discord-bot/.github/workflows/push.yml

name: Build and push container
on:
    push:
        branches:
            - main

jobs:
    build-container:
        runs-on: ubuntu-latest
        steps:
            - name: Checkout latest commit
              uses: actions/checkout@v2
              with:
                  ref: ${{ github.event.pull_request.head.sha }}
            - name: Log into registry
              run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login ghcr.io -u ${{ github.actor }} --password-stdin
            - name: Build and push container image
              run: |
                  REGISTRY="ghcr.io/${{ github.repository_owner }}"
                  NAME="discord-bot"

                  ID="$(echo $REGISTRY/$NAME | tr '[A-Z]' '[a-z]')"
                  REF="$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')"

                  [[ "${{ github.ref }}" == "refs/tags/"* ]] && REF=$(echo $REF | sed -e 's/^v//')

                  [ "$REF" == "main" ] && REF=latest

                  docker build . \
                      --tag "$ID:$REF" \

                  docker push "$ID:$REF"