openstack/deb-python-taskflow
Code Issues Proposed changes

Rework due to code comments.

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This commit is contained in:
Joshua Harlow
2013-05-14 15:24:12 -07:00
parent 7999de8de7
commit 31b91e758e
2 changed files with 59 additions and 25 deletions
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4
taskflow/backends/memory.py
View File

@@ -27,6 +27,7 @@ from taskflow import exceptions as exc
from taskflow import job
from taskflow import jobboard
from taskflow import logbook
from taskflow import states
from taskflow import utils
LOG = logging.getLogger(__name__)
@@ -165,6 +166,9 @@ class MemoryJobBoard(jobboard.JobBoard):
break
if not exists:
raise exc.JobNotFound()
if j.state not in (states.SUCCESS, states.FAILURE):
raise exc.InvalidStateException("Can not delete a job in "
"state %s" % (j.state))
self._board = [(d, j) for (d, j) in self._board if j != job]
@check_not_closed

80
taskflow/patterns/linear_workflow.py
View File

@@ -77,21 +77,50 @@ class Workflow(object):
else:
result_fetcher = None
self.state = states.STARTED
for task in self.tasks:
self._change_state(context, states.STARTED)
# TODO(harlowja): we can likely add in custom reconcilation strategies
# here or around here...
def do_rollback_for(task, ex):
self._change_state(context, states.REVERTING)
with excutils.save_and_reraise_exception():
try:
self._on_task_error(context, task)
except Exception:
LOG.exception("Dropping exception catched when"
" notifying about existing task"
" exception.")
self.rollback(context, exc.TaskException(task, self, ex))
self._change_state(context, states.FAILURE)
self._change_state(context, states.RESUMING)
last_task = 0
if result_fetcher:
for (i, task) in enumerate(self.tasks):
(has_result, result) = result_fetcher(context, self, task)
if not has_result:
break
# Fake running the task so that we trigger the same
# notifications and state changes (and rollback that would
# have happened in a normal flow).
last_task = i + 1
try:
self._on_task_start(context, task)
# Keep a pristine copy of the result
# so that if said result is altered by other further
# states the one here will not be. This ensures that
# if rollback occurs that the task gets exactly the
# result it returned and not a modified one.
self.results.append((task, copy.deepcopy(result)))
self._on_task_finish(context, task, result)
except Exception as ex:
do_rollback_for(task, ex)
self._change_state(context, states.RUNNING)
for task in self.tasks[last_task:]:
try:
# See if we have already ran this.
result = None
has_result = False
if result_fetcher:
(has_result, result) = result_fetcher(context, self, task)
if not has_result:
self.state = state.RUNNING
else:
self.state = state.RESUMING
self._on_task_start(context, task)
if not has_result:
result = task.apply(context, *args, **kwargs)
result = task.apply(context, *args, **kwargs)
# Keep a pristine copy of the result
# so that if said result is altered by other further states
# the one here will not be. This ensures that if rollback
@@ -100,19 +129,20 @@ class Workflow(object):
self.results.append((task, copy.deepcopy(result)))
self._on_task_finish(context, task, result)
except Exception as ex:
self.state = states.FAILURE
with excutils.save_and_reraise_exception():
try:
self._on_task_error(context, task)
except Exception:
LOG.exception("Dropping exception catched when"
" notifying about existing task"
" exception.")
self.state = states.REVERTING
self.rollback(context, exc.TaskException(task, self, ex))
self.state = states.FAILURE
do_rollback_for(task, ex)
# Only gets here if everything went successfully.
self.state = states.SUCCESS
self._change_state(context, states.SUCCESS)
def _change_state(self, context, new_state):
if self.state != new_state:
self.state = new_state
self._on_flow_state_change(context)
def _on_flow_state_change(self, context):
# Notify any listeners that the internal state has changed.
for i in self.listeners:
i.notify(context, self)
def _on_task_error(self, context, task):
# Notify any listeners that the task has errored.