Add option to specify group ID

lib/template.js

@@ -95,6 +95,7 @@ const pkg = require(path.resolve(__dirname, '..', 'package.json'));
  * of 1-minute periods before an alarm is triggered. The default is 1 period, or
  * 1 minute. This parameter can be provided as either a number or a reference,
  * i.e. `{"Ref": "..."}`.
+ * @param {Number|ref} [options.gid] - Use this group ID for the worker child process.
  */
 module.exports = (options = {}) => {
   ['service', 'serviceVersion', 'command', 'cluster'].forEach((required) => {
@@ -133,7 +134,8 @@ module.exports = (options = {}) => {
       [
         { Name: 'WorkTopic', Value: cf.ref(prefixed('Topic')) },
         { Name: 'QueueUrl', Value: cf.ref(prefixed('Queue')) },
-        { Name: 'Volumes', Value: mountPoints.map((m) => m.ContainerPath).join(',') }
+        { Name: 'Volumes', Value: mountPoints.map((m) => m.ContainerPath).join(',') },
+        { Name: 'GroupID', Value: options.gid || '' }
       ]
     );
   };

lib/worker.js

@@ -66,6 +66,8 @@ class Worker {
       // An arbitrarily chosen UID of a non-existent user
       uid: 200
     };
+    // If group id is specified, add the group id
+    if (process.env.GroupID) options.gid = Number(process.env.GroupID);
 
     try {
       const results = await child(this.command, options, this.logger);