Quickstart for Ruby in the App Engine Flexible Environment

Region ID

The REGION_ID is a code that Google assigns based on the region you select when you create your app. Including REGION_ID.r in App Engine URLs is optional for existing apps and will soon be required for all new apps.

To ensure a smooth transition, we are slowly updating App Engine to use region IDs. If we haven't updated your Google Cloud project yet, you won't see a region ID for your app. Since the ID is optional for existing apps, you don't need to update URLs or make other changes once the region ID is available for your existing apps.

Learn more about region IDs.

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

Before you begin

Before running and deploying this quickstart, install the Cloud SDK and then set up a Cloud project for App Engine:

  1. Download and install Cloud SDK:

    Download the SDK

    Note: If you already have the Cloud SDK installed, update it by running the following command:

    gcloud components update
    
  2. Create a new project:

    gcloud projects create [YOUR_PROJECT_ID] --set-as-default
    

    Replace [YOUR_PROJECT_ID] with a string of characters that uniquely identifies your project. For example, my-project-24.

    Verify the project was created:

    gcloud projects describe [YOUR_PROJECT_ID]
    

    You see project details that might look like the following:

    createTime: year-month-hour
    lifecycleState: ACTIVE
    name: project-name
    parent:
    id: '433637338589'
    type: organization
    projectId: project-name-id
    projectNumber: 499227785679
    
  3. Initialize your App Engine app with your project and choose its region:

    gcloud app create --project=[YOUR_PROJECT_ID]
    

    When prompted, select the region where you want your App Engine application located.

  4. Make sure billing is enabled for your project. A billing account needs to be linked to your project in order for the application to be deployed to App Engine.

    Enable billing

    Your flexible environment deployment will incur costs while it is active. Clean up your project when you are finished to avoid ongoing costs.

  5. Install the following prerequisites:

App Engine locations

App Engine is regional, which means the infrastructure that runs your apps is located in a specific region, and Google manages it so that it is available redundantly across all of the zones within that region.

Meeting your latency, availability, or durability requirements are primary factors for selecting the region where your apps are run. You can generally select the region nearest to your app's users, but you should consider the locations where App Engine is available as well as the locations of the other Google Cloud products and services that your app uses. Using services across multiple locations can affect your app's latency as well as its pricing.

You cannot change an app's region after you set it.

If you already created an App Engine application, you can view its region by doing one of the following:

This quickstart demonstrates a simple Ruby app written with the Sinatra web framework that you can deploy 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 the Google Cloud.

  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

This example uses Bundler to run the Hello World app on your local computer:

  1. If you don't already have the Ruby programming language installed, download and install Ruby.

    Download and Install Ruby

  2. Install Bundler:

    gem install bundler
    
  3. Install dependencies for this project:

    bundle install
    
  4. Start a local web server.

    bundle exec ruby app.rb -p 8080
    
  5. In your web browser, enter:

    http://localhost:8080

The Hello World message from the sample app displays on 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:

  1. Deploy the Hello World app by running the following command from the hello_world directory:

    gcloud app deploy

    Learn about the optional flags.

    Common gcloud command flags

    • Include the --version flag to specify an ID that uniquely identifies that version of your app, otherwise one is generated for you. Example: --version [YOUR_VERSION_ID]
    • Include the --project flag to specify an alternate Cloud project ID to what you initialized as the default in the gcloud tool. Example: --project [YOUR_PROJECT_ID]

    Example:

    gcloud app deploy --version pre-prod-5 --project my-sample-app

    To learn more about deploying your app from the command line, see Testing and Deploying Your App . For a list of all the command flags, see the gcloud app deploy reference.

  2. Launch your browser to view the app at https://PROJECT_ID.REGION_ID.r.appspot.com

    gcloud app browse
    where PROJECT_ID represents your Google Cloud project ID.

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!

If you encountered any errors deploying your application, check the troubleshooting tips.

See the following sections for information about cleaning up as well as links to possible next steps that you can take.

Clean up

To avoid incurring charges, you can delete your Cloud project to stop billing for all the resources used within that project.

  1. In the Cloud Console, go to the Manage resources page.

    Go to the Manage resources page

  2. In the project list, select the project that you want to delete and then click Delete .
  3. In the dialog, type the project ID and then click Shut down to delete the project.

What's next

Learn the whole platform

Now that you know what it's like to develop and deploy App Engine apps, you can explore the rest of Google Cloud. You already have the Cloud SDK installed which gives you the tools to interact with products like Cloud SQL, Cloud Storage, Firestore, and more.

For a guided walkthrough that teaches you how to create an app 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.

app.rb

The Hello World app is a basic one-file Sinatra app:

require "sinatra"

get "/" do
  "Hello world!"
end

app.yaml

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

runtime: ruby
env: flex
entrypoint: bundle exec ruby app.rb

# This sample incurs costs to run on the App Engine flexible environment.
# The settings below are to reduce costs during testing and are not appropriate
# for production use. For more information, see:
# https://cloud.google.com/appengine/docs/flexible/ruby/configuring-your-app-with-app-yaml
manual_scaling:
  instances: 1
resources:
  cpu: 1
  memory_gb: 0.5
  disk_size_gb: 10

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

Gemfile

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

source "https://rubygems.org"

gem "sinatra"