Make build_docker_and_run_tests.sh pass shellcheck (with suppressions)

tools/run_tests/dockerize/build_docker_and_run_tests.sh

@@ -18,7 +18,7 @@
 
 set -ex
 
-cd $(dirname $0)/../../..
+cd "$(dirname "$0")/../../.."
 git_root=$(pwd)
 cd -
 
@@ -35,15 +35,15 @@ mkdir -p /tmp/xdg-cache-home
 # DOCKERHUB_ORGANIZATION - If set, pull a prebuilt image from given dockerhub org.
 
 # Use image name based on Dockerfile location checksum
-DOCKER_IMAGE_NAME=$(basename $DOCKERFILE_DIR)_$(sha1sum $DOCKERFILE_DIR/Dockerfile | cut -f1 -d\ )
+DOCKER_IMAGE_NAME=$(basename "$DOCKERFILE_DIR")_$(sha1sum "$DOCKERFILE_DIR/Dockerfile" | cut -f1 -d\ )
 
 if [ "$DOCKERHUB_ORGANIZATION" != "" ]
 then
   DOCKER_IMAGE_NAME=$DOCKERHUB_ORGANIZATION/$DOCKER_IMAGE_NAME
-  time docker pull $DOCKER_IMAGE_NAME
+  time docker pull "$DOCKER_IMAGE_NAME"
 else
   # Make sure docker image has been built. Should be instantaneous if so.
-  docker build -t $DOCKER_IMAGE_NAME $DOCKERFILE_DIR
+  docker build -t "$DOCKER_IMAGE_NAME" "$DOCKERFILE_DIR"
 fi
 
 # Choose random name for docker container
@@ -54,6 +54,8 @@ docker_instance_git_root=/var/local/jenkins/grpc
 
 # Run tests inside docker
 DOCKER_EXIT_CODE=0
+# TODO: silence complaint about $TTY_FLAG expansion in some other way
+# shellcheck disable=SC2086
 docker run \
   -e "RUN_TESTS_COMMAND=$RUN_TESTS_COMMAND" \
   -e "config=$config" \
@@ -61,7 +63,7 @@ docker run \
   -e CCACHE_DIR=/tmp/ccache \
   -e XDG_CACHE_HOME=/tmp/xdg-cache-home \
   -e THIS_IS_REALLY_NEEDED='see https://github.com/docker/docker/issues/14203 for why docker is awful' \
-  -e HOST_GIT_ROOT=$git_root \
+  -e HOST_GIT_ROOT="$git_root" \
   -e LOCAL_GIT_ROOT=$docker_instance_git_root \
   -e "BUILD_ID=$BUILD_ID" \
   -e "BUILD_URL=$BUILD_URL" \
@@ -70,7 +72,8 @@ docker run \
   -e "KOKORO_BUILD_NUMBER=$KOKORO_BUILD_NUMBER" \
   -e "KOKORO_BUILD_URL=$KOKORO_BUILD_URL" \
   -e "KOKORO_JOB_NAME=$KOKORO_JOB_NAME" \
-  -i $TTY_FLAG \
+  -i \
+  $TTY_FLAG \
   --sysctl net.ipv6.conf.all.disable_ipv6=0 \
   -v ~/.config/gcloud:/root/.config/gcloud \
   -v "$git_root:$docker_instance_git_root" \
@@ -78,18 +81,18 @@ docker run \
   -v /tmp/npm-cache:/tmp/npm-cache \
   -v /tmp/xdg-cache-home:/tmp/xdg-cache-home \
   -w /var/local/git/grpc \
-  --name=$CONTAINER_NAME \
-  $DOCKER_IMAGE_NAME \
+  --name="$CONTAINER_NAME" \
+  "$DOCKER_IMAGE_NAME" \
   bash -l "/var/local/jenkins/grpc/$DOCKER_RUN_SCRIPT" || DOCKER_EXIT_CODE=$?
 
 # use unique name for reports.zip to prevent clash between concurrent
 # run_tests.py runs 
-TEMP_REPORTS_ZIP=`mktemp`
-docker cp "$CONTAINER_NAME:/var/local/git/grpc/reports.zip" ${TEMP_REPORTS_ZIP} || true
-unzip -o ${TEMP_REPORTS_ZIP} -d $git_root || true
-rm -f ${TEMP_REPORTS_ZIP}
+TEMP_REPORTS_ZIP=$(mktemp)
+docker cp "$CONTAINER_NAME:/var/local/git/grpc/reports.zip" "${TEMP_REPORTS_ZIP}" || true
+unzip -o "${TEMP_REPORTS_ZIP}" -d "$git_root" || true
+rm -f "${TEMP_REPORTS_ZIP}"
 
 # remove the container, possibly killing it first
-docker rm -f $CONTAINER_NAME || true
+docker rm -f "$CONTAINER_NAME" || true
 
 exit $DOCKER_EXIT_CODE