lab_3.md

Lab 3 - GitHub Actions

• Create Azure Web App
• Configure GitHub Actions
• Run GitHub Actions
• Continuous Deployment of Changes
• Unit Testing

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Overview

The third lab will deploy a NodeJS Web App using GitHub Actions.

Note: Lab 3 uses the same secret AZURE_CREDENTIALS as in Lab 1

Create Azure Web App

Create the Azure Web App that the pipeline will deploy to. Open Azure Cloud Shell and run the following PowerShell cmdlets:

1. Create the Resource Group rg-lab-3

New-AzResourceGroup -Name 'rg-lab-3' -Location 'eastus2'

2. Create the Azure Web App

New-AzResourceGroupDeployment -ResourceGroupName 'rg-lab-3' -TemplateUri https://raw.githubusercontent.com/softchoice-corp/DevOpsBootcamp/master/lab_3/webapps.deploy.json -Verbose

The ARM template deployment will create a unique name for the Web App and return it on the console under Outputs. Make a note of the uniqueWebAppName value, we will use it later to configure our GitHub Actions pipeline.

Configure GitHub Actions

1. Browse to the workflows-templates/lab_3_webapps.yaml file and copy all of the text.

2. Navigate to Actions and click New Workflow. If prompted to start with a sample workflow click the Set up a workflow yourself button in the top right.

3. Replace all of the sample workflow code in the editor by pasting all the code you copied from workflows-templates/lab_3_webapps.yaml.

4. Modify the AZURE_WEBAPP_NAME variable to use the name of the Web App you created in the previous step.

env:
  AZURE_WEBAPP_NAME: azure-webapp-unique-name
  AZURE_WEBAPP_PACKAGE_PATH: ./lab_3/app

5. GitHub Actions files must be saved in a directory in your repo named .github/workflows/. The directory structure .github/workflows/ should already exist in the path, name your workflow file lab_3_webapps.yaml and click Start Commit.

6. Add a short commit message and click Commit new file.

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Run GitHub Actions

The workflow we just created is triggered by changes made to the files in the lab_3/ directory. Let's make a change here to kick off the workflow. The readme.txt can be modified by simply adding a new line or some text. The act of committing this change to the master branch will instruct GitHub Actions to kick off our workflow.

1. Navigate to Code, and browse to the lab_3/readme.txt file. Click the pencil icon to edit the file, and add a new line. Provide a commit message and commit your change.

2. Navigate to Actions and you should see your Lab_3_WebApp workflow executing.

3. When the Workflow successfully finishes, Open up a browser and go to <Azure Web App name>.azurewebsites.net. Replace <Azure Web App name> with the unique name.

Note: It is possible to find the URL in the Workflow's Deploy to Azure WebApp task's output

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Continuous Deployment of Changes

GitHub provides an action on GitHub marketplace to simplify deployments to Azure Web App application called webapps-deploy. Go to https://github.com/marketplace/actions/azure-webapp for more information.

1. Navigate to Code, open the lab_3/app/public directory and open the index.html file.

2. Find the Octodex image element (img tag) identified with the id attribute octodex.

3. Go to https://octodex.github.com/ and copy the address of an Octodex that you like.

4. Update the alt and src attribute of the octodex img tag with description and copied address, respectively.

5. Enter a commit message and click Commit changes.

6. Navigate to Actions and observe the workflow.

7. When the workflow finishes executing, open your browser and refresh or go to the <Azure Web App name>.azurewebsites.net website to observe the change in the application.

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Unit Testing

We have deployed our application successfully due to the defined unit tests passing successfully. We will now intentionally introduce an error into the application.

1. Navigate to Code, open the lab_3/app/ directory and open the index.js file.

2. Change the Hello, World! text in the service /path response. It can be any misspelling or a completely different text, as long as it is different.

3. Enter a commit message and click Commit changes.

4. Navigate to Actions to observe the Workflow. Which will fail.

5. Click on the Workflow to take a look at the more granular tasks the Workflow is running and expand the npm test task.

6. Notice that the API test unit test failed and the Deploy to Azure WebApp was not skipped. This is the default behaviour.

7. Notice that the test pass message was skipped, but the test fail message task did execute. This is because the test fail message has an if conditional execution on Workflow failure.

- name: test fail message
  if: failure()
  run: |
    echo "npm tests failed! please check your code"

This demonstrates some of the flexibility of GitHub Action Workflows. Go to https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions for more information on other constructs and Workflow syntax.

8. Fix the Workflow by correcting the lab_3/app/index.js file with the proper text and commit the change.

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Clean Up Resources

To mimimize billing usage in your subscription we can remove all of the resources we deployed with GitHub Actions by deleting the Resource Group they are held in. From Azure Cloud Shell run the following command:

az group delete --name rg-lab-3

End of Lab 3

Links to more learning:

• Azure App Service: https://docs.microsoft.com/en-us/azure/app-service/overview
• Node.js in Azure: https://docs.microsoft.com/en-us/azure/app-service/app-service-web-get-started-nodejs
• Unit Testing: https://en.wikipedia.org/wiki/Unit_testing