fixed graceful shutdown handling

CHANGELOG.md

@@ -78,6 +78,8 @@
 - Trigger the `app.OnTerminate()` hook on `app.Restart()` call.
   _A new bool `IsRestart` field was also added to the `core.TerminateEvent` event._
 
+- Fixed the graceful shutdown handling.
+
 
 ## v0.20.0-rc3
 

apis/serve.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"path/filepath"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/fatih/color"
@@ -189,14 +190,37 @@ func Serve(app core.App, config ServeConfig) (*http.Server, error) {
 		regular.Printf("└─ Admin UI: %s\n", color.CyanString("%s://%s/_/", schema, addr))
 	}
 
+	// WaitGroup to block until server.ShutDown() returns because Serve and similar methods exit immediately.
+	// Note that the WaitGroup would not do anything if the app.OnTerminate() hook isn't triggered.
+	var wg sync.WaitGroup
+
 	// try to gracefully shutdown the server on app termination
 	app.OnTerminate().Add(func(e *core.TerminateEvent) error {
 		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 		defer cancel()
+
+		wg.Add(1)
 		server.Shutdown(ctx)
+		if e.IsRestart {
+			// wait for execve up to 3 seconds before exit
+			time.AfterFunc(3*time.Second, func() {
+				wg.Done()
+			})
+		} else {
+			wg.Done()
+		}
+
 		return nil
 	})
 
+	// wait for the graceful shutdown to complete before exit
+	defer wg.Wait()
+
+	// ---
+	// @todo consider removing the server return value because it is
+	// not really useful when combined with the blocking serve calls
+	// ---
+
 	// start HTTPS server
 	if config.HttpsAddr != "" {
 		// if httpAddr is set, start an HTTP server to redirect the traffic to the HTTPS version

core/base.go

@@ -553,20 +553,15 @@ func (app *BaseApp) Restart() error {
 		return err
 	}
 
-	// restart the app bootstrap as a fallback in case the
+	return app.OnTerminate().Trigger(&TerminateEvent{
-	// terminate event or execve fails for some reason
-	defer app.Bootstrap()
-
-	// optimistically trigger the terminate event
-	terminateErr := app.OnTerminate().Trigger(&TerminateEvent{
 		App:       app,
 		IsRestart: true,
-	})
+	}, func(e *TerminateEvent) error {
-	if terminateErr != nil {
+		// attempt to restart the bootstrap process in case execve returns an error for some reason
-		return terminateErr
+		defer app.Bootstrap()
-	}
 
-	return syscall.Exec(execPath, os.Args, os.Environ())
+		return syscall.Exec(execPath, os.Args, os.Environ())
+	})
 }
 
 // RefreshSettings reinitializes and reloads the stored application settings.

examples/base/main.go

@@ -110,7 +110,7 @@ func main() {
 	// GitHub selfupdate
 	ghupdate.MustRegister(app, app.RootCmd, ghupdate.Config{})
 
-	app.OnAfterBootstrap().Add(func(e *core.BootstrapEvent) error {
+	app.OnAfterBootstrap().PreAdd(func(e *core.BootstrapEvent) error {
 		app.Dao().ModelQueryTimeout = time.Duration(queryTimeout) * time.Second
 		return nil
 	})

pocketbase.go

@@ -152,12 +152,13 @@ func (pb *PocketBase) Execute() error {
 		sigch := make(chan os.Signal, 1)
 		signal.Notify(sigch, os.Interrupt, syscall.SIGTERM)
 		<-sigch
+
 		done <- true
 	}()
 
 	// execute the root command
 	go func() {
-		// leave to the commands to decide whether to print their error or not
+		// note: leave to the commands to decide whether to print their error
 		pb.RootCmd.Execute()
 
 		done <- true