Incoming Webhooks

A webhook is a custom callback over HTTP used to setup communication between applications. They provide a way to automatically notify other applications when an event has occurred in your application in the form of an HTTP post payload. This eliminates the need to poll your application to check for new events – the application will alert you when there's something new! Webhooks in FlexDeploy can be used to trigger actions in FlexDeploy based on events happening in other applications, thus eliminating some manual actions. For example, you can setup a webhook to build a project immediately after a push occurs in your SCM. This is just one example, and FlexDeploy's model offers flexibility in what you can accomplish with webhooks.

Incoming Webhook Flow

There are two key aspects to webhooks in FlexDeploy; Providers and Functions. The flow diagram below illustrates how these different pieces interact with each other for a given webhook message:

In the above example we have an inbound webhook message from GitHub for the uri /flexdeploy/webhooks/v1/git/push. 

1. When the message is received in FlexDeploy it will first sequentially evaluate the Provider Match Scripts until a Provider returns true. In the example above:
   1. Evaluate Jira - In this case it returns false.
   2. Evaluate GitHub - In this case it returns true.
   3. Slack is never evaluated because GitHub has a higher priority and returned true.

2. After a Provider has matched, FlexDeploy will find all available Functions for that Provider that match the received URI. In this case the URI was git/push. We can see that of our 6 functions, 2 matched our GitHub provider with the git/push uri. Notice the "Jira - git/push" and "GitHub - stream/create" Functions did not match because both Provider and URI need to match.

The matched Functions will be executed in an indeterminate order. If you need Functions to execute in a specific order then it is recommended to combine the functionality into a single Function script.

Navigation

Webhooks can be accessed from Administration → Integrations → Incoming Webhooks. This page will show all the Webhook Functions configured in FlexDeploy.  Webhook Providers can be accessed from the  button on the functions page. Click  to view the results of any received webhooks, or to resubmit them.

Processing

Webhooks are processed asynchronously. This means that the service will return a 202 Accepted message before attempting to run the functions that you have written. As of 5.5.2, this can be modified. To have a webhook process Synchronously, and return a 200, 404, or 500 depending on what happens while executing it, send in the Header "flex-sync-webhook" with a value of "true". 

If processing synchronously, a 404 is returned if no function matches and is executed. A 200 will be returned if there is no error while processing any matching functions. A 500 will be returned if any function throws an error.

Related Articles

• https://flexagon.com/2020/04/webhooks-part-i-continuous-integration-with-source-control/
• https://flexagon.com/2020/04/webhooks-part-ii-managing-releases-with-issue-tracking/

See more details about each webhook topic below:

• Webhook Providers
• Webhook Functions
• Webhook Messages
• Getting Started with Incoming Webhooks
• Sample Webhook Providers and Functions
• Webhook Security
• Webhook Common Issues and FAQ

• Webhook Context Variables and Methods Reference