Check image age to see if it needs updating

cli/resource/init/mango.sh

@@ -3,6 +3,8 @@
 # Wrapper that runs Mango using Docker. Arguments are passed on to Mango CLI.
 # A continuously-running daemon container is started, if it is not running.
 
+# Configuration is done through environment variables
+
 if [ -z "$PROJECT_NAME" ];
 then
     PROJECT_NAME="$(basename "$(pwd)")"
@@ -13,13 +15,36 @@ then
     MANGO_DOCKER_IMAGE="mangocode/mango:latest"
 fi
 
+#TODO @mark: cache dir etc, from Mango itself during init? but that'd make the wrapper platform-dependent
+
+
+# Docker & image
 
 if ! command -v docker 1> /dev/null 2> /dev/null
 then
     echo "Docker must be installed to run Mango"
     exit 1
 fi
 
+img_date="$(docker inspect -f '{{ .Created }}' "$MANGO_DOCKER_IMAGE" 2> /dev/null)"
+if [ $? -ne 0 ] || [ -z "$img_date" ]
+then
+    printf 'pulling docker image %s\n' "$MANGO_DOCKER_IMAGE"
+    docker pull "$MANGO_DOCKER_IMAGE"
+fi
+img_ts="$(date +%s -d $img_date)"
+age_s="$(expr "$(date +%s)" - "$img_ts")"
+echo "age is $age_s s"
+if [ $age_s -gt 43200 ]
+then
+    printf 'updating docker image %s\n' "$MANGO_DOCKER_IMAGE"
+    docker pull "$MANGO_DOCKER_IMAGE"
+fi
+
+# Mango daemon
+
+set -eu
+
 docker run \
     --name "mangod-$PROJECT_NAME" \
     --rm \