Smaller docker image (#12824)

* build: makes the grafana docker image smaller.

* build: branches and PR:s builds the docker image.

.circleci/config.yml

@@ -194,6 +194,18 @@ jobs:
       - run: cp dist/grafana-latest.linux-x64.tar.gz packaging/docker
       - run: cd packaging/docker && ./build-deploy.sh "master-${CIRCLE_SHA1}"
 
+  grafana-docker-pr:
+    docker:
+      - image: docker:stable-git
+    steps:
+      - checkout
+      - attach_workspace:
+          at: .
+      - setup_remote_docker
+      - run: docker info
+      - run: cp dist/grafana-latest.linux-x64.tar.gz packaging/docker
+      - run: cd packaging/docker && ./build.sh "${CIRCLE_SHA1}"
+
   grafana-docker-release:
       docker:
         - image: docker:stable-git
@@ -387,3 +399,13 @@ workflows:
             filters: *filter-not-release-or-master
         - postgres-integration-test:
             filters: *filter-not-release-or-master
+        - grafana-docker-pr:
+            requires:
+              - build
+              - test-backend
+              - test-frontend
+              - codespell
+              - gometalinter
+              - mysql-integration-test
+              - postgres-integration-test
+            filters: *filter-not-release-or-master

packaging/docker/Dockerfile

@@ -1,6 +1,17 @@
 FROM debian:stretch-slim
 
 ARG GRAFANA_TGZ="grafana-latest.linux-x64.tar.gz"
+
+RUN apt-get update && apt-get install -qq -y tar && \
+    apt-get autoremove -y && \
+    rm -rf /var/lib/apt/lists/*
+
+COPY ${GRAFANA_TGZ} /tmp/grafana.tar.gz
+
+RUN mkdir /tmp/grafana && tar xfvz /tmp/grafana.tar.gz --strip-components=1 -C /tmp/grafana
+
+FROM debian:stretch-slim
+
 ARG GF_UID="472"
 ARG GF_GID="472"
 
@@ -12,15 +23,13 @@ ENV PATH=/usr/share/grafana/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bi
     GF_PATHS_PLUGINS="/var/lib/grafana/plugins" \
     GF_PATHS_PROVISIONING="/etc/grafana/provisioning"
 
-RUN apt-get update && apt-get install -qq -y tar libfontconfig ca-certificates && \
+RUN apt-get update && apt-get install -qq -y libfontconfig ca-certificates && \
     apt-get autoremove -y && \
     rm -rf /var/lib/apt/lists/*
 
-COPY ${GRAFANA_TGZ} /tmp/grafana.tar.gz
+COPY --from=0 /tmp/grafana "$GF_PATHS_HOME"
 
 RUN mkdir -p "$GF_PATHS_HOME/.aws" && \
-    tar xfvz /tmp/grafana.tar.gz --strip-components=1 -C "$GF_PATHS_HOME" && \
-    rm /tmp/grafana.tar.gz && \
     groupadd -r -g $GF_GID grafana && \
     useradd -r -u $GF_UID -g grafana grafana && \
     mkdir -p "$GF_PATHS_PROVISIONING/datasources" \