release.yml

name: release
on:
  push:
    tags:
      - "v*.*.*"
jobs:
  goreleaser:
    runs-on: ubuntu-latest
    steps:
      # https://github.com/actions/checkout
      - name: Checkout
        uses: actions/checkout@v6
        with:
          fetch-depth: 0

      # https://github.com/actions/setup-go
      - name: Set up Go
        uses: actions/setup-go@v6
        with:
          go-version-file: "go.mod"

      # https://github.com/goreleaser/goreleaser-action
      - name: Run GoReleaser
        uses: goreleaser/goreleaser-action@v6
        with:
          version: latest
          args: release --clean
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Push semver subtags
        shell: python
        run: |
          #!/usr/bin/env python3
          """
          utility for pushing 1- and 2-element semantic version tags from a semver push
          """
          # https://github.com/actions/toolkit/blob/master/docs/action-versioning.md#recommendations

          import logging
          import os
          import re
          import shlex
          import subprocess
          import sys
          from typing import Final, List

          logging.basicConfig(
              format="%(asctime)s %(levelname)s %(message)s",
              datefmt="%Y-%m-%dT%H:%M:%S%z",
              level=os.environ.get("LOG_LEVEL", "debug").upper(),
          )

          # the following regex was tweaked one on from https://semver.org/
          semver: Final = re.compile(
              r"^"
              r"(?:[vVrR])?"
              r"(?P<major>0|[1-9]\d*)\."
              r"(?P<minor>0|[1-9]\d*)\."
              r"(?P<patch>0|[1-9]\d*)"
              r"(?:-"
              r"(?P<prerelease>(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)"
              r"(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*"
              r"))?"
              r"(?:\+(?P<buildmetadata>[0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?"
              r"$"
          )

          # https://docs.github.com/en/actions/learn-github-actions/variables
          ref_name: Final = os.environ.get("GITHUB_REF_NAME")
          actor: Final = os.environ.get("GITHUB_ACTOR")


          def run(cmd: List[str]) -> int:
              """run the given command (in list format)"""
              logging.info("running command %s", " ".join([shlex.quote(word) for word in cmd]))
              try:
                  result = subprocess.check_call(cmd, shell=False)
              except subprocess.CalledProcessError as e:
                  logging.fatal("failed to run command, error: %s", e)
                  sys.exit(1)
              return result


          def gitconfig():
              """
              set the identity of the git comitter in the global git config
              """
              logging.info("configuring git")
              config = {
                  "user.email": f"{actor}@users.noreply.github.com",
                  "user.name": actor,
              }
              for k, v in config.items():
                  logging.debug("setting git config %s=%s", k, v)
                  run(["git", "config", "--global", k, v])


          def main() -> int:
              """
              entrypoint for direct execution; returns an int for use by sys.exit
              """
              logging.info(
                  "%s starting up as unix user %s and actor %s in %s, with ref: %s",
                  __name__,
                  os.environ.get("USER", "-unknown-"),
                  actor,
                  os.getcwd(),
                  ref_name,
              )
              if not ref_name:
                  logging.fatal("cannot continue without a GITHUB_REF_NAME in the environment")
                  return 1
              if not actor:
                  logging.fatal("GITHUB_ACTOR is required to be set in the environment")
                  return 1

              gitconfig()

              if m := semver.match(ref_name):
                  major, minor = m.group("major"), m.group("minor")
                  for tag in (f"v{major}", f"v{major}.{minor}"):
                      msg = f"[skip ci] Update {tag} tag from {ref_name}"
                      logging.info("commit: %s", msg)
                      run(["git", "tag", "-f", "-a", "-m", msg, tag])
                      run(["git", "push", "-f", "origin", tag])
                  return 0

              return 1


          if __name__ == "__main__":
              sys.exit(main())