cdist/cdist/core/cdist_object.py
Nico Schottelius 6a8778e595 remove most of the resolver boilerplate, keep the interesting functions
Signed-off-by: Nico Schottelius <nico@brief.schottelius.org>
2012-12-14 08:43:52 +01:00

297 lines
12 KiB
Python

# -*- coding: utf-8 -*-
#
# 2011 Steven Armstrong (steven-cdist at armstrong.cc)
# 2011-2012 Nico Schottelius (nico-cdist at schottelius.org)
#
# 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 collections
import cdist
import cdist.core
from cdist.util import fsproperty
log = logging.getLogger(__name__)
OBJECT_MARKER = '.cdist'
class IllegalObjectIdError(cdist.Error):
def __init__(self, object_id, message=None):
self.object_id = object_id
self.message = message or 'Illegal object id'
def __str__(self):
return '%s: %s' % (self.message, self.object_id)
class CdistObject(object):
"""Represents a cdist object.
All interaction with objects in cdist should be done through this class.
Directly accessing an object through the file system from python code is
a bug.
"""
# Constants for use with Object.state
STATE_PREPARED = "prepared"
STATE_RUNNING = "running"
STATE_DONE = "done"
@classmethod
def list_objects(cls, object_base_path, type_base_path):
"""Return a list of object instances"""
for object_name in cls.list_object_names(object_base_path):
type_name, object_id = cls.split_name(object_name)
yield cls(cdist.core.CdistType(type_base_path, type_name), object_base_path, object_id=object_id)
@classmethod
def list_type_names(cls, object_base_path):
"""Return a list of type names"""
return os.listdir(object_base_path)
@classmethod
def list_object_names(cls, object_base_path):
"""Return a list of object names"""
for path, dirs, files in os.walk(object_base_path):
if OBJECT_MARKER in dirs:
yield os.path.relpath(path, object_base_path)
@staticmethod
def split_name(object_name):
"""split_name('__type_name/the/object_id') -> ('__type_name', 'the/object_id')
Split the given object name into it's type and object_id parts.
"""
type_name = object_name.split(os.sep)[0]
# FIXME: allow object without object_id? e.g. for singleton
object_id = os.sep.join(object_name.split(os.sep)[1:])
return type_name, object_id
@staticmethod
def join_name(type_name, object_id):
"""join_name('__type_name', 'the/object_id') -> __type_name/the/object_id'
Join the given type_name and object_id into an object name.
"""
return os.path.join(type_name, object_id)
def validate_object_id(self):
# FIXME: also check that there is no object ID when type is singleton?
"""Validate the given object_id and raise IllegalObjectIdError if it's not valid.
"""
if self.object_id:
if OBJECT_MARKER in self.object_id.split(os.sep):
raise IllegalObjectIdError(self.object_id, 'object_id may not contain \'%s\'' % OBJECT_MARKER)
if '//' in self.object_id:
raise IllegalObjectIdError(self.object_id, 'object_id may not contain //')
# If no object_id and type is not singleton => error out
if not self.object_id and not self.cdist_type.is_singleton:
raise IllegalObjectIdError(self.object_id,
"Missing object_id and type is not a singleton.")
def __init__(self, cdist_type, base_path, object_id=None):
self.cdist_type = cdist_type # instance of Type
self.base_path = base_path
self.object_id = object_id
self.validate_object_id()
self.sanitise_object_id()
self.name = self.join_name(self.cdist_type.name, self.object_id)
self.path = os.path.join(self.cdist_type.path, self.object_id, OBJECT_MARKER)
self.absolute_path = os.path.join(self.base_path, self.path)
self.code_local_path = os.path.join(self.path, "code-local")
self.code_remote_path = os.path.join(self.path, "code-remote")
self.parameter_path = os.path.join(self.path, "parameter")
def object_from_name(self, object_name):
"""Convenience method for creating an object instance from an object name.
Mainly intended to create objects when resolving requirements.
e.g:
<CdistObject __foo/bar>.object_from_name('__other/object') -> <CdistObject __other/object>
"""
base_path = self.base_path
type_path = self.cdist_type.base_path
type_name, object_id = self.split_name(object_name)
cdist_type = self.cdist_type.__class__(type_path, type_name)
return self.__class__(cdist_type, base_path, object_id=object_id)
def __repr__(self):
return '<CdistObject %s>' % self.name
def __eq__(self, other):
"""define equality as 'name is the same'"""
return self.name == other.name
def __hash__(self):
return hash(self.name)
def __lt__(self, other):
return isinstance(other, self.__class__) and self.name < other.name
def sanitise_object_id(self):
"""
Remove leading and trailing slash (one only)
"""
# Allow empty object id for singletons
if self.object_id:
# Remove leading slash
if self.object_id[0] == '/':
self.object_id = self.object_id[1:]
# Remove trailing slash
if self.object_id[-1] == '/':
self.object_id = self.object_id[:-1]
# FIXME: still needed?
@property
def explorer_path(self):
"""Create and return the relative path to this objects explorers"""
# create absolute path
path = os.path.join(self.absolute_path, "explorer")
if not os.path.isdir(path):
os.mkdir(path)
# return relative path
return os.path.join(self.path, "explorer")
requirements = fsproperty.FileListProperty(lambda obj: os.path.join(obj.absolute_path, 'require'))
autorequire = fsproperty.FileListProperty(lambda obj: os.path.join(obj.absolute_path, 'autorequire'))
parameters = fsproperty.DirectoryDictProperty(lambda obj: os.path.join(obj.base_path, obj.parameter_path))
explorers = fsproperty.DirectoryDictProperty(lambda obj: os.path.join(obj.base_path, obj.explorer_path))
changed = fsproperty.FileBooleanProperty(lambda obj: os.path.join(obj.absolute_path, "changed"))
state = fsproperty.FileStringProperty(lambda obj: os.path.join(obj.absolute_path, "state"))
source = fsproperty.FileListProperty(lambda obj: os.path.join(obj.absolute_path, "source"))
code_local = fsproperty.FileStringProperty(lambda obj: os.path.join(obj.base_path, obj.code_local_path))
code_remote = fsproperty.FileStringProperty(lambda obj: os.path.join(obj.base_path, obj.code_remote_path))
@property
def exists(self):
"""Checks wether this cdist object exists on the file systems."""
return os.path.exists(self.absolute_path)
def create(self):
"""Create this cdist object on the filesystem.
"""
try:
os.makedirs(self.absolute_path, exist_ok=False)
absolute_parameter_path = os.path.join(self.base_path, self.parameter_path)
os.makedirs(absolute_parameter_path, exist_ok=False)
except EnvironmentError as error:
raise cdist.Error('Error creating directories for cdist object: %s: %s' % (self, error))
def satisfied_requirements(self):
@property
def dependencies(self):
"""Build the dependency graph.
Returns a dict where the keys are the object names and the values are
lists of all dependencies including the key object itself.
"""
if self._dependencies is None:
log.info("Resolving dependencies...")
self._dependencies = d = {}
self._preprocess_requirements()
for name,cdist_object in self.objects.items():
resolved = []
unresolved = []
self._resolve_object_dependencies(cdist_object, resolved, unresolved)
d[name] = resolved
return self._dependencies
def find_requirements_by_name(self, requirements):
"""Takes a list of requirement patterns and returns a list of matching object instances.
Patterns are expected to be Unix shell-style wildcards for use with fnmatch.filter.
find_requirements_by_name(['__type/object_id', '__other_type/*']) ->
[<Object __type/object_id>, <Object __other_type/any>, <Object __other_type/match>]
"""
object_names = self.objects.keys()
for pattern in requirements:
found = False
for requirement in fnmatch.filter(object_names, pattern):
found = True
yield self.objects[requirement]
if not found:
# FIXME: get rid of the singleton object_id, it should be invisible to the code -> hide it in Object
singleton = os.path.join(pattern, 'singleton')
if singleton in self.objects:
yield self.objects[singleton]
else:
raise RequirementNotFoundError(pattern)
def _preprocess_requirements(self):
"""Find all autorequire dependencies and merge them to be just requirements
for further processing.
"""
for cdist_object in self.objects.values():
if cdist_object.autorequire:
# The objects (children) that this cdist_object (parent) defined
# in it's type manifest shall inherit all explicit requirements
# that the parent has so that user defined requirements are
# fullfilled and processed in the expected order.
for auto_requirement in self.find_requirements_by_name(cdist_object.autorequire):
for requirement in cdist_object.requirements:
if requirement not in auto_requirement.requirements:
auto_requirement.requirements.append(requirement)
# On the other hand the parent shall depend on all the children
# it created so that the user can setup dependencies on it as a
# whole without having to know anything about the parents
# internals.
cdist_object.requirements.extend(cdist_object.autorequire)
# As we changed the object on disc, we have to ensure it is not
# preprocessed again if someone would call us multiple times.
cdist_object.autorequire = []
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