name	description	languages	products	page_type	urlFragment
Azure Rails Starter	Sample Rails application deployed through Azure Developer CLI (azd) on Azure Container App and Azure Database for PostgreSQL	ruby bicep azdeveloper	azure-container-apps azure-database-postgresql azure-key-vault azure	sample	azure-rails-starter

Deploy a Rails (Ruby) web app with PostgreSQL In Azure Container Apps

This is a starter blueprint for getting your Rails application up and running on Azure using Azure Developer CLI (azd). The Rails application is deployed in an Azure Container App and uses an Azure Postgresql database. The starter uses Infrastructure as Code assets in Bicep to get your application up and running quickly.

The following assets have been provided:

• Infrastructure-as-code (IaC) Bicep files under the infra folder that demonstrate how to provision resources and setup resource tagging for azd.
• A dev container configuration file under the .devcontainer directory that installs infrastructure tooling by default. This can be readily used to create cloud-hosted developer environments such as GitHub Codespaces.
  • Ruby 3.3.0
  • GitHub Copilot
  • Postgresql running in a container (for development)
  • Redis running in a container (for development)
• Continuous deployment workflows for CI providers such as GitHub Actions under the .github directory, and Azure Pipelines under the .azdo directory that work for most use-cases.
• A freshly created Rails 7.1.3 application under directory src.

Getting the Rails app up and running in Azure

Just run azd up to run the end-to-end infrastructure provisioning (azd provision) and deployment (azd deploy) flow. Visit the service endpoint listed to see your application up-and-running!

Quick start:

SECRET_KEY_BASE="$(src/bin/rails secret)" \
RAILS_MASTER_KEY="$(cat src/config/master.key)" \
azd up

Additional Details

The following section examines different concepts that help tie in application and infrastructure.

Application settings

It is recommended to have application settings managed in Azure, separating configuration from code. Typically, the service host allows for application settings to be defined.

• Application settings should be defined on the Bicep resource for the Azure Container App. See main.bicep for an example setting environment variables and using secrets stored in Azure Key Vault.
• Environment variables for your developer environment (Dev Containers or Codespaces) can be defined in .decontainer/Dockerfile.

Managed identities

Managed identities allows you to secure communication between services. This is done without having the need for you to manage any credentials. It is used between Azure Container Apps and Azure Key Vault to automatically retrieve secrets.s

Azure Key Vault

Azure Key Vault allows you to store secrets securely. Your application can access these secrets securely through the use of managed identities.

Getting started with Rails development

Provisioning & deploying with Azure Developer CLI

When changes are made, use azd to validate and apply your changes in Azure, to ensure that they are working as expected:

• Run azd up to validate both infrastructure and application code changes.
• Run azd deploy to validate application code changes only.

Running Rails commands

Move to the src directory:

cd src

Run the Rails server:

bin/rails server

Run the Rails console:

bin/rails console 

Run the Rails migration command:

bin/rails db:migrate

Connecting to the Postgresql database

psql $DATABASE_URL

Re-creating the Rails application

The rails application has been created by running the following command:

rails new --database=postgresql --name=azure-rails-starter src
rm -rf src/.git
cd src
sed -i '' 's/# root.*$/root "home#index"/' config/routes.rb
sed -i '' '/azure_rails_starter_production$/,/DATABASE_PASSWORD/c\
    url: <%= ENV["DATABASE_URL"] %>
' config/database.yml
cat > app/controllers/home_controller.rb <<EOF
class HomeController < ApplicationController
  def index
    render plain: 'Hello World!'
  end
end
EOF

Obtain a shell in the Azure Container App

. ./.env
az containerapp exec --name $SERVICE_RAILS_NAME --resource-group $AZURE_RESOURCE_GROUP_NAME

This can be useful to apply bin/rails db:migrate commands or access the Rails console through bin/rails console. Note that the default bin/docker-entrypoint already runs bin/rails db:prepare.

Clean up resources

    azd down

If you want to make sure you can recreate the same environment, KeyVault needs to be purged:

    azd down --purge

Security consideration

In this repository src/config/master.key has been committed to simplify deployment of the sample application. If you plan on building from the sample app please delete config/master.key and config/credentials.yml.enc. Commit the changes. Then run bin/rails credentials:edit.

Getting help

Sometimes deployment fails because the PostgreSQL resource is still busy and extensions cannot yet be applied. In a case like that just re-run the deployment.

If you're working with this project and running into issues, please post an Issue by clicking on the link above.