ADD: added new version of protobuf

libs/protobuf/kokoro/linux/dockerfile/push_testing_images.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+set -ex
+
+cd $(dirname $0)/../../..
+git_root=$(pwd)
+cd kokoro/linux/dockerfile
+
+DOCKERHUB_ORGANIZATION=protobuftesting
+
+for DOCKERFILE_DIR in test/*
+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\ )
+
+  echo $DOCKER_IMAGE_NAME
+  # skip the image if it already exists in the repo
+  curl --silent -f -lSL https://registry.hub.docker.com/v2/repositories/${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