Deploy a custom container to App Service using GitHub Actions

Article
11/29/2022

GitHub Actions gives you the flexibility to build an automated software development workflow. With the Azure Web Deploy action, you can automate your workflow to deploy custom containers to App Service using GitHub Actions.

A workflow is defined by a YAML (.yml) file in the /.github/workflows/ path in your repository. This definition contains the various steps and parameters that are in the workflow.

For an Azure App Service container workflow, the file has three sections:

Section	Tasks
Authentication	1. Retrieve a service principal or publish profile. 2. Create a GitHub secret.
Build	1. Create the environment. 2. Build the container image.
Deploy	1. Deploy the container image.

Prerequisites

An Azure account with an active subscription. Create an account for free
A GitHub account. If you don't have one, sign up for free. You need to have code in a GitHub repository to deploy to Azure App Service.
A working container registry and Azure App Service app for containers. This example uses Azure Container Registry. Make sure to complete the full deployment to Azure App Service for containers. Unlike regular web apps, web apps for containers don't have a default landing page. Publish the container to have a working example.
- Learn how to create a containerized Node.js application using Docker, push the container image to a registry, and then deploy the image to Azure App Service

Generate deployment credentials

The recommended way to authenticate with Azure App Services for GitHub Actions is with a publish profile. You can also authenticate with a service principal or Open ID Connect but the process requires more steps.

Save your publish profile credential or service principal as a GitHub secret to authenticate with Azure. You'll access the secret within your workflow.

A publish profile is an app-level credential. Set up your publish profile as a GitHub secret.

Go to your app service in the Azure portal.
On the Overview page, select Get Publish profile.

Note

As of October 2020, Linux web apps will need the app setting WEBSITE_WEBDEPLOY_USE_SCM set to true before downloading the file. This requirement will be removed in the future. See Configure an App Service app in the Azure portal, to learn how to configure common web app settings.
Save the downloaded file. You'll use the contents of the file to create a GitHub secret.

You can create a service principal with the az ad sp create-for-rbac command in the Azure CLI. Run this command with Azure Cloud Shell in the Azure portal or by selecting the Try it button.

az ad sp create-for-rbac --name "myApp" --role contributor \
                            --scopes /subscriptions/<subscription-id>/resourceGroups/<group-name>/providers/Microsoft.Web/sites/<app-name> \
                            --json-auth

In the example, replace the placeholders with your subscription ID, resource group name, and app name. The output is a JSON object with the role assignment credentials that provide access to your App Service app. Copy this JSON object for later.

  {
    "clientId": "<GUID>",
    "clientSecret": "<GUID>",
    "subscriptionId": "<GUID>",
    "tenantId": "<GUID>",
    (...)
  }

Important

It is always a good practice to grant minimum access. The scope in the previous example is limited to the specific App Service app and not the entire resource group.

OpenID Connect is an authentication method that uses short-lived tokens. Setting up OpenID Connect with GitHub Actions is more complex process that offers hardened security.

If you don't have an existing application, register a new Active Directory application and service principal that can access resources. Create the Active Directory application.
```
az ad app create --display-name myApp
```
This command will output JSON with an appId that is your client-id. Save the value to use as the AZURE_CLIENT_ID GitHub secret later.

You'll use the objectId value when creating federated credentials with Graph API and reference it as the APPLICATION-OBJECT-ID.
Create a service principal. Replace the $appID with the appId from your JSON output.

This command generates JSON output with a different objectId and will be used in the next step. The new objectId is the assignee-object-id.

Copy the appOwnerTenantId to use as a GitHub secret for AZURE_TENANT_ID later.
```
 az ad sp create --id $appId
```
Create a new role assignment by subscription and object. By default, the role assignment will be tied to your default subscription. Replace $subscriptionId with your subscription ID, $resourceGroupName with your resource group name, and $assigneeObjectId with the generated assignee-object-id. Learn how to manage Azure subscriptions with the Azure CLI.
```
az role assignment create --role contributor --subscription $subscriptionId --assignee-object-id  $assigneeObjectId --assignee-principal-type ServicePrincipal --scopes /subscriptions/$subscriptionId/resourceGroups/$resourceGroupName/providers/Microsoft.Web/sites/
```
Run the following command to create a new federated identity credential for your active directory application.
- Replace APPLICATION-OBJECT-ID with the objectId (generated while creating app) for your Active Directory application.
- Set a value for CREDENTIAL-NAME to reference later.
- Set the subject. The value of this is defined by GitHub depending on your workflow:
  - Jobs in your GitHub Actions environment: repo:< Organization/Repository >:environment:< Name >
  - For Jobs not tied to an environment, include the ref path for branch/tag based on the ref path used for triggering the workflow: repo:< Organization/Repository >:ref:< ref path>. For example, repo:n-username/ node_express:ref:refs/heads/my-branch or repo:n-username/ node_express:ref:refs/tags/my-tag.
  - For workflows triggered by a pull request event: repo:< Organization/Repository >:pull_request.
```
az rest --method POST --uri 'https://graph.microsoft.com/beta/applications/<APPLICATION-OBJECT-ID>/federatedIdentityCredentials' --body '{"name":"<CREDENTIAL-NAME>","issuer":"https://token.actions.githubusercontent.com","subject":"repo:organization/repository:ref:refs/heads/main","description":"Testing","audiences":["api://AzureADTokenExchange"]}' 
```
To learn how to create a Create an active directory application, service principal, and federated credentials in Azure portal, see Connect GitHub and Azure.

