Quickstart for Ruby on App Engine

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

Before running this sample, take the following steps:

  1. Download and install git.
  2. Download Google Cloud SDK.

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 demonstrates a simple Ruby application written with the Sinatra web framework that can be deployed to App Engine. Although this sample uses Sinatra, you can use other frameworks such as Ruby on Rails.

Download the Hello World app

We've created a simple Hello World app for Ruby 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. Clone the Hello World sample app repository to your local machine:

    git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples

    Alternatively, you can download the sample as a zip file and extract it.

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

    cd ruby-docs-samples/appengine/hello_world

Run Hello World on your local machine

To run the Hello World app on your local computer:

  1. Install dependencies for this project by entering the following command:

    bundle install
  2. Start a local web server:

    bundle exec ruby app.rb -p 8080
  3. 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 app:
    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 Ruby app to App Engine flexible environment!

  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.

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 Hello World app is a very basic one-file Sinatra application:

require "sinatra"

get "/" do
  "Hello world!"


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

runtime: ruby
env: flex
entrypoint: bundle exec ruby app.rb -p $PORT
Here, app.yaml specifies the runtime used by the app, and sets env: flex, specifying that the app uses the flexible environment.


Gemfile is used to specify the application's RubyGem dependencies, and Bundler is used to declare and install dependencies. The Hello World application requires one Ruby gem: the Sinatra web framework:

source "https://rubygems.org"

gem "sinatra"

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App Engine flexible environment for Ruby docs