Microsoft Teams Notification from GitHub Actions

I was surprised to find out that there is no official GitHub Actions for integrating with Microsoft Teams, because well, Microsoft owns GitHub now. There are third-party actions in the marketplace, but because some of our jobs run on self-hosted runners, I didn't want to take any chances, so decided to write a quick script that notifies Microsoft Teams on build status, and having used Jenkins Office 365 Connector already to integrate with Teams in the past, I had some basic idea of what I wanted to do.

Started out by adding an incoming webhook to a Teams channel where we can send messages to. This URL will be stored as an encrypted secret in GitHub, since anyone who knows this URL will be able to send messages to the channel.

The next step was to define how the message would look like in Teams, which is done through cards. Microsoft even has a nifty designer. At first I created an adaptive card that's more elaborate than the Jenkins plugin's card, but found out the hard way that Teams connectors don't support it. It supports the Office 365 connector card, which has less features.

The last step was just a matter of getting the build status and calling the webhook with the appropriate content.

A working demo can be found at my github-actions-microsoft-teams repository.

Here are some examples of how the notification looks in Teams:

I didn't have too much time for writing the script, so it isn't as robust or pretty, but for now, it's meeting our needs. It can probably be converted into a composite steps action for easier reuse. It could use some refactoring, and more features can be added, such as identifying which job failed, and parsing through the commit log to figure out who made the commits & merges and report on those as well, etc..

Also, I've been writing more PowerShell lately, and found PoshCode documentation that explains coding styles, such as putting the brace on the same line. As far as I can tell, Microsoft doesn't have an official coding style guide for PowerShell. The PoshCode doesn't seem to have a style for the switch statement though...