349 lines
11 KiB
Python
349 lines
11 KiB
Python
# Copyright 2013 Hewlett-Packard Development Company, L.P.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from __future__ import print_function
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import argparse
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import collections
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import errno
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import logging
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import os
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import sys
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import yaml
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import diskimage_builder.logging_config
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logger = logging.getLogger(__name__)
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class MissingElementException(Exception):
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pass
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class AlreadyProvidedException(Exception):
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pass
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class MissingOSException(Exception):
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pass
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class InvalidElementDir(Exception):
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pass
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class Element(object):
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"""An element"""
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def _get_element_set(self, path):
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"""Get element set from element-[deps|provides] file
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Arguments:
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:param path: path to element description
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:return: the set of elements in the file, or a blank set if
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the file is not found.
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"""
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try:
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with open(path) as f:
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lines = (line.strip() for line in f)
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# Strip blanks, but do we want to strip comment lines
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# too? No use case at the moment, and comments might
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# break other things that poke at the element-* files.
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lines = (line for line in lines if line)
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return set(lines)
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except IOError as e:
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if e.errno == errno.ENOENT:
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return set([])
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else:
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raise
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def _make_rdeps(self, all_elements):
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"""Make a list of reverse dependencies (who depends on us).
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Only valid after _find_all_elements()
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Arguments:
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:param all_elements: dict as returned by _find_all_elements()
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:return: nothing, but elements will have r_depends var
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"""
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# note; deliberatly left out of __init__ so that accidental
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# access without init raises error
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self.r_depends = []
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for name, element in all_elements.items():
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if self.name in element.depends:
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self.r_depends.append(element.name)
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def __init__(self, name, path):
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"""A new element
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:param name: The element name
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:param path: Full path to element. element-deps and
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element-provides files will be parsed
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"""
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self.name = name
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self.path = path
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# read the provides & depends files for this element into a
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# set; if the element has them.
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self.provides = self._get_element_set(
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os.path.join(path, 'element-provides'))
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self.depends = self._get_element_set(
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os.path.join(path, 'element-deps'))
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logger.debug("New element : %s", str(self))
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def __eq__(self, other):
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return self.name == other.name
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def __repr__(self):
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return self.name
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def __str__(self):
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return '%s p:<%s> d:<%s>' % (self.name,
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','.join(self.provides),
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','.join(self.depends))
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def _get_elements_dir():
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if not os.environ.get('ELEMENTS_PATH'):
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raise Exception("$ELEMENTS_PATH must be set.")
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return os.environ['ELEMENTS_PATH']
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def _expand_element_dependencies(user_elements, all_elements):
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"""Expand user requested elements using element-deps files.
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Arguments:
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:param user_elements: iterable enumerating the elements a user requested
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:param all_elements: Element object dictionary from find_all_elements
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:return: a set containing the names of user_elements and all
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dependent elements including any transitive dependencies.
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"""
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final_elements = set(user_elements)
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check_queue = collections.deque(user_elements)
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provided = set()
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provided_by = collections.defaultdict(list)
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while check_queue:
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# bug #1303911 - run through the provided elements first to avoid
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# adding unwanted dependencies and looking for virtual elements
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element = check_queue.popleft()
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if element in provided:
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continue
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elif element not in all_elements:
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raise MissingElementException("Element '%s' not found" % element)
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element_obj = all_elements[element]
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element_deps = element_obj.depends
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element_provides = element_obj.provides
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# save which elements provide another element for potential
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# error message
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for provide in element_provides:
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provided_by[provide].append(element)
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provided.update(element_provides)
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check_queue.extend(element_deps - (final_elements | provided))
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final_elements.update(element_deps)
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conflicts = set(user_elements) & provided
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if conflicts:
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logger.error(
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"The following elements are already provided by another element")
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for element in conflicts:
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logger.error("%s : already provided by %s",
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element, provided_by[element])
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raise AlreadyProvidedException()
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if "operating-system" not in provided:
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raise MissingOSException("Please include an operating system element")
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out = final_elements - provided
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return([all_elements[element] for element in out])
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def _find_all_elements(paths=None):
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"""Build a dictionary Element() objects
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Walk ELEMENTS_PATH and find all elements. Make an Element object
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for each element we wish to consider. Note we process overrides
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such that elements specified earlier in the ELEMENTS_PATH override
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those seen later.
