openstack/deb-python-taskflow
Code Issues Proposed changes

Notify on task reversion

Browse Source 
When a runner and its associated task are
reverted we should fire off notifications
that this is occuring so that others can
perform various activities when this occurs.

Change-Id: I3fc797255e5cacd0d5cff9cb6ec444ccb9e7ac2e
This commit is contained in:
Joshua Harlow
2013-08-26 16:28:09 -07:00
parent 772c3a8c21
commit f822363afa
6 changed files with 77 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
taskflow/patterns/linear_flow.py
View File

@@ -172,7 +172,7 @@ class Flow(flow.Flow):
# Add the task to be rolled back *immediately* so that even if
# the task fails while producing results it will be given a
# chance to rollback.
rb = utils.RollbackTask(context, runner.task, result=None)
rb = utils.Rollback(context, runner, self, self.task_notifier)
self._accumulator.add(rb)
self.task_notifier.notify(states.STARTED, details={
'context': context,
@@ -198,13 +198,7 @@ class Flow(flow.Flow):
" object: %s", result)
result = exc.InvalidStateException()
raise result
# Adjust the task result in the accumulator before
# notifying others that the task has finished to
# avoid the case where a listener might throw an
# exception.
rb.result = result
runner.result = result
self.results[runner.uuid] = result
self.results[runner.uuid] = runner.result
self.task_notifier.notify(states.SUCCESS, details={
'context': context,
'flow': self,

3
taskflow/patterns/threaded_flow.py
View File

@@ -423,7 +423,8 @@ class Flow(flow.Flow):
accum = utils.RollbackAccumulator()
for r in self._graph.nodes_iter():
if r.has_ran():
accum.add(utils.RollbackTask(context, r.task, r.result))
accum.add(utils.Rollback(context, r,
self, self.task_notifier))
try:
self._change_state(context, states.REVERTING)
accum.rollback(cause)

3
taskflow/states.py
View File

@@ -30,6 +30,7 @@ INTERRUPTED = 'INTERRUPTED'
PENDING = 'PENDING'
RESUMING = 'RESUMING'
REVERTING = 'REVERTING'
REVERTED = 'REVERTED'
RUNNING = RUNNING
STARTED = 'STARTED'
SUCCESS = SUCCESS
@@ -42,3 +43,5 @@ STARTED = STARTED
SUCCESS = SUCCESS
TIMED_OUT = 'TIMED_OUT'
CANCELLED = CANCELLED
REVERTED = REVERTED
REVERTING = REVERTING

28
taskflow/tests/unit/test_linear_flow.py
View File

@@ -16,6 +16,8 @@
# License for the specific language governing permissions and limitations
# under the License.
import collections
from taskflow import decorators
from taskflow import exceptions as exc
from taskflow import states
@@ -135,21 +137,43 @@ class LinearFlowTest(test.TestCase):
wf.add(self.make_reverting_task(i))
run_context = {}
capture_func, captured = self._capture_states()
wf.task_notifier.register('*', capture_func)
wf.run(run_context)
self.assertEquals(10, len(run_context))
self.assertEquals(10, len(captured))
for _k, v in run_context.items():
self.assertEquals('passed', v)
for _uuid, u_states in captured.items():
self.assertEquals([states.STARTED, states.SUCCESS], u_states)
def _capture_states(self):
capture_where = collections.defaultdict(list)
def do_capture(state, details):
runner = details.get('runner')
if not runner:
return
capture_where[runner.uuid].append(state)
return (do_capture, capture_where)
def test_reverting_flow(self):
wf = lw.Flow("the-test-action")
wf.add(self.make_reverting_task(1))
wf.add(self.make_reverting_task(2, True))
ok_uuid = wf.add(self.make_reverting_task(1))
broke_uuid = wf.add(self.make_reverting_task(2, True))
capture_func, captured = self._capture_states()
wf.task_notifier.register('*', capture_func)
run_context = {}
self.assertRaises(Exception, wf.run, run_context)
self.assertEquals('reverted', run_context[1])
self.assertEquals(1, len(run_context))
self.assertEquals([states.STARTED, states.SUCCESS, states.REVERTING,
states.REVERTED], captured[ok_uuid])
self.assertEquals([states.STARTED, states.FAILURE, states.REVERTING,
states.REVERTED], captured[broke_uuid])
def test_not_satisfied_inputs_previous(self):
wf = lw.Flow("the-test-action")

