Building a CI/CD Pipeline Using GitHub Actions for .NET Applications in Azure

Introduction

In this guide, we will build a Continuous Integration and Continuous Deployment (CI/CD) pipeline from scratch using GitHub Actions. This pipeline will be used to deploy an ASP.NET Core 9 Web API application to Microsoft Azure. Follow the steps below to implement a fully automated deployment process.

Step 1: Setting Up the ASP.NET Core 9 Web API

The application we are deploying is a simple ASP.NET Core 9 Web API with a single GET endpoint. This endpoint returns an object containing the current UTC time and the respective time zone.

Additionally, we will expose an OpenAPI specification using the Swashbuckle UI. Running the application locally and navigating to localhost/swagger will display the API documentation.

Step 2: Creating an Azure App Service

To deploy our application, we need to create an Azure App Service. Follow these steps:

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1. Navigate to the Azure Portal.
2. Go to App Services and create a new Web Application.
3. Choose an existing Resource Group or create a new one.
4. Assign a unique name to the service (e.g., timeservice.azurewebsites.net).

Select Code deployment and choose .NET 9 as the runtime stack.

1. Set the Operating System to Linux for easier deployment.
2. Choose the closest region (e.g., Germany West Central).

Select a pricing tier. The Free Tier (F1) is suitable for demonstrations, but the Basic B1 tier ensures continuous uptime.

• Disable Database options (if not required).
• In Deployment, disable GitHub integration (we will set it up manually).

• Enable Public Access under Networking.
• Disable Application Insights under Monitoring.
• Click Review + Create to finalize the setup.

Step 3: Enabling Basic Publishing Credentials

Since we will use a Publish Profile for deployment:

1. Go to Configuration in the Azure App Service.

Under General Settings, enable SCM_BASIC_AUTH_PUBLISHING_CREDENTIALS.

1. Save the changes.
2. Download the Publish Profile from the Overview tab.

Ensure this file is kept secure, as it contains sensitive credentials.

Step 4: Setting Up GitHub Actions for CI/CD

To define a CI/CD pipeline in GitHub Actions:

1. Inside the GitHub repository, create a .github/workflows folder.
2. Create a YAML file (build-and-deploy.yml).

Define the following workflow:

Workflow Structure

name: Time Service CI/CD

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on:

? push:

??? branches:

????? - main

? workflow_dispatch:

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env:

? AZURE_WEBAPP_NAME: "timeservice"

? DOTNET_VERSION: "9.0"

? PUBLISH_DIR: "timeAPI/publish"

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jobs:

? build-and-test:

??? runs-on: ubuntu-latest

??? steps:

????? - name: Checkout Repository

??????? uses: actions/checkout@v4

?????

????? - name: Setup .NET

??????? uses: actions/setup-dotnet@v3

??????? with:

????????? dotnet-version: ${{ env.DOTNET_VERSION }}

?????

????? - name: Restore Dependencies

??????? run: dotnet restore timeAPI.sln

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????? - name: Build Application

??????? run: dotnet build timeAPI.sln --configuration Release --no-restore

?????

????? - name: Run Tests

??????? run: dotnet test timeAPI.sln --configuration Release --no-restore --no-build

?????

????? - name: Publish Application

??????? run: dotnet publish timeAPI -c Release -o ${{ env.PUBLISH_DIR }} --no-build

?????

????? - name: Upload Artifact

??????? uses: actions/upload-artifact@v4

??????? with:

????????? name: webapp

????????? path: ${{ env.PUBLISH_DIR }}

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? deploy:

??? runs-on: ubuntu-latest

??? needs: build-and-test

??? steps:

????? - name: Download Artifact

??????? uses: actions/download-artifact@v4

??????? with:

????????? name: webapp

????????? path: ${{ env.PUBLISH_DIR }}

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????? - name: Deploy to Azure Web App

??????? uses: azure/webapps-deploy@v2

??????? with:

????????? app-name: ${{ env.AZURE_WEBAPP_NAME }}

????????? publish-profile: ${{ secrets.AZURE_WEBAPP_PUBLISH_PROFILE }}

????????? package: ${{ env.PUBLISH_DIR }}

Step 5: Adding Secrets in GitHub

1. Navigate to your GitHub repository. Go to Settings > Secrets and variables > Actions.
2. Click New repository secret.
3. Name it AZURE_WEBAPP_PUBLISH_PROFILE.
4. Paste the contents of the Publish Profile.

Click Add secret.

Step 6: Running the CI/CD Pipeline

1. Commit and push the workflow file to the repository.
2. Go to Actions in GitHub.
3. Monitor the Build and Test and Deploy jobs.
4. Once deployed, access the API at https://timeservice.azurewebsites.net/swagger.

Conclusion

You have successfully built and deployed an ASP.NET Core 9 Web API to Azure using GitHub Actions. This CI/CD pipeline automates the deployment process, ensuring a seamless integration and delivery workflow.

For further improvements, consider adding:

• Code quality analysis (e.g., SonarQube).
• Automated security checks.
• Database migrations.

To learn more about deploying .NET applications using containers, check out our next guide!

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