| # Copyright 2016 Google Inc. 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. |
| |
| """Runtime support code for executables created by Subpar. |
| |
| 1. Third-party modules require some PYTHONPATH manipulation. |
| |
| 2. Python can natively import python modules from a zip archive, but |
| C extension modules require some help. |
| |
| 3. Resources stored in a .par file may need to be exposed as OS-level |
| files instead of Python File objects. |
| |
| We try a succession of different strategies until we find one that |
| works. |
| |
| TODO: Strategy: FUSE filesystem |
| TODO: Strategy: dlopen_with_offset |
| TODO: Strategy: extract all files to a temp dir |
| TODO: Strategy: Do nothing if archive doesn't have any C extension modules |
| |
| """ |
| |
| import os |
| import sys |
| import warnings |
| |
| |
| def _log(msg): |
| """Print a debugging message in the same format as python -vv output""" |
| if sys.flags.verbose: |
| sys.stderr.write(msg) |
| sys.stderr.write('\n') |
| |
| |
| def _find_archive(): |
| """Find the path to the currently executing .par file""" |
| main = sys.modules.get('__main__') |
| if not main: |
| _log('# __main__ module not found') |
| return None |
| main_file = getattr(main, '__file__', None) |
| if not main_file: |
| _log('# __main__.__file__ not set') |
| return None |
| archive_path = os.path.dirname(main_file) |
| if archive_path == '': |
| _log('# unexpected __main__.__file__ is %s' % main_file) |
| return None |
| return archive_path |
| |
| |
| def setup(import_roots=None): |
| """Initialize subpar run-time support""" |
| # Add third-party library entries to sys.path |
| archive_path = _find_archive() |
| if not archive_path: |
| warnings.warn('Failed to initialize .par file runtime support', |
| ImportWarning) |
| return |
| |
| # We try to match to order of Bazel's stub |
| for import_root in reversed(import_roots or []): |
| new_path = os.path.join(archive_path, import_root) |
| _log('# adding %s to sys.path' % new_path) |
| sys.path.insert(1, new_path) |