openstack/mistral
Code Issues Proposed changes

Towards non-locking model: removing env update from WF controller

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* Removed updating task execution environment from WF controller
  completely and moving it to Workflow class. It was wrong for a
  number of reasons. For example, from architectural perspective
  workflow controller must not update any DB objects, it doesn't
  have such a responsibility and priviledge.

Change-Id: I69a2de97933638d0c4adde443dc67d60893c7d45
This commit is contained in:
Renat Akhmerov
2016-08-01 18:49:37 +07:00
parent abe5ef9634
commit d9c9df2f7d
4 changed files with 31 additions and 39 deletions
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35
mistral/workflow/base.py
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@@ -85,36 +85,29 @@ class WorkflowController(object):
self.wf_spec = wf_spec
@staticmethod
def _update_task_ex_env(task_ex, env):
if not env:
return task_ex
task_ex.in_context['__env'] = u.merge_dicts(
task_ex.in_context['__env'],
env
)
return task_ex
@profiler.trace('workflow-controller-continue-workflow')
def continue_workflow(self, env=None):
def continue_workflow(self):
"""Calculates a list of commands to continue the workflow.
Given a workflow specification this method makes required analysis
according to this workflow type rules and identifies a list of
commands needed to continue the workflow.
:param env: A set of environment variables to overwrite.
:return: List of workflow commands (instances of
mistral.workflow.commands.WorkflowCommand).
"""
# TODO(rakhmerov): We now use this method for two cases:
# 1) to handle task completion
# 2) to resume a workflow after it's been paused
# Moving forward we need to introduce a separate method for
# resuming a workflow because it won't be operating with
# any concrete tasks that caused this operation.
if self._is_paused_or_completed():
return []
# TODO(rakhmerov): Get rid of 'env' parameter completely, WF controller
# should not be updating any DB objects.
return self._find_next_commands(env=env)
return self._find_next_commands()
def rerun_tasks(self, task_execs, reset=True):
"""Gets commands to rerun existing task executions.
@@ -197,13 +190,12 @@ class WorkflowController(object):
raise NotImplementedError
@abc.abstractmethod
def _find_next_commands(self, env=None):
def _find_next_commands(self):
"""Finds commands that should run next.
A concrete algorithm of finding such tasks depends on a concrete
workflow controller.
:param env: A set of environment variables to overwrite.
:return: List of workflow commands.
"""
# Add all tasks in IDLE state.
@@ -212,11 +204,6 @@ class WorkflowController(object):
states.IDLE
)
# TODO(rakhmerov): We should not be updating any DB objects in a WF
# controller.
for task_ex in idle_tasks:
self._update_task_ex_env(task_ex, env)
return [
commands.RunExistingTask(self.wf_ex, self.wf_spec, t)
for t in idle_tasks