Using the Ruby platform - AWS App Runner

Using the Ruby platform

The AWS App Runner Ruby platform provides managed runtimes. Each runtime makes it easy to build and run containers with web applications based on a Ruby version. When you use a Ruby runtime, App Runner starts with a managed Ruby runtime image. This image is based on the Amazon Linux Docker image and contains the runtime package for a version of Ruby and some tools. App Runner uses this managed runtime image as a base image, and adds your application code to build a Docker image. It then deploys this image to run your web service in a container.

You specify a runtime for your App Runner service when you create a service using the App Runner console or the CreateService API operation. You can also specify a runtime as part of your source code. Use the runtime keyword in a App Runner configuration file that you include in your code repository. The naming convention of a managed runtime is <language-name><major-version>.

For valid Ruby runtime names and versions, see Ruby runtime release information.

App Runner updates the runtime for your service to the latest version on every deployment or service update. If your application requires a specific version of a managed runtime, you can specify it using the runtime-version keyword in the App Runner configuration file. You can lock to any level of version, including a major or minor version. App Runner only makes lower-level updates to the runtime of your service.

Version syntax for Ruby runtimes: major[.minor[.patch]]

For example: 3.1.2

The following examples demonstrate version locking:

  • 3.1 – Lock the major and minor versions. App Runner updates only patch versions.

  • 3.1.2 – Lock to a specific patch version. App Runner doesn't update your runtime version.

Ruby runtime configuration

When you choose a managed runtime, you must also configure, as a minimum, build and run commands. You configure them while creating or updating your App Runner service. You can do this using one of the following methods:

  • Using the App Runner console – Specify the commands in the Configure build section of the creation process or configuration tab.

  • Using the App Runner API – Call the CreateService or UpdateService API operation. Specify the commands using the BuildCommand and StartCommand members of the CodeConfigurationValues data type.

  • Using a configuration file – Specify one or more build commands in up to three build phases, and a single run command that serves to start your application. There are additional optional configuration settings.

Providing a configuration file is optional. When you create an App Runner service using the console or the API, you specify if App Runner gets your configuration settings directly when it's created or from a configuration file.

Ruby runtime examples

The following examples show App Runner configuration files for building and running a Ruby service.

This example shows a minimal configuration file that you can use with a Ruby managed runtime. For the assumptions that App Runner makes with a minimal configuration file, see Configuration file examples.

Example apprunner.yaml
version: 1.0 runtime: ruby31 build: commands: build: - bundle install run: command: bundle exec rackup --host -p 8080

This example shows the use of all the configuration keys with a Ruby managed runtime.


The runtime version that's used in these examples is 3.1.2. You can replace it with a version you want to use. For latest supported Ruby runtime version, see Ruby runtime release information.

Example apprunner.yaml
version: 1.0 runtime: ruby31 build: commands: pre-build: - scripts/ build: - bundle install post-build: - scripts/ env: - name: MY_VAR_EXAMPLE value: "example" run: runtime-version: 3.1.2 command: bundle exec rackup --host -p 4567 network: port: 4567 env: APP_PORT env: - name: MY_VAR_EXAMPLE value: "example"

These examples shows the source code for a complete Ruby application that you can deploy to a Ruby runtime service.

Example server.rb
# server.rb require 'sinatra' get '/' do 'Hello World!' end
# require './server' run Sinatra::Application
Example Gemfile
# Gemfile source ' (' gem 'sinatra' gem 'puma'
Example apprunner.yaml
version: 1.0 runtime: ruby31 build: commands: build: - bundle install run: command: bundle exec rackup --host -p 4567 network: port: 4567 env: APP_PORT