# 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. from __future__ import print_function import difflib import imp import os import shlex import subprocess import sys import time import warnings from django.core.management.templates import BaseCommand # Suppress DeprecationWarnings which clutter the output to the point of # rendering it unreadable. warnings.simplefilter('ignore') def get_module_path(module_name): """Gets the module path without importing anything. Avoids conflicts with package dependencies. (taken from http://github.com/sitkatech/pypatch) """ path = sys.path for name in module_name.split('.'): file_pointer, path, desc = imp.find_module(name, path) path = [path, ] if file_pointer is not None: file_pointer.close() return path[0] class DirContext(object): """Change directory in a context manager. This allows changing directory and to always fall back to the previous directory whatever happens during execution. Usage:: with DirContext('/home/foo') as dircontext: # Some code happening in '/home/foo' # We are back to the previous directory. """ def __init__(self, dirname): self.prevdir = os.path.abspath(os.curdir) os.chdir(dirname) self.curdir = os.path.abspath(os.curdir) def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): os.chdir(self.prevdir) def __str__(self): return self.curdir class Command(BaseCommand): def add_arguments(self, parser): parser.add_argument( '--gendiff', action='store_true', dest='gendiff', default=False, help=('Generate a diff file between local_settings.py and ' 'local_settings.py.example'), ) parser.add_argument( '-f', '--force', action='store_true', dest='force', default=False, help=('Force destination rewriting without warning if the ' 'destination file already exists.'), ) help = ("Creates a local_settings.py file from the " "local_settings.py.example template.") time_fmt = '%Y-%m-%d %H:%M:%S %Z' file_time_fmt = '%Y%m%d%H%M%S%Z' local_settings_example = 'local_settings.py.example' local_settings_file = 'local_settings.py' local_settings_diff = 'local_settings.diff' local_settings_reject_pattern = 'local_settings.py_%s.rej' def __init__(self, *args, **kwargs): super(Command, self).__init__(*args, **kwargs) settings_file = os.path.abspath( get_module_path(os.environ['DJANGO_SETTINGS_MODULE']) ) self.local_settings_dir = os.path.abspath( os.path.join( os.path.realpath(os.path.dirname(settings_file)), 'local' ) ) def gendiff(self, force=False): """Generate a diff between self.local_settings and the example file. """ with DirContext(self.local_settings_dir) as dircontext: if not os.path.exists(self.local_settings_diff) or force: with open(self.local_settings_example, 'r') as fp: example_lines = fp.readlines() with open(self.local_settings_file, 'r') as fp: local_settings_lines = fp.readlines() local_settings_example_mtime = time.strftime( self.time_fmt, time.localtime( os.stat(self.local_settings_example).st_mtime) ) local_settings_mtime = time.strftime( self.time_fmt, time.localtime(os.stat(self.local_settings_file).st_mtime) ) print('generating "%s"...' % os.path.join( dircontext.curdir, self.local_settings_diff) ) with open(self.local_settings_diff, 'w') as fp: for line in difflib.unified_diff( example_lines, local_settings_lines, fromfile=self.local_settings_example, tofile=self.local_settings_file, fromfiledate=local_settings_example_mtime, tofiledate=local_settings_mtime ): fp.write(line) print('\tDONE.') sys.exit(0) else: sys.exit( '"%s" already exists.' % os.path.join(dircontext.curdir, self.local_settings_diff) ) def patch(self, force=False): """Patch local_settings.py.example with local_settings.diff. The patch application generates the local_settings.py file (the local_settings.py.example remains unchanged). http://github.com/sitkatech/pypatch fails if the local_settings.py.example file is not 100% identical to the one used to generate the first diff so we use the patch command instead. """ with DirContext(self.local_settings_dir) as dircontext: if os.path.exists(self.local_settings_diff): if not os.path.exists(self.local_settings_file) or force: local_settings_reject = \ self.local_settings_reject_pattern % ( time.strftime(self.file_time_fmt, time.localtime()) ) patch_cmd = shlex.split( 'patch %s %s -o %s -r %s' % ( self.local_settings_example, self.local_settings_diff, self.local_settings_file, local_settings_reject ) ) try: subprocess.check_call(patch_cmd) except subprocess.CalledProcessError: if os.path.exists(local_settings_reject): sys.exit( 'Some conflict(s) occurred. Please check "%s" ' 'to find unapplied parts of the diff.\n' 'Once conflicts are solved, it is safer to ' 'regenerate a newer diff with the "--gendiff" ' 'option.' % os.path.join( dircontext.curdir, local_settings_reject) ) else: sys.exit('An unhandled error occurred.') print('Generation of "%s" successful.' % os.path.join( dircontext.curdir, self.local_settings_file) ) sys.exit(0) else: sys.exit( '"%s" already exists.' % os.path.join(dircontext.curdir, self.local_settings_file) ) else: sys.exit('No diff file found, please generate one with the ' '"--gendiff" option.') def handle(self, *args, **options): force = options.get('force') if options.get('gendiff'): self.gendiff(force) else: self.patch(force)