Configure the GitHub secret for authentication

In GitHub, browse your repository. Select Settings > Security > Secrets and variables > Actions > New repository secret.

To use app-level credentials, paste the contents of the downloaded publish profile file into the secret's value field. Name the secret AZURE_WEBAPP_PUBLISH_PROFILE.

When you configure your GitHub workflow, you use the AZURE_WEBAPP_PUBLISH_PROFILE in the deploy Azure Web App action. For example:

- uses: azure/webapps-deploy@v2
  with:
    publish-profile: ${{ secrets.AZURE_WEBAPP_PUBLISH_PROFILE }}

In GitHub, browse your repository. Select Settings > Security > Secrets and variables > Actions > New repository secret.

To use user-level credentials, paste the entire JSON output from the Azure CLI command into the secret's value field. Give the secret a name, like AZURE_CREDENTIALS.

When you configure the workflow file later, you use the secret for the input creds of the Azure Login action. For example:

- uses: azure/login@v1
  with:
    creds: ${{ secrets.AZURE_CREDENTIALS }}

You need to provide your application's Client ID, Tenant ID and Subscription ID to the login action. These values can either be provided directly in the workflow or can be stored in GitHub secrets and referenced in your workflow. Saving the values as GitHub secrets is the more secure option.

Open your GitHub repository and go to Settings > Security > Secrets and variables > Actions > New repository secret.
Create secrets for AZURE_CLIENT_ID, AZURE_TENANT_ID, and AZURE_SUBSCRIPTION_ID. Use these values from your Active Directory application for your GitHub secrets. You can find these values in the Azure portal by searching for your active directory application.

GitHub Secret Active Directory Application

AZURE_CLIENT_ID Application (client) ID

AZURE_TENANT_ID Directory (tenant) ID

AZURE_SUBSCRIPTION_ID Subscription ID
Save each secret by selecting Add secret.

GitHub Secret	Active Directory Application
AZURE_CLIENT_ID	Application (client) ID
AZURE_TENANT_ID	Directory (tenant) ID
AZURE_SUBSCRIPTION_ID	Subscription ID

Configure GitHub secrets for your registry

Define secrets to use with the Docker Login action. The example in this document uses Azure Container Registry for the container registry.

Go to your container in the Azure portal or Docker and copy the username and password. You can find the Azure Container Registry username and password in the Azure portal under Settings > Access keys for your registry.
Define a new secret for the registry username named REGISTRY_USERNAME.
Define a new secret for the registry password named REGISTRY_PASSWORD.

Build the Container image

The following example show part of the workflow that builds a Node.js Docker image. Use Docker Login to log into a private container registry. This example uses Azure Container Registry but the same action works for other registries.

name: Linux Container Node Workflow

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2
    - uses: azure/docker-login@v1
      with:
        login-server: mycontainer.azurecr.io
        username: ${{ secrets.REGISTRY_USERNAME }}
        password: ${{ secrets.REGISTRY_PASSWORD }}
    - run: |
        docker build . -t mycontainer.azurecr.io/myapp:${{ github.sha }}
        docker push mycontainer.azurecr.io/myapp:${{ github.sha }}

You can also use Docker sign-in to log into multiple container registries at the same time. This example includes two new GitHub secrets for authentication with docker.io. The example assumes that there's a Dockerfile at the root level of the registry.