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:param paths: A list of paths to find elements in. If None will
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use ELEMENTS_PATH from environment
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:return: a dictionary of all elements
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"""
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all_elements = {}
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# note we process the later entries *first*, so that earlier
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# entries will override later ones. i.e. with
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# ELEMENTS_PATH=path1:path2:path3
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# we want the elements in "path1" to override "path3"
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if not paths:
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paths = list(reversed(_get_elements_dir().split(':')))
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else:
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paths = list(reversed(paths.split(':')))
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logger.debug("ELEMENTS_PATH is: %s", ":".join(paths))
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for path in paths:
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if not os.path.isdir(path):
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raise InvalidElementDir("ELEMENTS_PATH entry '%s' "
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"is not a directory " % path)
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# In words : make a list of directories in "path". Since an
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# element is a directory, this is our list of elements.
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elements = [os.path.realpath(os.path.join(path, f))
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for f in os.listdir(path)
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if os.path.isdir(os.path.join(path, f))]
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for element in elements:
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# the element name is the last part of the full path in
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# element (these are all directories, we know that from
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# above)
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name = os.path.basename(element)
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new_element = Element(name, element)
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if name in all_elements:
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logger.warning("Element <%s> overrides <%s>",
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new_element.path, all_elements[name].path)
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all_elements[name] = new_element
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# Now we have all the elements, make a call on each element to
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# store it's reverse dependencies
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for name, element in all_elements.items():
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element._make_rdeps(all_elements)
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return all_elements
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def _get_elements(elements, paths=None):
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"""Return the canonical list of Element objects
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This function returns Element objects. For exernal calls, use
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get_elements which returns a simple tuple & list.
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:param elements: user specified list of elements
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:param paths: element paths, default to environment
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"""
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all_elements = _find_all_elements(paths)
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return _expand_element_dependencies(elements, all_elements)
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def get_elements(elements, paths=None):
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"""Return the canonical list of elements with their dependencies
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.. note::
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You probably do not want to use this! Elements that require
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access to the list of all other elements should generally use
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the environment variables exported by disk-image-create below.
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:param elements: user specified elements
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:param paths: Alternative ELEMENTS_PATH; default is to use from env
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:return: A de-duplicated list of tuples [(element, path),
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(element, path) ...] with all elements and their
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dependents, including any transitive dependencies.
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"""
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elements = _get_elements(elements, paths)
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return [(element.name, element.path) for element in elements]
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def expand_dependencies(user_elements, element_dirs):
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"""Deprecated method for expanding element dependencies.
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.. warning::
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DO NOT USE THIS FUNCTION. For compatibility reasons, this
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function does not provide paths to the returned elements. This
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means the caller must process override rules if two elements
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with the same name appear in element_dirs
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:param user_elements: iterable enumerating the elements a user requested
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:param element_dirs: The ELEMENTS_PATH to process
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:return: a set containing user_elements and all dependent
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elements including any transitive dependencies.
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"""
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logger.warning("expand_dependencies() deprecated, use get_elements")
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elements = _get_elements(user_elements, element_dirs)
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return set([element.name for element in elements])
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def _output_env_vars(elements):
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"""Output eval-able bash strings for IMAGE_ELEMENT vars
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:param elements: list of Element objects to represent
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"""
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# first the "legacy" environment variable that just lists the
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# elements
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print("export IMAGE_ELEMENT='%s'" %
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' '.join([element.name for element in elements]))
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# Then YAML
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output = {}
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for element in elements:
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output[element.name] = element.path
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print("export IMAGE_ELEMENT_YAML='%s'" % yaml.safe_dump(output))
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# Then bash array. Unfortunately, bash can't export array
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# variables. So we take a compromise and produce an exported
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# function that outputs the string to re-create the array.
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# You can then simply do
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# eval declare -A element_array=$(get_image_element_array)
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# and you have it.
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output = ""
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for element in elements:
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output += '[%s]=%s ' % (element.name, element.path)
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print("function get_image_element_array {\n"
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" echo \"%s\"\n"
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"};\n"
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"export -f get_image_element_array;" % output)
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def main():
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diskimage_builder.logging_config.setup()
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parser = argparse.ArgumentParser()
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parser.add_argument('elements', nargs='+',
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help='display dependencies of the given elements')
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parser.add_argument('--env', '-e', action='store_true',
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default=False,
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help=('Output eval-able bash strings for '
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'IMAGE_ELEMENT variables'))
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args = parser.parse_args(sys.argv[1:])
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elements = _get_elements(args.elements)
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if args.env:
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_output_env_vars(elements)
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else:
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# deprecated compatibility output; doesn't include paths.
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print(' '.join([element.name for element in elements]))
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return 0
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if __name__ == "__main__":
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main()
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