GitHub Actions dev-hosted runners PoC

dev_hosted_runner_poc.yml

name: dev-hoster runner PoC

on:
  workflow_dispatch:

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:

  generate-runs-on-info:
    name: Generate runs-on info
    runs-on:
      group: CI
      labels: [ self-hosted, ubuntu-latest ]
    outputs:
      runner-group: ${{ steps.fetch-runners.outputs.runner_group }}
      runner-labels: ${{ steps.fetch-runners.outputs.runner_labels }}
    steps:
      - name: Fetch runners in 'Devs' group
        id: fetch-runners
        run: |
          BRANCH_NAME=${{ github.ref_name }}
          echo "Branch Name: $BRANCH_NAME"
          
          # GitHub Enterprise: http(s)://HOSTNAME/api/v3/orgs/${{ github.repository_owner }}/actions/runners
          MATCHING_LABEL=$(curl -s -H "Authorization: token ${{ secrets.GH_PAT }}" \
          -H "Accept: application/vnd.github.v3+json" \
          https://api.github.com/orgs/${{ github.repository_owner }}/actions/runners | jq -r --arg branch "$BRANCH_NAME" '[.runners[] | select(.status == "online") | select(.labels[].name == $branch)] | length')
          echo "Matching Label Count: $MATCHING_LABEL"

          if [ "$MATCHING_LABEL" -gt 0 ]; then
            echo "runner_group=Devs" >> $GITHUB_OUTPUT
            echo "runner_labels=['dev-hosted','bare-metal','Xcode-15.2.0','macOS-14.2.1','$BRANCH_NAME']" >> $GITHUB_OUTPUT
          else
            echo "runner_group=Shared" >> $GITHUB_OUTPUT
            echo "runner_labels=['self-hosted','bare-metal','Xcode-15.2.0','macOS-14.2.1']" >> $GITHUB_OUTPUT
          fi

  do-stuff:
    name: Do stuff
    needs: [ generate-runs-on-info ]
    runs-on:
      group: ${{ needs.generate-runs-on-info.outputs.runner-group }}
      labels: ${{ fromJson(needs.generate-runs-on-info.outputs.runner-labels) }}
    timeout-minutes: 10
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      - name: Sleep
        run: |
          sleep 1

Idea based on the controversial https://world.hey.com/dhh/we-re-moving-continuous-integration-back-to-developer-machines-3ac6c611

Pros:

• reduced cost for runners used for CI jobs
• ability to inspect logs directly on the dev's machine
• ...

Cons:

• controversial approach
• frowned upon

https://gist.github.com/dhh/c5051aae633ff91bc4ce30528e4f0b60?permalink_comment_id=5060828#gistcomment-5060828