XenAPI was not implemented to allow for multiple simultaneous XenAPI requests. A single XenAPIConnection (and thus XenAPISession) is used for all queries. XenAPISession's wait_for_task method would set a self.loop = for looping calls to _poll_task until task completion. Subsequent (parallel) calls to wait_for_task for another query would overwrite this. XenAPISession._poll_task was pulled into the XenAPISession.wait_for_task method to avoid having to store self.loop.

nova/tests/test_xenapi.py

@@ -16,6 +16,7 @@
 
 """Test suite for XenAPI."""
 
+import eventlet
 import functools
 import json
 import os
@@ -198,6 +199,28 @@ class XenAPIVMTestCase(test.TestCase):
         self.context = context.RequestContext('fake', 'fake', False)
         self.conn = xenapi_conn.get_connection(False)
 
+    def test_parallel_builds(self):
+        stubs.stubout_loopingcall_delay(self.stubs)
+
+        def _do_build(id, proj, user, *args):
+            values = {
+                'id': id,
+                'project_id': proj,
+                'user_id': user,
+                'image_id': 1,
+                'kernel_id': 2,
+                'ramdisk_id': 3,
+                'instance_type_id': '3',  # m1.large
+                'mac_address': 'aa:bb:cc:dd:ee:ff',
+                'os_type': 'linux'}
+            instance = db.instance_create(self.context, values)
+            self.conn.spawn(instance)
+
+        gt1 = eventlet.spawn(_do_build, 1, self.project.id, self.user.id)
+        gt2 = eventlet.spawn(_do_build, 2, self.project.id, self.user.id)
+        gt1.wait()
+        gt2.wait()
+
     def test_list_instances_0(self):
         instances = self.conn.list_instances()
         self.assertEquals(instances, [])

nova/tests/xenapi/stubs.py

@@ -16,6 +16,7 @@
 
 """Stubouts, mocks and fixtures for the test suite"""
 
+import eventlet
 from nova.virt import xenapi_conn
 from nova.virt.xenapi import fake
 from nova.virt.xenapi import volume_utils
@@ -28,29 +29,6 @@ def stubout_instance_snapshot(stubs):
     @classmethod
     def fake_fetch_image(cls, session, instance_id, image, user, project,
                          type):
-        # Stubout wait_for_task
-        def fake_wait_for_task(self, task, id):
-            class FakeEvent:
-
-                def send(self, value):
-                    self.rv = value
-
-                def wait(self):
-                    return self.rv
-
-            done = FakeEvent()
-            self._poll_task(id, task, done)
-            rv = done.wait()
-            return rv
-
-        def fake_loop(self):
-            pass
-
-        stubs.Set(xenapi_conn.XenAPISession, 'wait_for_task',
-                  fake_wait_for_task)
-
-        stubs.Set(xenapi_conn.XenAPISession, '_stop_loop', fake_loop)
-
         from nova.virt.xenapi.fake import create_vdi
         name_label = "instance-%s" % instance_id
         #TODO: create fake SR record
@@ -63,11 +41,6 @@ def stubout_instance_snapshot(stubs):
 
     stubs.Set(vm_utils.VMHelper, 'fetch_image', fake_fetch_image)
 
-    def fake_parse_xmlrpc_value(val):
-        return val
-
-    stubs.Set(xenapi_conn, '_parse_xmlrpc_value', fake_parse_xmlrpc_value)
-
     def fake_wait_for_vhd_coalesce(session, instance_id, sr_ref, vdi_ref,
                               original_parent_uuid):
         from nova.virt.xenapi.fake import create_vdi
@@ -144,6 +117,16 @@ def stubout_loopingcall_start(stubs):
     stubs.Set(utils.LoopingCall, 'start', fake_start)
 
 
+def stubout_loopingcall_delay(stubs):
+    def fake_start(self, interval, now=True):
+        self._running = True
+        eventlet.sleep(1)
+        self.f(*self.args, **self.kw)
+        # This would fail before parallel xenapi calls were fixed
+        assert self._running == False
+    stubs.Set(utils.LoopingCall, 'start', fake_start)
+
+
 class FakeSessionForVMTests(fake.SessionBase):
     """ Stubs out a XenAPISession for VM tests """
     def __init__(self, uri):