4
taskflow/tests/unit/test_threaded_flow.py
View File

@@ -327,7 +327,7 @@ class ThreadedFlowTest(test.TestCase):
context = {}
self.assertRaises(IOError, flo.run, context)
self.assertEquals(states.FAILURE, flo.state)
self.assertEquals(states.FAILURE, history[f_uuid][-1])
self.assertEquals(states.REVERTED, history[f_uuid][-1])
self.assertTrue(context.get('reverted'))
def test_failure_cancel_successors(self):
@@ -351,7 +351,7 @@ class ThreadedFlowTest(test.TestCase):
context = {}
self.assertRaises(IOError, flo.run, context)
self.assertEquals(states.FAILURE, flo.state)
self.assertEquals(states.FAILURE, history[fq][-1])
self.assertEquals(states.REVERTED, history[fq][-1])
self.assertEquals(states.CANCELLED, history[af][-1])
self.assertEquals(states.CANCELLED, history[af2][-1])

63
taskflow/utils.py
View File

@@ -25,12 +25,14 @@ import logging
import threading
import time
import types
import weakref
import threading2
from distutils import version
from taskflow.openstack.common import uuidutils
from taskflow import states
TASK_FACTORY_ATTRIBUTE = '_TaskFlow_task_factory'
LOG = logging.getLogger(__name__)
@@ -263,32 +265,10 @@ class FlowFailure(object):
return self.runner.exc_info[1]
class RollbackTask(object):
"""A helper task that on being called will call the underlying callable
tasks revert method (if said method exists).
"""
def __init__(self, context, task, result):
self.task = task
self.result = result
self.context = context
def __str__(self):
return str(self.task)
def __call__(self, cause):
if ((hasattr(self.task, "revert") and
isinstance(self.task.revert, collections.Callable))):
self.task.revert(self.context, self.result, cause)
class Runner(object):
"""A helper class that wraps a task and can find the needed inputs for
the task to run, as well as providing a uuid and other useful functionality
for users of the task.
TODO(harlowja): replace with the task details object or a subclass of
that???
"""
def __init__(self, task, uuid=None):
@@ -332,7 +312,9 @@ class Runner(object):
@property
def name(self):
if hasattr(self.task, 'name'):
return self.task.name
return '?'
def reset(self):
self.result = None
@@ -452,6 +434,43 @@ class TransitionNotifier(object):
break
class Rollback(object):
"""A helper functor object that on being called will call the underlying
runners tasks revert method (if said method exists) and do the appropriate
notification to signal to others that the reverting is underway.
"""
def __init__(self, context, runner, flow, notifier):
self.runner = runner
self.context = context
self.notifier = notifier
# Use weak references to give the GC a break.
self.flow = weakref.proxy(flow)
def __str__(self):
return "Rollback: %s" % (self.runner)
def _fire_notify(self, has_reverted):
if self.notifier:
if has_reverted:
state = states.REVERTED
else:
state = states.REVERTING
self.notifier.notify(state, details={
'context': self.context,
'flow': self.flow,
'runner': self.runner,
})
def __call__(self, cause):
self._fire_notify(False)
task = self.runner.task
if ((hasattr(task, "revert") and
isinstance(task.revert, collections.Callable))):
task.revert(self.context, self.runner.result, cause)
self._fire_notify(True)
class RollbackAccumulator(object):
"""A utility class that can help in organizing 'undo' like code
so that said code be rolled back on failure (automatically or manually)