From cfa3cd450ba6e3ad6cba5aa6d142501955ab5a19 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ivan=20=C5=A0ari=C4=87?= <ivan@path-variable.com>
Date: Tue, 28 Oct 2025 17:43:54 +0100
Subject: [PATCH] Add GitHub Actions workflow for Docker image build

This workflow builds and publishes a Docker image to Docker Hub upon pushes to the main branch or tags. It includes steps for checking out the repository, setting up QEMU and Docker Buildx, logging into Docker Hub, determining image tags, and building the image.
---
 .github/workflows/docker.yml | 72 ++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 .github/workflows/docker.yml

diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
new file mode 100644
index 0000000..fe925b8
--- /dev/null
+++ b/.github/workflows/docker.yml
@@ -0,0 +1,72 @@
+# Build and publish Docker image to Docker Hub
+# Requires two repository secrets:
+#   DOCKERHUB_USERNAME - your Docker Hub username
+#   DOCKERHUB_TOKEN    - a Docker Hub access token or password
+#
+# Triggers:
+#  - push to main
+#  - push of tags (e.g., v1.2.3)
+#  - manual dispatch
+
+name: Build and Publish Docker image
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - 'v*'
+      - 'release-*'
+  workflow_dispatch:
+
+env:
+  IMAGE_NAME: isaric/mqtt-pub-java
+
+permissions:
+  contents: read
+
+jobs:
+  build-and-push:
+    name: Build and push Docker image
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU (for multi-arch builds)
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Determine image tags
+        id: tag
+        env:
+          IMAGE_NAME: ${{ env.IMAGE_NAME }}
+        run: |
+          SHORT_SHA=${GITHUB_SHA::7}
+          IMAGE="${IMAGE_NAME}"
+          TAGS="${IMAGE}:latest,${IMAGE}:${SHORT_SHA}"
+          if [[ "${GITHUB_REF}" == refs/tags/* ]]; then
+            TAGNAME=${GITHUB_REF#refs/tags/}
+            TAGS="${TAGS},${IMAGE}:${TAGNAME}"
+          fi
+          echo "tags=${TAGS}" >> $GITHUB_OUTPUT
+
+      - name: Build and push image
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          file: ./Dockerfile
+          push: true
+          tags: ${{ steps.tag.outputs.tags }}
+          platforms: linux/amd64,linux/arm64
+          cache-from: type=gha
+          cache-to: type=gha,mode=max