add script for pushing testing docker images

tools/dockerfile/push_testing_images.sh

+#!/bin/bash
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Builds selected testing docker images and pushes them to dockerhub.
+# Useful for testing environments where it's impractical (or impossible)
+# to rely on docker images being cached locally after they've been built
+# for the first time (which might be costly especially for some images).
+# NOTE: gRPC docker images intended to be used by end users are NOT
+# pushed using this script (they're built automatically by dockerhub).
+# This script is only for "internal" images we use when testing gRPC.  
+
+set -ex
+
+cd $(dirname $0)/../..
+git_root=$(pwd)
+cd -
+
+DOCKERHUB_ORGANIZATION=grpctesting
+
+for DOCKERFILE_DIR in tools/dockerfile/test/fuzzer
+do
+  # Generate image name based on Dockerfile checksum. That works well as long
+  # as can count on dockerfiles being written in a way that changing the logical 
+  # contents of the docker image always changes the SHA (e.g. using "ADD file" 
+  # cmd in the dockerfile in not ok as contents of the added file will not be
+  # reflected in the SHA).
+  DOCKER_IMAGE_NAME=$(basename $DOCKERFILE_DIR)_$(sha1sum $DOCKERFILE_DIR/Dockerfile | cut -f1 -d\ )
+
+  # skip the image if it already exists in the repo 
+  curl --silent -f -lSL https://registry.hub.docker.com/v2/repositories/${DOCKERHUB_ORGANIZATION}/${DOCKER_IMAGE_NAME}/tags/latest > /dev/null \
+      && continue
+
+  docker build -t ${DOCKERHUB_ORGANIZATION}/${DOCKER_IMAGE_NAME} ${DOCKERFILE_DIR}
+      
+  # "docker login" needs to be run in advance
+  docker push ${DOCKERHUB_ORGANIZATION}/${DOCKER_IMAGE_NAME}
+done