/usr/lib/python2.7/dist-packages/taskflow/flow.py is in python-taskflow 2.3.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | # -*- coding: utf-8 -*-
# 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 abc
from oslo_utils import reflection
import six
# Link metadata keys that have inherent/special meaning.
#
# This key denotes the link is an invariant that ensures the order is
# correctly preserved.
LINK_INVARIANT = 'invariant'
# This key denotes the link is a manually/user-specified.
LINK_MANUAL = 'manual'
# This key denotes the link was created when resolving/compiling retries.
LINK_RETRY = 'retry'
# This key denotes the link was created due to symbol constraints and the
# value will be a set of names that the constraint ensures are satisfied.
LINK_REASONS = 'reasons'
#
# This key denotes a callable that will determine if the target is visited.
LINK_DECIDER = 'decider'
# Chop off full module names of patterns that are built-in to taskflow...
_CHOP_PAT = "taskflow.patterns."
_CHOP_PAT_LEN = len(_CHOP_PAT)
# This key denotes the depth the decider will apply (defaulting to all).
LINK_DECIDER_DEPTH = 'decider_depth'
@six.add_metaclass(abc.ABCMeta)
class Flow(object):
"""The base abstract class of all flow implementations.
A flow is a structure that defines relationships between tasks. You can
add tasks and other flows (as subflows) to the flow, and the flow provides
a way to implicitly or explicitly define how they are interdependent.
Exact structure of the relationships is defined by concrete
implementation, while this class defines common interface and adds
human-readable (not necessary unique) name.
NOTE(harlowja): if a flow is placed in another flow as a subflow, a desired
way to compose flows together, then it is valid and permissible that during
compilation the subflow & parent flow *may* be flattened into a new flow.
"""
def __init__(self, name, retry=None):
self._name = six.text_type(name)
self._retry = retry
# NOTE(akarpinska): if retry doesn't have a name,
# the name of its owner will be assigned
if self._retry is not None and self._retry.name is None:
self._retry.name = self.name + "_retry"
@property
def name(self):
"""A non-unique name for this flow (human readable)."""
return self._name
@property
def retry(self):
"""The associated flow retry controller.
This retry controller object will affect & control how (and if) this
flow and its contained components retry when execution is underway and
a failure occurs.
"""
return self._retry
@abc.abstractmethod
def add(self, *items):
"""Adds a given item/items to this flow."""
@abc.abstractmethod
def __len__(self):
"""Returns how many items are in this flow."""
@abc.abstractmethod
def __iter__(self):
"""Iterates over the children of the flow."""
@abc.abstractmethod
def iter_links(self):
"""Iterates over dependency links between children of the flow.
Iterates over 3-tuples ``(A, B, meta)``, where
* ``A`` is a child (atom or subflow) link starts from;
* ``B`` is a child (atom or subflow) link points to; it is
said that ``B`` depends on ``A`` or ``B`` requires ``A``;
* ``meta`` is link metadata, a dictionary.
"""
@abc.abstractmethod
def iter_nodes(self):
"""Iterate over nodes of the flow.
Iterates over 2-tuples ``(A, meta)``, where
* ``A`` is a child (atom or subflow) of current flow;
* ``meta`` is link metadata, a dictionary.
"""
def __str__(self):
cls_name = reflection.get_class_name(self)
if cls_name.startswith(_CHOP_PAT):
cls_name = cls_name[_CHOP_PAT_LEN:]
return "%s: %s(len=%d)" % (cls_name, self.name, len(self))
@property
def provides(self):
"""Set of symbol names provided by the flow."""
provides = set()
if self._retry is not None:
provides.update(self._retry.provides)
for item in self:
provides.update(item.provides)
return frozenset(provides)
@abc.abstractproperty
def requires(self):
"""Set of *unsatisfied* symbol names required by the flow."""
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