Add progress indicator to batch execution.

Also disable Execute button immediately when clicked.

tailbone/templates/batch/view.mako

@@ -1,3 +1,27 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="/batch/crud.mako" />
+
+<%def name="head_tags()">
+  ${parent.head_tags()}
+  <script type="text/javascript">
+    $(function() {
+        $('#execute-batch').click(function() {
+            $(this).button('option', 'label', "Executing, please wait...").button('disable');
+            location.href = '${url('{0}.execute'.format(route_prefix), uuid=batch.uuid)}';
+        });
+    });
+  </script>
+</%def>
+
+<%def name="buttons()">
+    <div class="buttons">
+      % if not form.readonly and batch.refreshable:
+          ${h.submit('save-refresh', "Save & Refresh Data")}
+      % endif
+      % if not batch.executed and request.has_perm('{0}.execute'.format(permission_prefix)):
+          <button type="button" id="execute-batch"${'' if execute_enabled else ' disabled="disabled"'}>${execute_title}</button>
+      % endif
+    </div>
+</%def>
+
 ${parent.body()}

tailbone/views/batch.py

@@ -647,12 +647,63 @@ class BatchCrud(BaseCrud):
         return self.request.route_url('{0}.refresh'.format(self.route_prefix), uuid=uuid)
 
     def execute(self):
+        """
+        Execute a batch.  Starts a separate thread for the execution, and
+        displays a progress indicator page.
+        """
         batch = self.current_batch()
-        if self.handler.execute(batch):
+
+        key = '{0}.execute'.format(self.batch_class.__tablename__)
+        progress = SessionProgress(self.request, key)
+        thread = Thread(target=self.execute_thread, args=(batch.uuid, progress))
+        thread.start()
+
+        kwargs = {
+            'key': key,
+            'cancel_url': self.view_url(batch.uuid),
+            'cancel_msg': "Batch execution was canceled.",
+            }
+        return render_to_response('/progress.mako', kwargs, request=self.request)
+
+    def execute_thread(self, batch_uuid, progress=None):
+        """
+        Thread target for executing a batch with progress indicator.
+        """
+        # Execute the batch, with progress.  Note that we must use the rattail
+        # session here; can't use tailbone because it has web request
+        # transaction binding etc.
+        session = RatSession()
+        batch = session.query(self.batch_class).get(batch_uuid)
+        try:
+            result = self.handler.execute(batch, progress=progress)
+
+        # If anything goes wrong, rollback and log the error etc.
+        except Exception as error:
+            session.rollback()
+            log.exception("execution failed for batch: {0}".format(batch))
+            session.close()
+            if progress:
+                progress.session.load()
+                progress.session['error'] = True
+                progress.session['error_msg'] = "Batch execution failed: {0}".format(error)
+                progress.session.save()
+
+        # If no error, check result flag (false means user canceled).
+        else:
+            if result:
                 batch.executed = datetime.datetime.utcnow()
                 batch.executed_by = self.request.user
-            self.request.session.flash("Batch was executed successfully.")
+                session.commit()
-        return HTTPFound(location=self.view_url(batch.uuid))
+            else:
+                session.rollback()
+            session.refresh(batch)
+            session.close()
+
+            if progress:
+                progress.session.load()
+                progress.session['complete'] = True
+                progress.session['success_url'] = self.view_url(batch.uuid)
+                progress.session.save()
         
 
 class FileBatchCrud(BatchCrud):