Webhooks

Webhooks are URLs that allow triggering actions in a system. Rahti supports webhooks to trigger rebuilds. This means that each BuildConfig is listong to a particular URL that includes a secret (more about that later), and that when this URL is called, a build will be triggered. There few types of formats supported: Generic, GitHub, GitLab and Bitbucket. This means that if the source code of the application is in Gitlab, the Gitlab URL type is the one that should be filled in in Gitlab's side.

First, it is necessary to find the secret, in the BuildConfig (in this case called serveimg-generate) look for the name of the secret reference:

oc get bc/serveimg-generate -o yaml

spec:
  triggers:
  - type: GitHub
    github:
      SecretReference:
        name: webhooksecret

Now the secret webhooksecret should have the WebHookSecretKey field:

oc get Secret webhooksecret -o yaml

which output something like:

apiVersion: v1
kind: Secret
data:
  WebHookSecretKey: dGhpc19pc19hX2JhZF90b2tlbgo=
metadata:
  name: webhooksecret
  namespace: mynamespace     # set this to your project namespace

The WebHookSecretKey is encoded in base64, to decode it:

echo 'dGhpc19pc19hX2JhZF90b2tlbgo=' | base64 -d

When the BuildConfig is configured to be triggered by the webhook, and the corresponding secret exists, the webhook URL can be found by using the command oc describe:

$ oc describe bc/serveimg-generate
Name:                serveimg-generate
.
.
.
Webhook GitHub:
        URL:        https://rahti.csc.fi:8443/apis/build.openshift.io/v1/.../<secret>/github
.
.
.

Finally, go to , go to the repository where the code is, and in Settings > Webhooks, click in "Add webhook".

The GitHub WebHook payload URL is the URL above with <secret> replaced with the base64 decoded string of the value of data.WebHookSecretKey above, and the content type is application/json. Leave the filed Secret empty.