Merge pull request #5 from macbre/cache-docker-pull

docker pull to use the cache when building

Dockerfile

@@ -1,6 +1,10 @@
 # This file is used by CI pipeline when testing this action
 FROM alpine:latest
 
+RUN apk update \
+  && apk -a info curl \
+  && apk add curl
+
 # these two are passed as build args and stored as env variables
 ARG BUILD_DATE
 ARG GITHUB_SHA

action.yml

@@ -48,15 +48,20 @@ runs:
         # expand commands
         set -x
 
+        docker -v
+
         export BUILD_DATE=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
 
         echo
         echo "Building the Docker image: ${{ inputs.repository }}/${{ inputs.image_name }}:${{ env.COMMIT_TAG }} ..."
         echo
 
-        COMPOSE_DOCKER_CLI_BUILD=1 DOCKER_BUILDKIT=1 \
+        # https://docs.docker.com/develop/develop-images/build_enhancements/
+        # https://docs.docker.com/engine/reference/commandline/build/#specifying-external-cache-sources
+        DOCKER_BUILDKIT=1 \
           docker build . \
           --cache-from ${{ inputs.repository }}/${{ inputs.image_name }}:latest \
+          --build-arg BUILDKIT_INLINE_CACHE=1 \
           \
           --build-arg BUILD_DATE=${BUILD_DATE} \
           --build-arg GITHUB_SHA=${GITHUB_SHA} \