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remove most of the resolver boilerplate, keep the interesting functions

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Signed-off-by: Nico Schottelius <nico@brief.schottelius.org>
This commit is contained in:
Nico Schottelius 2012-12-14 08:43:52 +01:00
commit 6a8778e595
1 changed files with 17 additions and 104 deletions
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121
cdist/core/cdist_object.py
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@ -213,78 +213,6 @@ class CdistObject(object):
def satisfied_requirements(self):
# -*- coding: utf-8 -*-
#
# 2011 Steven Armstrong (steven-cdist at armstrong.cc)
#
# This file is part of cdist.
#
# cdist is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cdist is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cdist. If not, see <http://www.gnu.org/licenses/>.
#
#
import logging
import os
import itertools
import fnmatch
import cdist
log = logging.getLogger(__name__)
class CircularReferenceError(cdist.Error):
def __init__(self, cdist_object, required_object):
self.cdist_object = cdist_object
self.required_object = required_object
def __str__(self):
return 'Circular reference detected: %s -> %s' % (self.cdist_object.name, self.required_object.name)
class RequirementNotFoundError(cdist.Error):
def __init__(self, requirement):
self.requirement = requirement
def __str__(self):
return 'Requirement could not be found: %s' % self.requirement
class DependencyResolver(object):
"""Cdist's dependency resolver.
Usage:
>> resolver = DependencyResolver(list_of_objects)
# Easy access to the objects we are working with
>> resolver.objects['__some_type/object_id']
<CdistObject __some_type/object_id>
# Easy access to a specific objects dependencies
>> resolver.dependencies['__some_type/object_id']
[<CdistObject __other_type/dependency>, <CdistObject __some_type/object_id>]
# Pretty print the dependency graph
>> from pprint import pprint
>> pprint(resolver.dependencies)
# Iterate over all existing objects in the correct order
>> for cdist_object in resolver:
>> do_something_with(cdist_object)
"""
def __init__(self, objects, logger=None):
self.objects = dict((o.name, o) for o in objects)
self._dependencies = None
self.log = logger or log
@property
def dependencies(self):
"""Build the dependency graph.
@ -348,37 +276,22 @@ class DependencyResolver(object):
# preprocessed again if someone would call us multiple times.
cdist_object.autorequire = []
def _resolve_object_dependencies(self, cdist_object, resolved, unresolved):
"""Resolve all dependencies for the given cdist_object and store them
in the list which is passed as the 'resolved' arguments.
e.g.
resolved = []
unresolved = []
resolve_object_dependencies(some_object, resolved, unresolved)
print("Dependencies for %s: %s" % (some_object, resolved))
"""
self.log.debug('Resolving dependencies for: %s' % cdist_object.name)
try:
unresolved.append(cdist_object)
for required_object in self.find_requirements_by_name(cdist_object.requirements):
self.log.debug("Object %s requires %s", cdist_object, required_object)
if required_object not in resolved:
if required_object in unresolved:
raise CircularReferenceError(cdist_object, required_object)
self._resolve_object_dependencies(required_object, resolved, unresolved)
resolved.append(cdist_object)
unresolved.remove(cdist_object)
except RequirementNotFoundError as e:
raise cdist.CdistObjectError(cdist_object, "requires non-existing " + e.requirement)
class CircularReferenceError(cdist.Error):
def __init__(self, cdist_object, required_object):
self.cdist_object = cdist_object
self.required_object = required_object
def __str__(self):
return 'Circular reference detected: %s -> %s' % (self.cdist_object.name, self.required_object.name)
class RequirementNotFoundError(cdist.Error):
def __init__(self, requirement):
self.requirement = requirement
def __str__(self):
return 'Requirement could not be found: %s' % self.requirement
def __iter__(self):
"""Iterate over all unique objects and yield them in the correct order.
"""
iterable = itertools.chain(*self.dependencies.values())
# Keep record of objects that have already been seen
seen = set()
seen_add = seen.add
for cdist_object in itertools.filterfalse(seen.__contains__, iterable):
seen_add(cdist_object)
yield cdist_object