Quote docker .data-root in jq expression

Author: keithduncan

packer/linux/conf/bin/bk-check-disk-space.sh

@@ -4,7 +4,7 @@ set -euo pipefail
 DISK_MIN_AVAILABLE=${DISK_MIN_AVAILABLE:-5242880} # 5GB
 DISK_MIN_INODES=${DISK_MIN_INODES:-250000} # docker needs lots
 
-DOCKER_DIR="/var/lib/docker/"
+DOCKER_DIR="$(jq -r '."data-root" // "/var/lib/docker"' /etc/docker/daemon.json)"
 
 disk_avail=$(df -k --output=avail "$DOCKER_DIR" | tail -n1)
 

packer/linux/conf/bin/bk-configure-docker.sh

@@ -20,5 +20,5 @@ fi
 
 # Move docker root to the ephemeral device
 if [[ "${BUILDKITE_ENABLE_INSTANCE_STORAGE:-false}" == "true" ]] ; then
-  cat <<< "$(jq '.data-root="/mnt/ephemeral/docker"' /etc/docker/daemon.json)" > /etc/docker/daemon.json
+  cat <<< "$(jq '."data-root"="/mnt/ephemeral/docker"' /etc/docker/daemon.json)" > /etc/docker/daemon.json
 fi