Azure Pipelines to Build and Deploy a Python Web App to Azure App Service

In modern DevOps practices, continuous integration and continuous deployment (CI/CD) play a crucial role in delivering high-quality applications efficiently. Azure Pipelines, a part of Azure DevOps, enables developers to automate the building, testing, and deployment of applications to Azure services, including Azure App Service.

In this blog post, we will walk through setting up an Azure Pipeline to build and deploy a Python web application to Azure App Service.Prerequisites
Before we begin, ensure you have the following:

• An Azure DevOps account (Sign up here)
• An Azure Subscription with an App Service created (Create one here)
• A GitHub or Azure Repos repository with your Python web app code (sample code)
• A Service Connection between Azure DevOps and your Azure subscription

Step 1: Create an Azure App Service
If you haven't already created an Azure App Service, follow these steps:

1. Navigate to the Azure Portal.
2. Click on Create a resource > App Service.
3. Select Runtime Stack as Python (e.g., Python 3.10).
4. Choose a Region and App Service Plan based on your needs.
5. Click Review + Create and then Create.
6. Note the App Service Name, as you will use it in the deployment process.

Step 2: Set Up Azure Pipelines1. Create a New Pipeline

1. Go to your Azure DevOps project.
2. Navigate to Pipelines > New Pipeline.
3. Choose your repository source (GitHub, Azure Repos, etc.).
4. Select Starter pipeline or configure with a YAML file.

2. Define Your azure-pipelines.ymlCreate a YAML file (azure-pipelines.yml) in the root of your repository with the following configuration:

trigger:
  - main  # Adjust this based on your branch

pool:
  vmImage: 'ubuntu-latest'

variables:
  pythonVersion: '3.11'

steps:
- task: UsePythonVersion@0
  inputs:
    versionSpec: '$(pythonVersion)'

- script: |
    python -m venv venv
    source venv/bin/activate
    pip install -r requirements.txt
  displayName: 'Install dependencies'

- task: ArchiveFiles@2
  inputs:
    rootFolderOrFile: '.'
    includeRootFolder: false
    archiveType: 'zip'
    archiveFile: '$(Build.ArtifactStagingDirectory)/app.zip'
    replaceExistingArchive: true

- upload: $(Build.ArtifactStagingDirectory)/app.zip
  artifact: drop

- task: AzureWebApp@1
  inputs:
    azureSubscription: '<Your Azure Service Connection>'
    appName: '<Your App Service Name>'
    package: '$(Build.ArtifactStagingDirectory)/app.zip'

3. Save and Run the Pipeline

1. Commit the azure-pipelines.yml file to your repository.
2. Navigate to Pipelines and run the pipeline.
3. Azure Pipelines will build and deploy the app automatically.

Step 3: Verify the DeploymentOnce the pipeline runs successfully:

1. Go to the Azure Portal.
2. Navigate to your App Service.
3. Click on Browse to open your deployed Python web application.
4. Alternatively, visit https://<your-app-name>.azurewebsites.net in a browser.

Conclusion
With Azure Pipelines, you have successfully automated the build and deployment of your Python web application to Azure App Service. This approach ensures faster and more reliable deployments, enabling you to focus on development rather than manual deployments.
Next steps:

• Add unit tests to your pipeline.
• Integrate with monitoring tools like Application Insights.
• Use staging slots for safe deployments.