Merge pull request #120 from cisagov/improvement/add_script_to_update_molecule_images

Add a convenience script to update molecule Docker images

Author: mcdonnnj

update_molecule_images.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+
+# Update the Docker images used in the molecule testing for this role.
+# Please note that this script requires the yq tool
+# (https://github.com/mikefarah/yq) which can be installed from brew as
+# yq and is available on Arch as go-yq.
+
+set -o nounset
+set -o errexit
+set -o pipefail
+
+# Print usage information and exit.
+function usage {
+  echo "Usage:"
+  echo "  ${0##*/} [source_file]"
+  echo
+  echo "Arguments:"
+  echo "  source_file  If specified use this file instead of the default"
+  echo "               molecule/default/molecule.yml"
+  exit 1
+}
+
+# Check for required external programs. If any are missing output a list of all
+# requirements and then exit.
+function check_dependencies {
+  if [ -z "$(command -v yq)" ]; then
+    echo "This script requires the following tools to run:"
+    echo "- yq"
+    exit 1
+  fi
+}
+
+if [ $# -gt 1 ]; then
+  usage
+fi
+
+if [ $# -eq 1 ]; then
+  source_file="$1"
+else
+  source_file="molecule/default/molecule.yml"
+fi
+
+check_dependencies
+
+yq '.platforms[].image' < "$source_file" | xargs -n 1 docker pull