Pass batch execution kwargs when doing that via subprocess

i.e. instead of the normal in-app method

tailbone/views/batch/core.py

@@ -28,6 +28,7 @@ from __future__ import unicode_literals, absolute_import
 
 import os
 import sys
+import json
 import datetime
 import logging
 import socket
@@ -804,7 +805,9 @@ class BatchMasterView(MasterView):
             thread.start()
 
             # launch thread to invoke handler action
-            thread = Thread(target=self.action_subprocess_thread, args=(batch.uuid, port, username, batch_action, progress))
+            thread = Thread(target=self.action_subprocess_thread,
+                            args=(batch.uuid, port, username, batch_action, progress),
+                            kwargs=kwargs)
             thread.start()
 
         else: # either versioning is disabled, or handler doesn't mind
@@ -919,7 +922,7 @@ class BatchMasterView(MasterView):
         log.debug("launching command in subprocess: %s", cmd)
         subprocess.check_call(cmd)
 
-    def action_subprocess_thread(self, batch_uuid, port, username, action, progress):
+    def action_subprocess_thread(self, batch_uuid, port, username, action, progress, **kwargs):
         """
         This method is sort of an alternative thread target for batch actions,
         to be used in the event versioning is enabled for the main process but
@@ -927,6 +930,18 @@ class BatchMasterView(MasterView):
         launch a separate process with versioning disabled in order to act on
         the batch.
         """
+        # figure out the (sub)command args we'll be passing
+        subargs = [
+            '--batch-type',
+            self.handler.batch_key,
+            batch_uuid,
+        ]
+        if action == 'execute' and kwargs:
+            subargs.extend([
+                '--kwargs',
+                json.dumps(kwargs),
+            ])
+
         # invoke command to act on batch in separate process
         try:
             self.launch_subprocess(port=port, username=username,
@@ -935,11 +950,7 @@ class BatchMasterView(MasterView):
                                        '--no-versioning',
                                    ],
                                    subcommand='{}-batch'.format(action),
-                                   subcommand_args=[
-                                       '--batch-type',
-                                       self.handler.batch_key,
-                                       batch_uuid,
-                                   ])
+                                   subcommand_args=subargs)
         except Exception as error:
             log.warning("%s of '%s' batch failed: %s", action, self.handler.batch_key, batch_uuid, exc_info=True)