Function Example

example_test.go:184–242

()

}

func Example() {
	app := fx.New(
		// Provide all the constructors we need, which teaches Fx how we'd like to
		// construct the *log.Logger, http.Handler, and *http.ServeMux types.
		// Remember that constructors are called lazily, so this block doesn't do
		// much on its own.
		fx.Provide(
			NewLogger,
			NewHandler,
			NewMux,
		),
		// Since constructors are called lazily, we need some invocations to
		// kick-start our application. In this case, we'll use Register. Since it
		// depends on an http.Handler and *http.ServeMux, calling it requires Fx
		// to build those types using the constructors above. Since we call
		// NewMux, we also register Lifecycle hooks to start and stop an HTTP
		// server.
		fx.Invoke(Register),

		// This is optional. With this, you can control where Fx logs
		// its events. In this case, we're using a NopLogger to keep
		// our test silent. Normally, you'll want to use an
		// fxevent.ZapLogger or an fxevent.ConsoleLogger.
		fx.WithLogger(
			func() fxevent.Logger {
				return fxevent.NopLogger
			},
		),
	)

	// In a typical application, we could just use app.Run() here. Since we
	// don't want this example to run forever, we'll use the more-explicit Start
	// and Stop.
	startCtx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()
	if err := app.Start(startCtx); err != nil {
		log.Fatal(err)
	}

	// Normally, we'd block here with <-app.Done(). Instead, we'll make an HTTP
	// request to demonstrate that our server is running.
	if _, err := http.Get("http://localhost:8080/"); err != nil {
		log.Fatal(err)
	}

	stopCtx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()
	if err := app.Stop(stopCtx); err != nil {
		log.Fatal(err)
	}

	// Output:
	// Executing NewLogger.
	// Executing NewMux.
	// Executing NewHandler.
	// Starting HTTP server.
	// Got a request.
	// Stopping HTTP server.