Sending GitHub events to an application

Prerequisites

Before you begin, set up your account and install the command line environment. While you can use the console to create your application, this example uses the CLI.

• Ensure that you have a Pay-as-you-Go account.
• Set up your Code Engine CLI environment.
• Create and work with a project.

All Code Engine users are required to have a Pay-as-you-Go account. Tutorials might incur costs. Use the Cost Estimator to generate a cost estimate based on your projected usage. For more information, see Code Engine pricing.

Create an application

Create an application to receive your GitHub events called my-github-app that uses an image called github with the ibmcloud ce app create command. This app logs each commit event that occurs in the GitHub repository. The image is built from github.go, available from the Samples for IBM Cloud Code Engine GitHub repo.

ibmcloud ce application create --name my-github-app --image icr.io/codeengine/github --min-scale 1

After your application creates, verify that your application is in a Ready state and find the application URL.

ibmcloud ce application get --name my-github-app

The application URL is found in the URL field in the example output.

Name:               my-github-app  
ID:                 abcdefgh-abcd-abcd-abcd-1a2b3c4d5e6f 
Project Name:       myproject  
Project ID:         01234567-abcd-abcd-abcd-abcdabcd1111  
Age:                20h  
Created:            2022-11-28T13:16:49-06:00  
URL:                https://my-github-app.abcdabcdabc.us-south.codeengine.appdomain.cloud  
Cluster Local URL:  http://my-github-app.abcdabcdabc.svc.cluster.local  
Console URL:        https://cloud.ibm.com/codeengine/project/us-south/abcdefgh-abcd-abcd-abcd-1a2b3c4d5e6f/application/my-github-app/configuration  
Status Summary:     Application deployed successfully
...

Create a webhook

Create a GitHub webhook to subscribe your application to GitHub events. You can subscribe to one or more webhook events. When an event that you subscribe to occurs, GitHub sends a payload to your application. For more information, see Webhook events and payloads.

To create a GitHub webhook, follow these steps.

1. Go to your GitHub repository and select Settings.
2. Select Webhooks -> Add webhook. Note that your GitHub repository might use Hooks instead of Webhooks.
3. Enter your application URL as your Payload URL.
4. Select the Content type that your application requires. If you are using the sample github app, then select application/json as your content type.
5. Optional. Add a secret to your webhook. For more information, see Securing your webhooks.
6. Select to Enable SSL Verification.
7. Select Just the push event to trigger your webhook.
8. Ensure Active is selected. You can disable your webhook without deleting it by removing the checkmark.
9. Click Add webhook.

After you finish, verify that your application is subscribed by checking the log files for the application. For more information about logs, see Viewing logs with the CLI.

ibmcloud ce app logs --name my-github-app

In the example output, look for the port that your app is listening on as well as the type of event.

my-github-app-00001-deployment-abcdabcdabc-1234/user-container:    
2022/12/02 17:07:27 Listening on port 8080  
2022/12/02 17:10:08 Event Type: ping  
2022/12/02 17:10:08 Not a 'push' event so exit

Note that if your applications scales to zero, you might receive a message about no instances of your app running. This app has a minimum scale of 1 so it always has a running instance.

Test your GitHub event

Test your webhook by triggering the event that your application expects. In this case, the application is expecting a change to be committed in the GitHub repository.

1. In your GitHub repository, perform an action that triggers your webhook. For the github app, commit a change to a file in the repository.

2. After a minute or two, find the logs for your application. If your application scaled to zero, you might see a message indicating that your app does not have any running instances. Your application scales up when it receives an event so try again in a few minutes. For more information about logs, see Viewing logs with the CLI.

   ibmcloud ce app logs --name my-github-app
   

   For example, see the following output.

   2022/11/28 19:45:28   
   Event:  {  
     "ref": "refs/heads/main",  
     "before": "0a11d22ebdaacdbb7bf5fdb6c92565c7c00fa97b",  
     "after": "af363efb8568874fe219bc73f3bccd0f4991907f",  
     "repository": {  
     
   ...
   
   "committer": {  
     "name": "GitHub",  
         "email": "noreply@github.com",  
         "username": "web-flow"  
       },  
       "added": [],  
       "removed": [],  
       "modified": [  
         "README.md"  
       ]  
     }  
   }  
   2022/11/28 19:45:28 kersten1 committed "af363efb8568874fe219bc73f3bccd0f4991907f" to "refs/heads/main" branch  
   2022/11/28 19:45:28 ibmcloud ce buildrun submit ...  
   
   

   Your output is dependent on the application that you use and the GitHub repository that contains the webhook.

Your webhook is working! Now your app receives notification whenever you commit a file to your GitHub repository.

This application sets the minimum scale to 1 so that an instance of the app is always running. You can set the scale to 0 by updating the app with the following command. ibmcloud ce app update --name my-github-app --min-scale 0.

Clean up

After you finish this tutorial, you can clean up the resources that you created with the following commands.

1. Delete your application

   ibmcloud ce app delete --name my-github-app
   

   When you delete your app, the associated build files are also deleted.

2. Delete the webhook by opening your GitHub settings -> Webhooks and clicking Delete after the webhook name.

3. Delete the images that the build created from IBM Cloud Container Registry.

   1. Navigate to Registry in the IBM Cloud console.
   2. Find the archive and the image that are associated with your application by searching for your application name.
   3. Select the archive and image and delete.