Wednesday, March 25, 2020

Implementing CI/CD DevOps pipelines using a simple ASP.NET Core 3.1 MVC application using GitHub Actions and Azure App Services


In this post I will show you how easy it is to implement a CI/CD DevOps pipeline using GitHb Actions. The sample web application I will use is an ASP.NET Core 3.1 MVC application and I will deploy it to Azure App Services. 

Before proceeding, It is assumed that you have the following pre-requisites:
- You already have an Azure Account
- You already have a GitHub account
- You have .NET Core 3.1 (or later) installed on your computer
Creating a simple ASP.NET Core 3.1 application
In a working directory, execute the following command from within a terminal window:

dotnet new mvc -o GithubActions2Azure

Change directory to the newly created app:

cd GithubActions2Azure

Add a .gitignore file to the application:

dotnet new gitignore

Let us make the application our own by, perhaps, changing the title of the app and the background color.

1) Add the following CSS to wwwroot/css/site.css
2) In Views/Home/Index.cshtml, change the main heading from:

<h1 class="display-4">Welcome</h1>

           TO

<h1 class="display-4">Welcome to our MVC Core 3.1 App</h1>

Let us now run the application and see what it looks like. In the terminal window run the following command:

dotnet run

Point your browser to https://localhost:5001. You will see a strangely colored web page that looks like this:


Stop the server by hitting CTRL + C in the terminal window.

Push code to GitHub

We are now ready to push this application to GitGub. Go to GitHub and create a repository. I created a repository named GithubActions2Azure. Copy the commands that are shown on the GitHub page that looks like this:

Back in your application’s terminal window, type the following commands to initialize a git repo, add files to the repo and commit the changes:

git init
git add .
git commit -m "1st commit"

Next, we will push the code to GitHub. Paste the git commands that you copied from GitHub. This is what it looked like for me:

git remote add origin https://github.com/medhatelmasry/GithubActions2Azure.git
git push -u origin master

If you refresh the GitHub page, you will see that the code is in GitHub. It looks like this:

























Azure

The next step is to create a web app in Azure. Login to the Azure portal at https://portal.azure.com/. Click on Create a resource:

Enter “web" in the filter then choose "Web App”:


On the next page, click on the blue Create button:

 

Choose a subscription then create a new Resource Group:


In named my new resource group GithubActions2Azure. Here are all the choices I made:


Click on Create on the next page:


Creation of a new Azure web service takes less than three minutes. When it is completed, a message appears declaring that “Your deployment is complete”. Click on the blue “Go to resource” button:


We need the publish profile. Click on “Get publish profile” to download your publish profile XML file:


Build & Deploy using GitHub Actions
 Back it GitHub, click on the Settings tab of your application’s repo:


Click on Secrets on the left-side:


Click on “Add a new secret”:


Give the secret the name AZURE_WEBAPP_PUBLISH_PROFILE and paste the contents of the publish profile file that you earlier downloaded from the Azure portal for your web app:

 
Click on Actions on the top navigation bar in GitHub:


You will see a multitude of templates for a multitude of technologies and programming languages. We will paste our own template, therefore, click on the “Set up a workflow yourself” link on the right-side:


This will create a .github/Workflows folder in your application. Name the file deploy_to_azure.yml then click on the green “Start commit” button:


Enter a comment and description for the commit then click on the “Commit new file” button:


Go to this site to get an appropriate template for our web app: https://github.com/Azure/webapps-deploy. Scroll down until you find this section then click on dotnet.yml:


Copy the contents of the asp.net-core-webapp-on-azure.yml. Return to the GitHub repo of our application, edit the deploy_to_azure.yml file, and replace the contents by pasting the clipboard. This is what it looks like for me:


On line 18, set the value of AZURE_WEBAPP_NAME to the name of your app. In my case it is GithubActions2Azure.

On line 20, set the value of DOTNET_VERSION with the exact version of .NET Core with which you created your app. You can find out by running the following command in a terminal window:

dotnet --version

In my case, the .NET Core version is 3.1.200.

Click on the green “Start commit” button, give it a title then click on “Commit changes”.

Click on Actions on the top navigation bar:


Click on “Deploy ASP.NET Are all to ..”. If all goes well, there should be a green check mark beside the workflow, which was responsible for building and deploying the app to Azure. Click on “Updated deploy_to_azure.yml”.


Click on “build-and-deploy” on the left-side:


You will be comforted by the fact that all tasks completed successfully:


To make sure all is well, go to the Azure portal and click on the URL of your website:


Our ugly looking tomato-colored website appears:


Note that if you make any changes to your source code and push it to GitHub, it will automatically get deployed to Azure. This is what CI/CD is all about. Let's try that.

CI/CD
In a terminal window at your project folder, do a pull in order to get all the changes we made in GitHub when we added the .yml file:

git pull

In wwwroot/css/site.css, change the background-color to wheat. Let us push our changes to Github with these commands:

git add .
git commit -m "changed background color to wheat"
git push origin master

Back in GitHub, you will find that the deployment is running:


Upon completion it will display a green check mark:

Refresh the website in your browser and you will find that it has changed background color to something nicer:


Thanks for coming this far in my tutorial and I hope you found it useful.

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