How to run a pipeline step only when pushing to a new branch?

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How to run a pipeline step only when pushing to a new branch?

2021-01-07

Categories: DevOps

GitHub sends push hook when pushing to a new branch and merging a PR. How can we distinguish between them?

We are running integration test by triggering a downstream build when a PR is merged into specific branches. In the downstream repository, we pull all the docker images which has been built and pushed from upstream. The thing is we also used the drone-convert-pathschanged to only publish what modules has been changed.

So, what happens when pushing to a new release-* branch? No code changed -> publish steps won’t run -> the docker images does not exist -> integration test failed. How can we solve this situation?

GitHub created two hooks when pushing to a new branch:

X-GitHub-Event: create
X-GitHub-Event: push

Since Drone ignores the “create” event, how can we know that a branch has been created in a “push” event? By looking at the Webhook payloads docs, we can check if “Created” is true or false. Turn out that there is another way to check.

Created: https://github.com/drone/drone/pull/3052

A condition for a step to run when pushing to a new branch will be something like this:

1  when:
2    action:
3    - create
4    branch:
5    - release-*
6    event:
7    - push

It can be distinguished with the step is run when a PR is merged into release-*:

1  when:
2    action:
3      exclude:
4      - create
5    branch:
6    - release-*
7    event:
8    - push

Tags: drone ci monorepo integration-test golang

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