It's easy to get started developing Ruby on Rails apps that run on the Google App Engine flexible environment, and because the apps you create will run on the same infrastructure that powers all of Google's products, you can be confident that they will scale to serve all of your users, whether there are a few or millions of them.
This tutorial assumes you are familiar with Rails web development. It walks you through deploying a new Rail application.
This tutorial requires Ruby 2.3.3 or newer.
Before you begin
Check off each step as you complete it.
Create a project in the Google Cloud Platform Console.
If you haven't already created a project, create one now. Projects enable you to manage all Google Cloud Platform resources for your app, including deployment, access control, billing, and services.
- Open the GCP Console.
- In the drop-down menu at the top, select Create a project.
- Click Show advanced options. Under App Engine location, select a United States location.
- Give your project a name.
- Make a note of the project ID, which might be different from the project name. The project ID is used in commands and in configurations.
Enable billing for your project, and sign up for a free trial.
If you haven't already enabled billing for your project, enable billing now, and sign up for a free trial. Enabling billing allows the application to consume billable resources such as running instances and storing data. During your free trial period, you won't be billed for any services.
Install the Google Cloud SDK.
If you haven't already installed the Google Cloud SDK, install and initialize the Google Cloud SDK now. The SDK contains tools and libraries that enable you to create and manage resources on Google Cloud Platform.
Set up your local environment for Rails
Before you begin, take the following steps:
Alternatively: You can use Google Cloud Shell, which comes with Ruby, Rails, and Cloud SDK already installed.
For additional information on installing Rails and its dependencies, see the official Getting Started with Rails guide.
After you've completed the prerequisites, you can create and deploy a Rails app. The following sections guide you through configuring, running, and deploying an application.
Create a new app
To begin, run the
rails new command to scaffold a new Rails sample
rails new appengine_example
Go to the directory that contains the sample code:
Run the application locally
To run the new Rails application on your local computer:
Install dependencies using Bundler:
Start a local web server:
bundle exec rails server
In your web browser, browse to http://localhost:3000/.
You can see the "Yay! You’re on Rails!" message from the sample app displayed in the page.
Add a simple page
Now add a Welcome page to the generated Rails application. You can
generate the scaffolding for a new page by using
rails generate. The following
command creates a new Rails controller named
WelcomeController with an
bundle exec rails generate controller Welcome index
This command generates the following new directories and files by default
for the new
WelcomeController controller and
Next, open the file
app/views/welcome/index.html.erb, and you should see the
following boilerplate HTML:
<h1>Welcome#index</h1> <p>Find me in app/views/welcome/index.html.erb</p>
Modify the file however you like. For example, you can use the following content:
<h1>Welcome</h1> <p>This is a home page for a new Rails App on Google Cloud Platform!</p>
Finally, you will set the
index controller action as the root action for
Rails, and whenever a user visits the Rails app, they will see your
Next, open the file
config/routes.rb to see the following generated content:
Rails.application.routes.draw do get 'welcome/index' # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html end
Modify this file by adding
Rails.application.routes.draw do get 'welcome/index' # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html root 'welcome#index' end
Save the file and close it. Test the Rails app as you did before and make sure you like what you see.
Deploy the app to the App Engine flexible environment
App Engine flexible environment uses a file called
to describe an application's deployment configuration. If this file is not
gcloud command line tool will try to guess the deployment
configuration. However, it is a good idea to provide this file because Rails
requires a secret key in a
To configure the sample application for deployment to App Engine, create a new
app.yaml at the root of your sample application directory and add
entrypoint: bundle exec rackup --port $PORT env: flex runtime: ruby
Configure Rails secret key
When a Rails app is deployed in the
production environment, the environment
SECRET_KEY_BASE is expected to be set to a secret key that is used to
protect user session data. This environment variable is read in the
First, generate a new secret key:
bundle exec rails secret
Copy the generated secret key to your clipboard. You will use the secret key in the next step.
Next, open the file
app.yaml that you created earlier, and add an
env_variables section. The
env_variables will set environment variables in
production environemnt in App Engine flexible environment. Your
should look like the example below, with
[SECRET_KEY] replaced with the secret
key in your clipboard.
entrypoint: bundle exec rackup --port $PORT env: flex runtime: ruby env_variables: SECRET_KEY_BASE: [SECRET_KEY]
Set up an App Engine flexible environment app
If this is the first time you deploy an app, you will need to create an App Engine flexible environment application. This will help you select the region in which you want to run the Rails app.
Enter this command to create an App Engine app:
gcloud app create
A prompt is displayed with a list of regions. Select a region that supports App Engine flexible environment for Ruby apps.
You can read more about Regions and Zone.
Deploy to App Engine flexible environment
Before you deploy, precompile your Rails assets by running the following command:
RAILS_ENV=production bundle exec rails assets:precompile
After the assets finish compiling, you can proceed to deploy the sample by using the following command:
gcloud app deploy
Wait for the message that notifies you that the update has completed. This can take several minutes.
Access the deployed Rails app
In your web browser, browse to:
or use the command:
gcloud app browse
You will see the following content.
This time, your request is served by the Rails app running in the App Engine flexible environment.
This command deploys the application as described in
app.yaml and sets the
newly deployed version as the default version, causing it to serve all new
traffic. As the app deploys, you might see several repeated messages while the
platform checks whether the app is serving. This is normal. Wait for the
message that notifies you that the update of the app is complete.
If you update your app, you can deploy the updated version by entering the same command you used to deploy the app the first time. The new deployment creates a new version of your app and promotes it to the default version. The older versions of your app will remain, as do their associated VM instances. Be aware that all of these app versions and VM instances are billable resources.
Read App Engine logs
Now that you have deployed your Rails app, you may want to read the logs. You
can read the app logs by using the Logs Viewer
located in the Cloud Console, or by using
gcloud app logs read.
You can learn more about reading logs using the Cloud
Clean up resources
After you've finished the Running Rails 5 in the App Engine tutorial, you can clean up the resources you created on Google Cloud Platform so you won't be billed for them in the future. The following sections describe how to delete or turn off these resources.
The easiest way to eliminate billing is to delete the project you created for the tutorial.
To delete the project:
- In the GCP Console, go to the Projects page.
- In the project list, select the project you want to delete and click Delete project.
- In the dialog, type the project ID, and then click Shut down to delete the project.
Delete an App Engine version
To delete an app version:
- In the GCP Console, go to the App Engine Versions page.
- Click the checkbox next to the non-default app version you want to delete.
- Click the Delete button at the top of the page to delete the app version.
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