ci: publish docker container

Publish sfunnel docker image in ghcr.io

.github/workflows/publish_docker.yaml

@@ -0,0 +1,52 @@
+name: docker-publish-ghcr
+
+on:
+  workflow_dispatch:
+  push:
+  pull_request:
+
+permissions:
+  packages: write
+
+env:
+  PLATFORMS: linux/amd64
+
+jobs:
+  docker_build_and_publish:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: "Checkout sfunnel"
+        uses: actions/checkout@v4
+        with:
+          path: sfunnel
+          fetch-depth: 0
+          fetch-tags: 1
+
+      - name: "Set up Docker buildx"
+        uses: docker/setup-buildx-action@v3
+
+      - name: "Login to GitHub Container Registry (ghcr.io)"
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{github.actor}}
+          password: ${{secrets.GITHUB_TOKEN}}
+
+      - name: "Build and push to ghcr"
+        run: |
+          #Cross-build
+          cd sfunnel
+
+          echo "Fix mess with tags in actions/checkout..."
+          git fetch -f && git fetch -f --tags
+
+          export TAG=$(git describe HEAD | sed 's/-.*$//g' | tr -d "v")
+          EXACT_TAG=$(git describe --exact-match --match "v*" || echo "")
+
+          if [[ "${EXACT_TAG}" != "" ]]; then
+            echo "Cross-building and PUSHING!"
+            docker buildx build --platform ${PLATFORMS} --push -f docker/Dockerfile . --tag ghcr.io/${GITHUB_REPOSITORY}:${TAG}
+          else
+            echo "Cross-building ONLY"
+            docker buildx build --platform ${PLATFORMS} -f docker/Dockerfile .
+          fi