1f7edf2316
Since the node set may have been altered since the last connect we want to make sure clear out the edges and the providers of items before connecting. Change-Id: I73e6b3bc5d83a82d2b13dbb6b06c66e794d66e9c
139 lines
5.3 KiB
Python
139 lines
5.3 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# vim: tabstop=4 shiftwidth=4 softtabstop=4
|
|
|
|
# Copyright (C) 2012 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 collections
|
|
import logging
|
|
|
|
from networkx.algorithms import dag
|
|
from networkx.classes import digraph
|
|
from networkx import exception as g_exc
|
|
|
|
from taskflow import decorators
|
|
from taskflow import exceptions as exc
|
|
from taskflow.patterns import linear_flow
|
|
from taskflow import utils
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
class Flow(linear_flow.Flow):
|
|
"""A extension of the linear flow which will run the associated tasks in
|
|
a linear topological ordering (and reverse using the same linear
|
|
topological order)"""
|
|
|
|
def __init__(self, name, parents=None):
|
|
super(Flow, self).__init__(name, parents)
|
|
self._graph = digraph.DiGraph()
|
|
|
|
@decorators.locked
|
|
def add(self, task):
|
|
# Only insert the node to start, connect all the edges
|
|
# together later after all nodes have been added since if we try
|
|
# to infer the edges at this stage we likely will fail finding
|
|
# dependencies from nodes that don't exist.
|
|
assert isinstance(task, collections.Callable)
|
|
r = utils.Runner(task)
|
|
self._graph.add_node(r, uuid=r.uuid)
|
|
self._runners = []
|
|
return r.uuid
|
|
|
|
def _add_dependency(self, provider, requirer):
|
|
if not self._graph.has_edge(provider, requirer):
|
|
self._graph.add_edge(provider, requirer)
|
|
|
|
def __str__(self):
|
|
lines = ["GraphFlow: %s" % (self.name)]
|
|
lines.append(" Number of tasks: %s" % (self._graph.number_of_nodes()))
|
|
lines.append(" Number of dependencies: %s"
|
|
% (self._graph.number_of_edges()))
|
|
lines.append(" State: %s" % (self.state))
|
|
return "\n".join(lines)
|
|
|
|
@decorators.locked
|
|
def remove(self, task_uuid):
|
|
remove_nodes = []
|
|
for r in self._graph.nodes_iter():
|
|
if r.uuid == task_uuid:
|
|
remove_nodes.append(r)
|
|
if not remove_nodes:
|
|
raise IndexError("No task found with uuid %s" % (task_uuid))
|
|
else:
|
|
for r in remove_nodes:
|
|
self._graph.remove_node(r)
|
|
self._runners = []
|
|
|
|
def _ordering(self):
|
|
try:
|
|
return self._connect()
|
|
except g_exc.NetworkXUnfeasible:
|
|
raise exc.InvalidStateException("Unable to correctly determine "
|
|
"the path through the provided "
|
|
"flow which will satisfy the "
|
|
"tasks needed inputs and outputs.")
|
|
|
|
def _connect(self):
|
|
"""Connects the nodes & edges of the graph together by examining who
|
|
the requirements of each node and finding another node that will
|
|
create said dependency."""
|
|
if len(self._graph) == 0:
|
|
return []
|
|
if self._runners:
|
|
return self._runners
|
|
|
|
# Clear out all edges (since we want to do a fresh connection)
|
|
for (u, v) in self._graph.edges():
|
|
self._graph.remove_edge(u, v)
|
|
|
|
# Link providers to requirers.
|
|
#
|
|
# TODO(harlowja): allow for developers to manually establish these
|
|
# connections instead of automatically doing it for them??
|
|
for n in self._graph.nodes_iter():
|
|
n_providers = {}
|
|
n_requires = set(utils.get_attr(n.task, 'requires', []))
|
|
if n_requires:
|
|
LOG.debug("Finding providers of %s for %s", n_requires, n)
|
|
for p in self._graph.nodes_iter():
|
|
if n is p:
|
|
continue
|
|
p_provides = set(utils.get_attr(p.task, 'provides', []))
|
|
p_satisfies = n_requires & p_provides
|
|
if p_satisfies:
|
|
# P produces for N so thats why we link P->N
|
|
# and not N->P
|
|
self._add_dependency(p, n)
|
|
for k in p_satisfies:
|
|
n_providers[k] = p
|
|
LOG.debug("Found provider of %s from %s",
|
|
p_satisfies, p)
|
|
n_requires = n_requires - p_satisfies
|
|
if n_requires:
|
|
raise exc.MissingDependencies(n, sorted(n_requires))
|
|
n.providers = n_providers
|
|
|
|
# Now figure out the order so that we can give the runners there
|
|
# optional item providers as well as figure out the topological run
|
|
# order.
|
|
run_order = dag.topological_sort(self._graph)
|
|
run_stack = []
|
|
for r in run_order:
|
|
r.runs_before = list(reversed(run_stack))
|
|
run_stack.append(r)
|
|
self._runners = run_order
|
|
return run_order
|