Files
deb-python-taskflow/taskflow/engines/action_engine/graph_analyzer.py
Anastasia Karpinska 9632fe6392 Graph action refactoring
* get rid of dependency counter in graph action:
  analyze graph directly instead when we need to determine nodes we
  need to execute or revert next;
* move graph interpreting to separate class, GraphAnalyzer:
  instead of inheriting this code from base graph action we now use
  composition;
* get rid of direct dependency of graph action on engine.

Relates to blueprint smart-revert
Co-authored-by: Ivan A. Melnikov <imelnikov@griddynamics.com>
Change-Id: Ib6499d2f2d5b568d7f2a45af3c5ed6d8d9ace39b
2013-12-26 16:26:55 +02:00

94 lines
3.0 KiB
Python

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import six
from taskflow import states as st
class GraphAnalyzer(object):
"""Analyzes graph to get next nodes for execution or reversion"""
def __init__(self, graph, storage):
self._graph = graph
self._storage = storage
@property
def graph(self):
return self._graph
def browse_nodes_for_execute(self, node=None):
"""Browse next nodes to execute for given node if
specified and for whole graph otherwise.
"""
if node:
nodes = self._graph.successors(node)
else:
nodes = self._graph.nodes_iter()
available_nodes = []
for node in nodes:
if self._is_ready_for_execute(node):
available_nodes.append(node)
return available_nodes
def browse_nodes_for_revert(self, node=None):
"""Browse next nodes to revert for given node if
specified and for whole graph otherwise.
"""
if node:
nodes = self._graph.predecessors(node)
else:
nodes = self._graph.nodes_iter()
available_nodes = []
for node in nodes:
if self._is_ready_for_revert(node):
available_nodes.append(node)
return available_nodes
def _is_ready_for_execute(self, task):
"""Checks if task is ready to be executed"""
state = self._storage.get_task_state(task.name)
if not st.check_task_transition(state, st.RUNNING):
return False
task_names = []
for prev_task in self._graph.predecessors(task):
task_names.append(prev_task.name)
task_states = self._storage.get_tasks_states(task_names)
return all(state == st.SUCCESS
for state in six.itervalues(task_states))
def _is_ready_for_revert(self, task):
"""Checks if task is ready to be reverted"""
state = self._storage.get_task_state(task.name)
if not st.check_task_transition(state, st.REVERTING):
return False
task_names = []
for prev_task in self._graph.successors(task):
task_names.append(prev_task.name)
task_states = self._storage.get_tasks_states(task_names)
return all(state in (st.PENDING, st.REVERTED)
for state in six.itervalues(task_states))