270 lines
8.7 KiB
Python
270 lines
8.7 KiB
Python
#
|
|
# 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 itertools
|
|
|
|
from oslo_utils import encodeutils
|
|
import six
|
|
|
|
from heat.common import exception
|
|
from heat.common.i18n import _
|
|
|
|
|
|
class CircularDependencyException(exception.HeatException):
|
|
msg_fmt = _("Circular Dependency Found: %(cycle)s")
|
|
|
|
|
|
class Node(object):
|
|
'''A node in a dependency graph.'''
|
|
|
|
def __init__(self, requires=None, required_by=None):
|
|
'''
|
|
Initialise the node, optionally with a set of keys this node
|
|
requires and/or a set of keys that this node is required by.
|
|
'''
|
|
self.require = requires and requires.copy() or set()
|
|
self.satisfy = required_by and required_by.copy() or set()
|
|
|
|
def copy(self):
|
|
'''Return a copy of the node.'''
|
|
return Node(self.require, self.satisfy)
|
|
|
|
def reverse_copy(self):
|
|
'''Return a copy of the node with the edge directions reversed.'''
|
|
return Node(self.satisfy, self.require)
|
|
|
|
def required_by(self, source=None):
|
|
'''
|
|
List the keys that require this node, and optionally add a
|
|
new one.
|
|
'''
|
|
if source is not None:
|
|
self.satisfy.add(source)
|
|
return iter(self.satisfy)
|
|
|
|
def requires(self, target):
|
|
'''Add a key that this node requires.'''
|
|
self.require.add(target)
|
|
|
|
def __isub__(self, target):
|
|
'''Remove a key that this node requires.'''
|
|
self.require.remove(target)
|
|
return self
|
|
|
|
def __nonzero__(self):
|
|
'''Return True if this node is not a leaf (it requires other nodes).'''
|
|
return bool(self.require)
|
|
|
|
def stem(self):
|
|
'''Return True if this node is a stem (required by nothing).'''
|
|
return not bool(self.satisfy)
|
|
|
|
def disjoint(self):
|
|
'''Return True if this node is both a leaf and a stem.'''
|
|
return (not self) and self.stem()
|
|
|
|
def __len__(self):
|
|
'''Count the number of keys required by this node.'''
|
|
return len(self.require)
|
|
|
|
def __iter__(self):
|
|
'''Iterate over the keys required by this node.'''
|
|
return iter(self.require)
|
|
|
|
def __str__(self):
|
|
'''Return a human-readable string representation of the node.'''
|
|
text = '{%s}' % ', '.join(str(n) for n in self)
|
|
return encodeutils.safe_encode(text)
|
|
|
|
def __unicode__(self):
|
|
'''Return a human-readable string representation of the node.'''
|
|
text = '{%s}' % ', '.join(six.text_type(n) for n in self)
|
|
return encodeutils.safe_decode(text)
|
|
|
|
def __repr__(self):
|
|
'''Return a string representation of the node.'''
|
|
return repr(self.require)
|
|
|
|
|
|
class Graph(collections.defaultdict):
|
|
'''A mutable mapping of objects to nodes in a dependency graph.'''
|
|
|
|
def __init__(self, *args):
|
|
super(Graph, self).__init__(Node, *args)
|
|
|
|
def map(self, func):
|
|
'''
|
|
Return a dictionary derived from mapping the supplied function onto
|
|
each node in the graph.
|
|
'''
|
|
return dict((k, func(n)) for k, n in self.items())
|
|
|
|
def copy(self):
|
|
'''Return a copy of the graph.'''
|
|
return Graph(self.map(lambda n: n.copy()))
|
|
|
|
def reverse_copy(self):
|
|
'''Return a copy of the graph with the edges reversed.'''
|
|
return Graph(self.map(lambda n: n.reverse_copy()))
|
|
|
|
def edges(self):
|
|
'''Return an iterator over all of the edges in the graph.'''
|
|
def outgoing_edges(rqr, node):
|
|
if node.disjoint():
|
|
yield (rqr, None)
|
|
else:
|
|
for rqd in node:
|
|
yield (rqr, rqd)
|
|
return itertools.chain.from_iterable(outgoing_edges(*i)
|
|
for i in six.iteritems(self))
|
|
|
|
def __delitem__(self, key):
|
|
'''Delete the node given by the specified key from the graph.'''
|
|
node = self[key]
|
|
|
|
for src in node.required_by():
|
|
src_node = self[src]
|
|
if key in src_node:
|
|
src_node -= key
|
|
|
|
return super(Graph, self).__delitem__(key)
|
|
|
|
def __str__(self):
|
|
'''Convert the graph to a human-readable string.'''
