Generate semver release version in Github actions

This helper Github Action outputs several semantic versioning variables based on the git branch/tag that is building. It assumes that you are using the twgit git flow with conventions of:

• Released tags: vx.x.x
• Upcoming releases: release-x.x.x

(where x.x.x is your release number)

Inputs

• build_number_start: Allows you to bump the Github build number by some predermined value - useful for migrating from another build system and wanting to resume from where you left off (or higher). Not required, defaults to 0

Outputs

• semver_release_string: The full semver release string. e.g. 1.0.0+000598 or 2.1.0-SNAPSHOT4994.
• semver_release_number: Just the release number part, e.g. 1.0.0 or 2.1.0
• semver_is_stable: true or false, whether or not this release is a stable released version or an upcoming snapshot release.
• semver_is_snapshot: true or false, whether or not this release is an upcoming snapshot release or a stable released version.

Usage in a Github actions workflow

# .github/workflows/publish.yml
name: Publish 
# you may wish to trigger this for other specifics, this is an example
on: 
  push:
    tags: 
      - v*
    branches:
      - release-*

jobs:
  publish:
    name: Publish
    runs-on: ubuntu-latest
    steps:
    - id: releasenumber
      uses: pixl8/github-action-twgit-release-version-generator@v1
      with:
        build_number_start: 5609

    # then can use ${{ steps.releasenumber.outputs.variable_name }} in 
    # your step env vars, e.g.
    - name: my-next-step
      env:
        VERSION_NUMBER: ${{ steps.releasenumber.outputs.semver_release_string }}