.Printf("error occured during stopping application : %s", err)
}
log.Println("Application stopped")
}