Quickstart for Go in the App Engine Flexible Environment

This quickstart shows you how to create a small App Engine application that displays a short message.

Before you begin

Before running this sample, take the following steps:

  1. Download and install git.
  2. Download Google Cloud SDK.
  3. Alternatively: You can use Google Cloud Shell, which comes with these prerequisites already installed.

The flexible environment requires that billing is configured for your project. If you have not already configured a billing account, you will be prompted to enable billing later in the quickstart.

This quickstart assumes that you are familiar with the Go programming language and that you have installed Go.

Download the Hello World app

We've created a simple Hello World app for Go so you can quickly get a feel for deploying an app to Google Cloud Platform. Follow these steps from a command line to download Hello World to your local machine.

Download the sample app and navigate into the app directory:

  1. Get the Hello World sample app and its dependencies:

    go get -u -d github.com/GoogleCloudPlatform/golang-samples/appengine_flexible/helloworld

  2. Change to the directory that contains the sample code:

    cd $GOPATH/src/github.com/GoogleCloudPlatform/golang-samples/appengine_flexible/helloworld

Run Hello World on your local machine

To run the Hello World app on your local computer:

  1. Start a local web server:

    go run *.go
  2. In your web browser, enter the following address:

You can see the Hello World message from the sample app displayed in the page.

In your terminal window, press Ctrl+C to exit the web server.

Deploy and run Hello World on App Engine

To deploy your app to the App Engine flexible environment, you need to have a Google Cloud Platform Console project.

Create a project in the Google Cloud Platform Console.

  1. Sign in to your Google account.

    If you don't already have one, sign up for a new account.

  2. In the Cloud Platform Console, go to the Projects page and select or create a new project.

    Go to the Projects page

  3. Enable billing for your project.

    Enable billing

  4. Note the Project ID, since it is used for configuration and deployment.
  5. Initialize the Cloud SDK
  6. gcloud init

Deploy the app to App Engine

  1. Deploy the Hello World Go app. Use the aedeploy tool, which will correctly assemble an app's dependencies in the same way that the go tool does.
    1. Install the aedeploy tool:
      go get google.golang.org/appengine/cmd/aedeploy
    2. Deploy your app by prefixing a gcloud app deploy command with aedeploy.
      aedeploy gcloud app deploy
  2. Visit the following address to see your deployed app:

This time, the page that displays the Hello World message is delivered by a web server running on an App Engine instance.

Congratulations! You've deployed your first Go app to App Engine flexible environment!

Clean up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this quickstart:

  1. Go to the Cloud Platform Console.
  2. Select the project you want to shut down, then click Delete project: this schedules the project for deletion.

What's next

Learn the whole platform

Now that you know what it's like to develop and deploy App Engine apps, you can stretch out and see the rest of Google Cloud Platform. You already have the Google Cloud SDK installed and that gives you the tools to interact with products like Google Cloud SQL, Google Cloud Storage, Google Cloud Datastore, and more. For a guided walkthrough that teaches you how to create an application that uses the entire platform, not just App Engine, check out our quickstart on creating the Bookshelf app.

Learn about the App Engine flexible environment

Here are some topics to help continue your learning about App Engine.

Hello World code review

Hello World is the simplest possible App Engine app, as it contains only one service, has only one version, and all of the code is located within the app's root directory. This section describes each of the app files in detail.


The helloworld.go file registers a handler that listens for requests to /, and responds with the 'Hello world!' message.

package main

import (

func main() {
	http.HandleFunc("/", handle)
	http.HandleFunc("/_ah/health", healthCheckHandler)
	log.Print("Listening on port 8080")
	log.Fatal(http.ListenAndServe(":8080", nil))

func handle(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
	fmt.Fprint(w, "Hello world!")

func healthCheckHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "ok")


The app.yaml file describes an application's deployment configuration:

runtime: go
env: flex
Here, app.yaml specifies the runtime used by the app, and sets env: flex, specifying that the app uses the flexible environment.

  • For more information on how the Go runtime works, see The Go Runtime.

Send feedback about...

App Engine flexible environment for Go