How to get pull request number within GitHub Actions workflow

Question

I want to access the Pull Request number in a Github Actions workflow. I can access the GITHUB_REF environment variable that is available. Although on a Pull Request action it has the value: "refs/pull/125/merge". I need to extract just the "125".

I have found a similar post here that shows how to get the current branch using this variable. Although in this case, what I am parsing is different and I have been unable to isolate the Pull Request number.

I have tried using {GITHUB_REF##*/} which resolves to "merge" I have also tried {GITHUB_REF#*/} which resolves to "pull/125/merge"

I only need the Pull Request number (which in my example is 125)

Answer 1

Although it is already answered, the easiest way I found is using the github context. The following example shows how to set it to an environment variable.

env:
  PR_NUMBER: ${{ github.event.number }}

Answer 2

How about using awk to extract parts of GITHUB_REF instead of bash magick?

From awk manpage:

-F fs

--field-separator fs

Use fs for the input field separator (the value of the FS predefined variable).

As long you remember this, it's trivial to extract only part of variable you need. awk is available on all platforms, so step below will work everywhere:

- run:   echo ::set-env name=PULL_NUMBER::$(echo "$GITHUB_REF" | awk -F / '{print $3}')
  shell: bash