name: Linux Container Node Workflow

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2
    - uses: azure/docker-login@v1
      with:
        login-server: mycontainer.azurecr.io
        username: ${{ secrets.REGISTRY_USERNAME }}
        password: ${{ secrets.REGISTRY_PASSWORD }}
    - uses: azure/docker-login@v1
      with:
        login-server: index.docker.io
        username: ${{ secrets.DOCKERIO_USERNAME }}
        password: ${{ secrets.DOCKERIO_PASSWORD }}
    - run: |
        docker build . -t mycontainer.azurecr.io/myapp:${{ github.sha }}
        docker push mycontainer.azurecr.io/myapp:${{ github.sha }}

Deploy to an App Service container

To deploy your image to a custom container in App Service, use the azure/webapps-deploy@v2 action. This action has seven parameters:

Parameter	Explanation
app-name	(Required) Name of the App Service app
publish-profile	(Optional) Applies to Web Apps(Windows and Linux) and Web App Containers(linux). Multi container scenario not supported. Publish profile (*.publishsettings) file contents with Web Deploy secrets
slot-name	(Optional) Enter an existing Slot other than the Production slot
package	(Optional) Applies to Web App only: Path to package or folder. .zip, .war, *.jar or a folder to deploy
images	(Required) Applies to Web App Containers only: Specify the fully qualified container image(s) name. For example, 'myregistry.azurecr.io/nginx:latest' or 'python:3.7.2-alpine/'. For a multi-container app, multiple container image names can be provided (multi-line separated)
configuration-file	(Optional) Applies to Web App Containers only: Path of the Docker-Compose file. Should be a fully qualified path or relative to the default working directory. Required for multi-container apps.
startup-command	(Optional) Enter the start-up command. For ex. dotnet run or dotnet filename.dll

name: Linux Container Node Workflow

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - uses: azure/docker-login@v1
      with:
        login-server: mycontainer.azurecr.io
        username: ${{ secrets.REGISTRY_USERNAME }}
        password: ${{ secrets.REGISTRY_PASSWORD }}

    - run: |
        docker build . -t mycontainer.azurecr.io/myapp:${{ github.sha }}
        docker push mycontainer.azurecr.io/myapp:${{ github.sha }}     

    - uses: azure/webapps-deploy@v2
      with:
        app-name: 'myapp'
        publish-profile: ${{ secrets.AZURE_WEBAPP_PUBLISH_PROFILE }}
        images: 'mycontainer.azurecr.io/myapp:${{ github.sha }}'

on: [push]

name: Linux_Container_Node_Workflow

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    steps:
    # checkout the repo
    - name: 'Checkout GitHub Action' 
      uses: actions/checkout@main
    
    - name: 'Sign in via Azure CLI'
      uses: azure/login@v1
      with:
        creds: ${{ secrets.AZURE_CREDENTIALS }}
    
    - uses: azure/docker-login@v1
      with:
        login-server: mycontainer.azurecr.io
        username: ${{ secrets.REGISTRY_USERNAME }}
        password: ${{ secrets.REGISTRY_PASSWORD }}
    - run: |
        docker build . -t mycontainer.azurecr.io/myapp:${{ github.sha }}
        docker push mycontainer.azurecr.io/myapp:${{ github.sha }}     
      
    - uses: azure/webapps-deploy@v2
      with:
        app-name: 'myapp'
        images: 'mycontainer.azurecr.io/myapp:${{ github.sha }}'
    
    - name: Azure logout
      run: |
        az logout

on: [push]
name: Linux_Container_Node_Workflow

permissions:
      id-token: write
      contents: read

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    steps:
    # checkout the repo
    - name: 'Checkout GitHub Action' 
      uses: actions/checkout@main
    
    - name: 'Sign in via Azure CLI'
      uses: azure/login@v1
      with:
        client-id: ${{ secrets.AZURE_CLIENT_ID }}
        tenant-id: ${{ secrets.AZURE_TENANT_ID }}
        subscription-id: ${{ secrets.AZURE_SUBSCRIPTION_ID }}
    
    - uses: azure/docker-login@v1
      with:
        login-server: mycontainer.azurecr.io
        username: ${{ secrets.REGISTRY_USERNAME }}
        password: ${{ secrets.REGISTRY_PASSWORD }}
    - run: |
        docker build . -t mycontainer.azurecr.io/myapp:${{ github.sha }}
        docker push mycontainer.azurecr.io/myapp:${{ github.sha }}     
      
    - uses: azure/webapps-deploy@v2
      with:
        app-name: 'myapp'
        images: 'mycontainer.azurecr.io/myapp:${{ github.sha }}'
    
    - name: Azure logout
      run: |
        az logout

Next steps

You can find our set of Actions grouped into different repositories on GitHub, each one containing documentation and examples to help you use GitHub for CI/CD and deploy your apps to Azure.

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