[CE-275] Support pulling newer images

Support pulling newer images from dockerhub even local exist.

* Allow pulling newer images even local exist;
* Add `make dockerhub-pull` command for shortcut;
* Update documentation.

Change-Id: I84d6c46781af738a1873f851accb41d5c7662608
Signed-off-by: Baohua Yang <yangbaohua@gmail.com>

Makefile

@@ -12,7 +12,8 @@
 #   - doc:            Start a local web service to explore the documentation
 #   - docker[-clean]: Build/clean docker images locally
 #   - dockerhub:      Build using dockerhub materials, to verify them
-#   - license:		  Checks sourrce files for Apache license header
+#   - dockerhub-pull: Pulling service images from dockerhub
+#   - license:		    Checks sourrce files for Apache license header
 #   - help:           Output the help instructions for each command
 #   - log:            Check the recent log output of all services
 #   - restart:        Stop the cello service and then start
@@ -140,6 +141,9 @@ dockerhub-%: ##@Building latest images with dockerhub materials, to valid them
 	-t $$IMG:x86_64-latest \
 	dockerhub/latest/$$dir
 
+dockerhub-pull: ##@Pull service images from dockerhub
+	cd scripts/master_node && bash download_images.sh
+
 license:
 	bash scripts/check_license.sh
 

docs/setup_master.md

@@ -101,7 +101,7 @@ Cello project also provide Docker images for quick adoptions, users can pull the
 ### Pull from Dockerhub
 The build process is generally expensive so you may wanna just pull those images from Dockerhub.
 
-Run `cd scripts/master_node && bash download_images.sh` will pull the following images:
+Run `make dockerhub-pull` will pull the following images:
 
 * [hyperledger/cello-baseimage](https://hub.docker.com/r/hyperledger/cello-baseimage/): Base images for the service images.
 * [hyperledger/cello-engine](https://hub.docker.com/r/hyperledger/cello-engine/): Docker images for the engine service.
@@ -113,8 +113,7 @@ Run `cd scripts/master_node && bash download_images.sh` will pull the following
 By default, the `latest` version of images will be pulled, and you may optionally specify the version of images to pull down:
 
 ```
-$ cd scripts/master_node
-$ VERSION=0.8.0-beta bash download_images.sh
+$ VERSION=0.8.0-beta make dockerhub-pull
 ```
 
 ### Local Building

scripts/master_node/download_images.sh

@@ -36,13 +36,13 @@ echo_b "Check node:9.2 image."
 
 for IMG in baseimage engine mongo nginx operator-dashboard user-dashboard watchdog ; do
 	HLC_IMG=hyperledger/cello-${IMG}
-	if [ -z "$(docker images -q ${HLC_IMG}:${ARCH}-${VERSION} 2> /dev/null)" ]; then  # not exist
-		echo_b "Pulling ${HLC_IMG}:${ARCH}-${VERSION} from dockerhub"
-		docker pull ${HLC_IMG}:${ARCH}-${VERSION}
-		docker tag ${HLC_IMG}:${ARCH}-${VERSION} ${HLC_IMG}  # match the docker-compose file
-	else
-		echo_g "${HLC_IMG} already exist locally"
-	fi
+	#if [ -z "$(docker images -q ${HLC_IMG}:${ARCH}-${VERSION} 2> /dev/null)" ]; then  # not exist
+	echo_b "Pulling ${HLC_IMG}:${ARCH}-${VERSION} from dockerhub"
+	docker pull ${HLC_IMG}:${ARCH}-${VERSION}
+	docker tag ${HLC_IMG}:${ARCH}-${VERSION} ${HLC_IMG}  # match the docker-compose file
+	#else
+	#	echo_g "${HLC_IMG} already exist locally"
+	#fi
 done
 
 echo_g "All Image downloaded "