|
|
pairs = ('%s: %s' % (str(k), str(v)) for k, v in six.iteritems(self))
|
|
text = '{%s}' % ', '.join(pairs)
|
|
return encodeutils.safe_encode(text)
|
|
|
|
def __unicode__(self):
|
|
'''Convert the graph to a human-readable string.'''
|
|
pairs = ('%s: %s' % (six.text_type(k), six.text_type(v))
|
|
for k, v in six.iteritems(self))
|
|
text = '{%s}' % ', '.join(pairs)
|
|
return encodeutils.safe_decode(text)
|
|
|
|
@staticmethod
|
|
def toposort(graph):
|
|
'''
|
|
Return a topologically sorted iterator over a dependency graph.
|
|
|
|
This is a destructive operation for the graph.
|
|
'''
|
|
for iteration in six.moves.xrange(len(graph)):
|
|
for key, node in six.iteritems(graph):
|
|
if not node:
|
|
yield key
|
|
del graph[key]
|
|
break
|
|
else:
|
|
# There are nodes remaining, but none without
|
|
# dependencies: a cycle
|
|
raise CircularDependencyException(cycle=six.text_type(graph))
|
|
|
|
|
|
class Dependencies(object):
|
|
'''Helper class for calculating a dependency graph.'''
|
|
|
|
def __init__(self, edges=None):
|
|
'''
|
|
Initialise, optionally with a list of edges, in the form of
|
|
(requirer, required) tuples.
|
|
'''
|
|
edges = edges or []
|
|
self._graph = Graph()
|
|
for e in edges:
|
|
self += e
|
|
|
|
def __iadd__(self, edge):
|
|
'''Add another edge, in the form of a (requirer, required) tuple.'''
|
|
requirer, required = edge
|
|
|
|
if required is None:
|
|
# Just ensure the node is created by accessing the defaultdict
|
|
self._graph[requirer]
|
|
else:
|
|
self._graph[required].required_by(requirer)
|
|
self._graph[requirer].requires(required)
|
|
|
|
return self
|
|
|
|
def required_by(self, last):
|
|
'''
|
|
List the keys that require the specified node.
|
|
'''
|
|
if last not in self._graph:
|
|
raise KeyError
|
|
|
|
return self._graph[last].required_by()
|
|
|
|
def __getitem__(self, last):
|
|
'''
|
|
Return a partial dependency graph consisting of the specified node and
|
|
all those that require it only.
|
|
'''
|
|
if last not in self._graph:
|
|
raise KeyError
|
|
|
|
def get_edges(key):
|
|
def requirer_edges(rqr):
|
|
# Concatenate the dependency on the current node with the
|
|
# recursive generated list
|
|
return itertools.chain([(rqr, key)], get_edges(rqr))
|
|
|
|
# Get the edge list for each node that requires the current node
|
|
edge_lists = six.moves.map(requirer_edges,
|
|
self._graph[key].required_by())
|
|
# Combine the lists into one long list
|
|
return itertools.chain.from_iterable(edge_lists)
|
|
|
|
if self._graph[last].stem():
|
|
# Nothing requires this, so just add the node itself
|
|
edges = [(last, None)]
|
|
else:
|
|
edges = get_edges(last)
|
|
|
|
return Dependencies(edges)
|
|
|
|
def __str__(self):
|
|
'''
|
|
Return a human-readable string representation of the dependency graph
|
|
'''
|
|
return str(self._graph)
|
|
|
|
def __unicode__(self):
|
|
'''
|
|
Return a human-readable string representation of the dependency graph
|
|
'''
|
|
return six.text_type(self._graph)
|
|
|
|
def __repr__(self):
|
|
'''Return a string representation of the object.'''
|
|
edge_reprs = (repr(e) for e in self._graph.edges())
|
|
text = 'Dependencies([%s])' % ', '.join(edge_reprs)
|
|
return encodeutils.safe_encode(text)
|
|
|
|
def graph(self, reverse=False):
|
|
'''Return a copy of the underlying dependency graph.'''
|
|
if reverse:
|
|
return self._graph.reverse_copy()
|
|
else:
|
|
return self._graph.copy()
|
|
|
|
def __iter__(self):
|
|
'''Return a topologically sorted iterator.'''
|
|
return Graph.toposort(self.graph())
|
|
|
|
def __reversed__(self):
|
|
'''Return a reverse topologically sorted iterator.'''
|
|
return Graph.toposort(self.graph(reverse=True))
|