Updated CI to take advantage of cache building

.gitlab-ci.yml

@@ -6,7 +6,7 @@ stages:
 
 variables:
   VERSION: 7.1-fpm-plus
-  DOCKER_IMAGE: leenooks/php
+  CACHETAG: build
   DOCKER_REGISTRY: registry.leenooks.net
   DOCKER_HOST: tcp://${DOCKER_REGISTRY}-leenooks-ci-docker:2375
 
@@ -23,7 +23,7 @@ test:
   script:
   - cat /etc/hosts
   - env|sort
-  - docker build -t ${DOCKER_IMAGE}:${VERSION} .
+  - docker build -t ${CI_REGISTRY_IMAGE}:${VERSION} .
   - docker images
   only:
   - debug
@@ -31,9 +31,10 @@ test:
 build:
   stage: build
   script:
-  - docker build -t ${DOCKER_IMAGE}:${VERSION} .
-  - docker tag ${DOCKER_IMAGE}:${VERSION} ${DOCKER_REGISTRY}/${DOCKER_IMAGE}:${VERSION}
-  - docker push ${DOCKER_REGISTRY}/${DOCKER_IMAGE}:${VERSION}
+  - docker pull ${CI_REGISTRY_IMAGE}:${CACHETAG} || true
+  - docker build --cache-from ${CI_REGISTRY_IMAGE}:${CACHETAG} -t ${CI_REGISTRY_IMAGE}:${VERSION} -t ${CI_REGISTRY_IMAGE}:${CACHETAG} .
+  - docker push ${CI_REGISTRY_IMAGE}:${VERSION}
+  - docker push ${CI_REGISTRY_IMAGE}:${CACHETAG}
   tags:
   - docker
   only: