Revise Docker image build:

.github/workflows/build_and_test_docker_on_pr.yml

@@ -0,0 +1,56 @@
+# Test the Docker image on every pull request.
+#
+# The steps are:
+# 1. Build docker image using cached data.
+# 2. Start the docker container.
+# 3. Check that AiiDA is responsive.
+
+name: build-and-test-image-from-pull-request
+
+on:
+  pull_request:
+    path_ignore:
+      - 'docs/**'
+
+jobs:
+
+  build-and-test:
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+
+    steps:
+      -
+        uses: actions/checkout@v2
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      -
+        name: Cache Docker layers
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+      -
+        name: Build image locally
+        uses: docker/build-push-action@v2
+        with:
+          load: true
+          push: false
+          tags: aiida-core:latest
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache
+      -
+        name: Start and test the container
+        run: |
+          export DOCKERID=`docker run -d aiida-core:latest`
+          docker exec --tty $DOCKERID wait-for-services
+          docker logs $DOCKERID
+          docker exec --tty --user aiida $DOCKERID /bin/bash -l -c 'verdi profile show default'
+          docker exec --tty --user aiida $DOCKERID /bin/bash -l -c 'verdi computer show localhost'
+          docker exec --tty --user aiida $DOCKERID /bin/bash -l -c 'verdi daemon status'

.github/workflows/ci-code.yml

@@ -142,32 +142,3 @@ jobs:
       run: |
         verdi devel check-load-time
         .github/workflows/verdi.sh
-
-  docker:
-    runs-on: ubuntu-latest
-    timeout-minutes: 30
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Install docker
-      run: |
-        sudo apt-get update
-        sudo apt-get install apt-transport-https ca-certificates curl software-properties-common
-        curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
-        sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu  $(lsb_release -cs)  stable"
-        sudo apt-get update
-        sudo apt-get install docker-ce
-
-    - name: Build the aiida-core image
-      run:
-        docker build -t aiida-core .
-
-    - name: Run aiida-core image and test the default aiida profile and localhost computer.
-      run: |
-        export DOCKERID=`docker run -d aiida-core`
-        docker exec --tty $DOCKERID wait-for-services
-        docker logs $DOCKERID
-        docker exec --tty --user aiida $DOCKERID /bin/bash -l -c 'verdi profile show default'
-        docker exec --tty --user aiida $DOCKERID /bin/bash -l -c 'verdi computer show localhost'
-        docker exec --tty --user aiida $DOCKERID /bin/bash -l -c 'verdi daemon status'

.github/workflows/push_image_to_dockerhub.yml

@@ -0,0 +1,51 @@
+# Build the new Docker image on every commit to master/develop branch and on every new tag.
+# No caching is involved for the image build. The new image is then pushed to the Docker Hub.
+
+name: build-and-push-to-dockerhub
+
+on:
+  push:
+    branches:
+      - master
+      - develop
+    tags:
+      - "v[0-9]+.[0-9]+.[0-9]+*"
+
+jobs:
+
+  build-and-push:
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+
+    steps:
+      -
+        uses: actions/checkout@v2
+      -
+        name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: ${{ github.repository }}
+          tags: |
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      -
+        name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_TOKEN }}
+      -
+        name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}