Here is one similar oslo.messaging bug: https://bugs.launchpad.net/oslo.messaging/+bug/1288878

monkey_patch thread is needed when using oslo.message. the behavior is unknown and in risk if thread is set to False.

In my local development, the task will run successfully and report state is SUCCESS. However, the oslo messaging exception can also be seen.

========

Workflow:
  tasks:
    task1:
      action: std.echo
      parameters:
        output: "Hello, World"


and test log:

2014-07-18 15:15:12.286 11358 INFO workflow_trace [-] New execution started - [workbook_name = 'myBook', task_name = 'task1']
2014-07-18 15:15:12.405 11358 INFO mistral.engine.drivers.default.engine [-] Submitted task for execution: 'e7fc79c4-a2cc-461f-a291-4ab04c536e76'
localhost.localdomain - - [18/Jul/2014 15:15:12] "POST /v1/workbooks/myBook/executions HTTP/1.1" 201 127
2014-07-18 15:15:12.427 11358 INFO mistral.actions.std_actions [-] Running echo action [output=Hello, World]
2014-07-18 15:15:12.466 11358 INFO workflow_trace [-] Task 'task1' [RUNNING -> SUCCESS, result = Hello, World]
2014-07-18 15:15:12.494 11358 DEBUG mistral.engine.workflow [-] Recieved task task1: SUCCESS find_tasks_after_completion /home/ray/git/mistral/mistral/engine/workflow.py:87
2014-07-18 15:15:12.499 11358 DEBUG mistral.engine.workflow [-] Found tasks: [] find_tasks_after_completion /home/ray/git/mistral/mistral/engine/workflow.py:104
2014-07-18 15:15:12.499 11358 DEBUG mistral.engine.workflow [-] Workflow tasks to schedule: [] find_tasks_after_completion /home/ray/git/mistral/mistral/engine/workflow.py:110
2014-07-18 15:15:12.507 11358 INFO workflow_trace [-] Execution 'c415b3f2-e3f9-44b0-808a-1eae5c127d8c' [RUNNING -> SUCCESS]
2014-07-18 15:15:12.511 11358 INFO mistral.engine [-] Changed execution state: {'workbook_name': u'myBook', 'task': u'task1', 'updated_at': None, 'id': u'c415b3f2-e3f9-44b0-808a-1eae5c127d8c', 'created_at': '2014-07-18 07:15:12.323775', 'state': 'SUCCESS', 'context': {}}
2014-07-18 15:15:12.548 11358 ERROR oslo.messaging.rpc.dispatcher [-] Exception during message handling: _oslo_messaging_localcontext_08abad06ee4d4a1dbe063092efdf276b
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher Traceback (most recent call last):
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher   File "/home/ray/git/mistral/.tox/venv/lib/python2.7/site-packages/oslo/messaging/rpc/dispatcher.py", line 133, in _dispatch_and_reply
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher     incoming.message))
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher   File "/home/ray/git/mistral/.tox/venv/lib/python2.7/site-packages/oslo/messaging/rpc/dispatcher.py", line 178, in _dispatch
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher     localcontext.clear_local_context()
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher   File "/home/ray/git/mistral/.tox/venv/lib/python2.7/site-packages/oslo/messaging/localcontext.py", line 55, in clear_local_context
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher     delattr(_STORE, _KEY)
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher AttributeError: _oslo_messaging_localcontext_08abad06ee4d4a1dbe063092efdf276b
2014-07-18 15:15:12.548 11358 TRACE oslo.messaging.rpc.dispatcher 
2014-07-18 15:15:12.579 11358 ERROR oslo.messaging._drivers.common [-] Returning exception _oslo_messaging_localcontext_08abad06ee4d4a1dbe063092efdf276b to caller
2014-07-18 15:15:12.579 11358 ERROR oslo.messaging._drivers.common [-] ['Traceback (most recent call last):\n', '  File "/home/ray/git/mistral/.tox/venv/lib/python2.7/site-packages/oslo/messaging/rpc/dispatcher.py", line 133, in _dispatch_and_reply\n    incoming.message))\n', '  File "/home/ray/git/mistral/.tox/venv/lib/python2.7/site-packages/oslo/messaging/rpc/dispatcher.py", line 178, in _dispatch\n    localcontext.clear_local_context()\n', '  File "/home/ray/git/mistral/.tox/venv/lib/python2.7/site-packages/oslo/messaging/localcontext.py", line 55, in clear_local_context\n    delattr(_STORE, _KEY)\n', 'AttributeError: _oslo_messaging_localcontext_08abad06ee4d4a1dbe063092efdf276b\n']