Transport context to all threads

The nova.utils.spawn and spawn_n methods transport
the context (and profiling information) to the
newly created threads. But the same isn't done
when submitting work to thread-pools in the
ComputeManager.

The code doing that for spawn and spawn_n
is extracted to a new function
and called to submit the work to the thread-pools.

Closes-Bug: #1962574
Change-Id: I9085deaa8cf0b167d87db68e4afc4a463c00569c

nova/compute/manager.py

@@ -8621,7 +8621,8 @@ class ComputeManager(manager.Manager):
         # in order to be able to track and abort it in the future.
         self._waiting_live_migrations[instance.uuid] = (None, None)
         try:
-            future = self._live_migration_executor.submit(
+            future = nova.utils.pass_context(
+                self._live_migration_executor.submit,
                 self._do_live_migration, context, dest, instance,
                 block_migration, migration, migrate_data)
             self._waiting_live_migrations[instance.uuid] = (migration, future)
@@ -9866,7 +9867,9 @@ class ComputeManager(manager.Manager):
             else:
                 LOG.debug('Triggering sync for uuid %s', uuid)
                 self._syncs_in_progress[uuid] = True
-                self._sync_power_pool.spawn_n(_sync, db_instance)
+                nova.utils.pass_context(self._sync_power_pool.spawn_n,
+                                        _sync,
+                                        db_instance)
 
     def _query_driver_power_state_and_sync(self, context, db_instance):
         if db_instance.task_state is not None:

nova/conductor/manager.py

@@ -2049,8 +2049,8 @@ class ComputeTaskManager:
                         skipped_host(target_ctxt, host, image_ids)
                         continue
 
-                    fetch_pool.spawn_n(wrap_cache_images, target_ctxt, host,
-                                       image_ids)
+                    utils.pass_context(fetch_pool.spawn_n, wrap_cache_images,
+                                       target_ctxt, host, image_ids)
 
         # Wait until all those things finish
         fetch_pool.waitall()

nova/tests/unit/compute/test_compute_mgr.py

@@ -9154,9 +9154,15 @@ class ComputeManagerMigrationTestCase(test.NoDBTestCase,
         self.assertEqual(driver_console.get_connection_info.return_value,
                          console)
 
+    @mock.patch('nova.utils.pass_context')
     @mock.patch('nova.compute.manager.ComputeManager.'
                 '_do_live_migration')
-    def _test_max_concurrent_live(self, mock_lm):
+    def _test_max_concurrent_live(self, mock_lm, mock_pass_context):
+        # pass_context wraps the function, which doesn't work with a mock
+        # So we simply mock it too
+        def _mock_pass_context(runner, func, *args, **kwargs):
+            return runner(func, *args, **kwargs)
+        mock_pass_context.side_effect = _mock_pass_context
 
         @mock.patch('nova.objects.Migration.save')
         def _do_it(mock_mig_save):

nova/utils.py

@@ -632,15 +632,13 @@ def _serialize_profile_info():
     return trace_info
 
 
-def spawn(func, *args, **kwargs):
-    """Passthrough method for eventlet.spawn.
+def pass_context(runner, func, *args, **kwargs):
+    """Generalised passthrough method
 
-    This utility exists so that it can be stubbed for testing without
-    interfering with the service spawns.
-
-    It will also grab the context from the threadlocal store and add it to
-    the store on the new thread.  This allows for continuity in logging the
-    context when using this method to spawn a new thread.
+    It will grab the context from the threadlocal store and add it to
+    the store on the runner.  This allows for continuity in logging the
+    context when using this method to spawn a new thread through the
+    runner function
     """
     _context = common_context.get_current()
     profiler_info = _serialize_profile_info()
@@ -655,7 +653,21 @@ def spawn(func, *args, **kwargs):
             profiler.init(**profiler_info)
         return func(*args, **kwargs)
 
-    return eventlet.spawn(context_wrapper, *args, **kwargs)
+    return runner(context_wrapper, *args, **kwargs)
+
+
+def spawn(func, *args, **kwargs):
+    """Passthrough method for eventlet.spawn.
+
+    This utility exists so that it can be stubbed for testing without
+    interfering with the service spawns.
+
+    It will also grab the context from the threadlocal store and add it to
+    the store on the new thread.  This allows for continuity in logging the
+    context when using this method to spawn a new thread.
+    """
+
+    return pass_context(eventlet.spawn, func, *args, **kwargs)
 
 
 def spawn_n(func, *args, **kwargs):
@@ -668,25 +680,12 @@ def spawn_n(func, *args, **kwargs):
     the store on the new thread.  This allows for continuity in logging the
     context when using this method to spawn a new thread.
     """
-    _context = common_context.get_current()
-    profiler_info = _serialize_profile_info()
-
-    @functools.wraps(func)
-    def context_wrapper(*args, **kwargs):
-        # NOTE: If update_store is not called after spawn_n it won't be
-        # available for the logger to pull from threadlocal storage.
-        if _context is not None:
-            _context.update_store()
-        if profiler_info and profiler:
-            profiler.init(**profiler_info)
-        func(*args, **kwargs)
-
-    eventlet.spawn_n(context_wrapper, *args, **kwargs)
+    pass_context(eventlet.spawn_n, func, *args, **kwargs)
 
 
 def tpool_execute(func, *args, **kwargs):
     """Run func in a native thread"""
-    tpool.execute(func, *args, **kwargs)
+    return pass_context(tpool.execute, func, *args, **kwargs)
 
 
 def is_none_string(val):