diskimage-builder/diskimage_builder/element_dependencies.py
James Slagle dee69b1810 Python code refactorings.
This commit refactors the python code in diskimage_builder slightly.  This is
in preparation for a larger review that adds more functionality to the python
code, namely the ability to apply elements to the current system as opposed to
a chroot.  Further, the refactorings can stand on their own for better clarity.
They include:
 - renaming elements.py to element_dependencies.py.  Adds clarity about the
   purpose of this module.
 - updating other code for this rename.
 - move tests into a tests submodule.

Change-Id: I5519cc52398e442b24e33802bae42070d64b0c1d
2013-11-12 10:47:57 -05:00

97 lines
3.2 KiB
Python

# Copyright 2013 Hewlett-Packard Development Company, L.P.
# 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 argparse
import os
import sys
def get_elements_dir():
if not os.environ.get('ELEMENTS_PATH'):
raise Exception("$ELEMENTS_PATH must be set.")
return os.environ['ELEMENTS_PATH']
def dependencies(element, elements_dir=None):
"""Return the non-transitive list of dependencies for a single element.
:param user_elements: iterable enumerating elements a user has requested
:param elements_dir: the elements dir to read from. If not supplied,
inferred by calling get_elements_dir().
:return: a set just containing all elements that the specified element
depends on.
"""
if elements_dir is None:
elements_dir = get_elements_dir()
for path in elements_dir.split(':'):
element_deps_path = (os.path.join(path, element, 'element-deps'))
try:
with open(element_deps_path) as element_deps:
return set([line.strip() for line in element_deps])
except IOError as e:
if os.path.exists(os.path.join(path, element)) and e.errno == 2:
return set()
if e.errno == 2:
continue
else:
raise
sys.stderr.write("ERROR: Element '%s' not found in '%s'\n" %
(element, elements_dir))
exit(-1)
def expand_dependencies(user_elements, elements_dir=None):
"""Expand user requested elements using element-deps files.
Arguments:
:param user_elements: iterable enumerating the elements a user requested
:param elements_dir: the elements dir to read from. Passed directly to
dependencies()
:return: a set containing user_elements and all dependent elements
including any transitive dependencies.
"""
final_elements = set(user_elements)
check_queue = list(user_elements)
while check_queue:
element = check_queue.pop()
deps = dependencies(element, elements_dir)
check_queue.extend(deps - final_elements)
final_elements.update(deps)
return final_elements
def main(argv):
parser = argparse.ArgumentParser()
parser.add_argument('elements', nargs='+',
help='elements to inspect')
parser.add_argument('--expand-dependencies', '-d', action='store_true',
default=False,
help='Print expanded dependencies of all args')
args = parser.parse_args(argv[1:])
if args.expand_dependencies:
print(' '.join(expand_dependencies(args.elements)))
return 0
sys.stderr.write("ERROR: please choose an option.\n")
return -1