/usr/lib/python2.7/dist-packages/taskflow/engines/action_engine/deciders.py is in python-taskflow 2.3.0-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 | # -*- coding: utf-8 -*-
# Copyright (C) 2015 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 abc
import itertools
import six
from taskflow import deciders
from taskflow.engines.action_engine import compiler
from taskflow.engines.action_engine import traversal
from taskflow import states
@six.add_metaclass(abc.ABCMeta)
class Decider(object):
"""Base class for deciders.
Provides interface to be implemented by sub-classes.
Deciders check whether next atom in flow should be executed or not.
"""
@abc.abstractmethod
def tally(self, runtime):
"""Tally edge deciders on whether this decider should allow running.
The returned value is a list of edge deciders that voted
'nay' (do not allow running).
"""
@abc.abstractmethod
def affect(self, runtime, nay_voters):
"""Affects associated atoms due to at least one 'nay' edge decider.
This will alter the associated atom + some set of successor atoms by
setting there state and intention to ``IGNORE`` so that they are
ignored in future runtime activities.
"""
def check_and_affect(self, runtime):
"""Handles :py:func:`~.tally` + :py:func:`~.affect` in right order.
NOTE(harlowja): If there are zero 'nay' edge deciders then it is
assumed this decider should allow running.
Returns boolean of whether this decider allows for running (or not).
"""
nay_voters = self.tally(runtime)
if nay_voters:
self.affect(runtime, nay_voters)
return False
return True
def _affect_all_successors(atom, runtime):
execution_graph = runtime.compilation.execution_graph
successors_iter = traversal.depth_first_iterate(
execution_graph, atom, traversal.Direction.FORWARD)
runtime.reset_atoms(itertools.chain([atom], successors_iter),
state=states.IGNORE, intention=states.IGNORE)
def _affect_successor_tasks_in_same_flow(atom, runtime):
execution_graph = runtime.compilation.execution_graph
successors_iter = traversal.depth_first_iterate(
execution_graph, atom, traversal.Direction.FORWARD,
# Do not go through nested flows but do follow *all* tasks that
# are directly connected in this same flow (thus the reason this is
# called the same flow decider); retries are direct successors
# of flows, so they should also be not traversed through, but
# setting this explicitly ensures that.
through_flows=False, through_retries=False)
runtime.reset_atoms(itertools.chain([atom], successors_iter),
state=states.IGNORE, intention=states.IGNORE)
def _affect_atom(atom, runtime):
runtime.reset_atoms([atom], state=states.IGNORE, intention=states.IGNORE)
def _affect_direct_task_neighbors(atom, runtime):
def _walk_neighbors():
execution_graph = runtime.compilation.execution_graph
for node in execution_graph.successors_iter(atom):
node_data = execution_graph.node[node]
if node_data['kind'] == compiler.TASK:
yield node
successors_iter = _walk_neighbors()
runtime.reset_atoms(itertools.chain([atom], successors_iter),
state=states.IGNORE, intention=states.IGNORE)
class IgnoreDecider(Decider):
"""Checks any provided edge-deciders and determines if ok to run."""
_depth_strategies = {
deciders.Depth.ALL: _affect_all_successors,
deciders.Depth.ATOM: _affect_atom,
deciders.Depth.FLOW: _affect_successor_tasks_in_same_flow,
deciders.Depth.NEIGHBORS: _affect_direct_task_neighbors,
}
def __init__(self, atom, edge_deciders):
self._atom = atom
self._edge_deciders = edge_deciders
def tally(self, runtime):
if not self._edge_deciders:
return []
# Gather all atoms (the ones that were not ignored) results so that
# those results can be used
# by the decider(s) that are making a decision as to pass or
# not pass...
states_intentions = runtime.storage.get_atoms_states(
ed.from_node.name for ed in self._edge_deciders
if ed.kind in compiler.ATOMS)
history = {}
for atom_name in six.iterkeys(states_intentions):
atom_state, _atom_intention = states_intentions[atom_name]
if atom_state != states.IGNORE:
history[atom_name] = runtime.storage.get(atom_name)
nay_voters = []
for ed in self._edge_deciders:
if (ed.kind in compiler.ATOMS and
# It was an ignored atom (not included in history and the
# only way that is possible is via above loop skipping
# it...)
ed.from_node.name not in history):
continue
if not ed.decider(history=history):
nay_voters.append(ed)
return nay_voters
def affect(self, runtime, nay_voters):
# If there were many 'nay' edge deciders that were targeted
# at this atom, then we need to pick the one which has the widest
# impact and respect that one as the decider depth that will
# actually affect things.
widest_depth = deciders.pick_widest(ed.depth for ed in nay_voters)
affector = self._depth_strategies[widest_depth]
return affector(self._atom, runtime)
class NoOpDecider(Decider):
"""No-op decider that says it is always ok to run & has no effect(s)."""
def tally(self, runtime):
"""Always good to go."""
return []
def affect(self, runtime, nay_voters):
"""Does nothing."""
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