.github/workflows/docker.yml: Show Docker images as annotations, show…

… instructions

.github/workflows/docker.yml

@@ -260,9 +260,32 @@ jobs:
         run: |
           .github/workflows/scan-logs.sh "artifacts/$LOGS_ARTIFACT_NAME"
         if: always()
-      - name: List docker images
+      - name: List Docker images
         run: |
-          if [ -f .tox/$TOX_ENV/Dockertags ]; then
-             cat .tox/$TOX_ENV/Dockertags
+          if [ -n "$DOCKER_PUSH_REPOSITORY" -a -f .tox/$TOX_ENV/Dockertags ]; then
+             echo "::notice title=Docker images pushed::$(echo $(cat .tox/$TOX_ENV/Dockertags))"
+             echo
+             echo "To pull an image and enter the container, type:"
+             echo
+             for TAG in $(cat .tox/$TOX_ENV/Dockertags); do
+                 echo "  \$ docker run -it $TAG bash"
+             done
+             echo
+             echo "To use an image as the base for an incremental build, type:"
+             echo
+             TOX_ENV_SANS_INCREMENTAL=${TOX_ENV/-incremental/}
+             DOCKER_IMAGE=${TOX_ENV_SANS_INCREMENTAL#docker-}
+             for TAG in $(cat .tox/$TOX_ENV/Dockertags); do
+                 echo -n "  \$"
+                 if [ "$DOCKER_PUSH_REPOSITORY" != "ghcr.io/sagemath/sage/" ]; then
+                     echo -n " FROM_DOCKER_REPOSITORY=$DOCKER_PUSH_REPOSITORY"
+                 fi
+                 eval DOCKER_TARGET=\${TAG#*$DOCKER_IMAGE-}
+                 DOCKER_TARGET=${DOCKER_TARGET%:*}
+                 if [ "$DOCKER_TARGET" != "with-targets" ]; then
+                     echo -n " FROM_DOCKER_TARGET=$DOCKER_TARGET"
+                 fi
+                 echo " FROM_DOCKER_TAG=${TAG#*:} tox -e $TOX_ENV_SANS_INCREMENTAL-incremental"
+             done
           fi
         if: always()