add basic docker build and push workflow and comment dockerfile

Author: jessebot

.github/workflows/docker-push-daily.yml

@@ -0,0 +1,81 @@
+name: nightly and on.push docker builds
+
+on:
+  # to trigger manually if we really need it
+  workflow_dispatch:
+    inputs:
+      tag_name:
+        description: "the name of the tag for the docker image"
+        type: "string"
+        required: true
+
+  # to trigger
+  push:
+    paths:
+      - Dockerfile
+
+  schedule:
+    # * is a special character in YAML so you have to quote this string
+    # triggers every day at 00:00 UTC (midnight)
+    - cron:  '0 0 * * *'
+
+jobs:
+  docker-amd64:
+    environment: 'docker'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        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@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Docker Build and Push
+        if: ${{ github.event == 'workflow_dispatch' }}
+        uses: docker/build-push-action@v5
+        with:
+          push: true
+          # build from the ./docker directory in this repo
+          context: docker
+          platforms: |
+            linux/amd64
+          tags: |
+            jessebot/nextcloud:${{ inputs.tag_name }}
+
+      # push with ref_name if
+      - name: Docker Build and Push
+        if: ${{ github.event != 'workflow_dispatch' && github.event != 'schedule' }}
+        uses: docker/build-push-action@v5
+        with:
+          push: true
+          # build from the ./docker directory in this repo
+          context: docker
+          platforms: |
+            linux/amd64
+          tags: |
+            jessebot/nextcloud:${{ github.ref_name }}
+
+      - name: Get most recent tag
+        if: ${{ github.event == 'schedule' }}
+        run: echo "last_tag=$(git describe --tags --abbrev=0) >> $GITHUB_ENV
+
+      - name: Docker Build and Push
+        if: ${{ github.event == 'schedule' }}
+        uses: docker/build-push-action@v5
+        with:
+          push: true
+          # build from the ./docker directory in this repo
+          context: docker
+          platforms: |
+            linux/amd64
+          tags: |
+            jessebot/nextcloud:nightly
+            jessebot/nextcloud:${{ env.last_tag }}

Dockerfile

@@ -1,2 +1,3 @@
 FROM nextcloud:29.0.1-fpm-alpine
+# add ffmpeg for video preview generation
 RUN apk add --no-cache ffmpeg