| # |
| # Copyright (C) 2019 Bloomberg LP |
| # Copyright (C) 2019 Codethink Limited |
| # |
| # This program is free software; you can redistribute it and/or |
| # modify it under the terms of the GNU Lesser General Public |
| # License as published by the Free Software Foundation; either |
| # version 2 of the License, or (at your option) any later version. |
| # |
| # This library 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 |
| # Lesser General Public License for more details. |
| # |
| # You should have received a copy of the GNU Lesser General Public |
| # License along with this library. If not, see <http://www.gnu.org/licenses/>. |
| # |
| |
| """ |
| DownloadableFileSource - Abstract class for sources downloaded from a URI |
| ========================================================================= |
| |
| This DownloadableFileSource class is a convenience class on can derive for |
| implementing sources that get downloaded from a URI. |
| |
| It provides utilities around handling mirrors, tracking and fetching the source. |
| |
| Any derived classes must write their own stage() and get_unique_key() |
| implementation. |
| |
| |
| """ |
| |
| |
| import os |
| import urllib.request |
| import urllib.error |
| import contextlib |
| import shutil |
| import netrc |
| |
| from .source import Source, SourceError |
| from . import utils |
| |
| |
| class _NetrcFTPOpener(urllib.request.FTPHandler): |
| def __init__(self, netrc_config): |
| self.netrc = netrc_config |
| |
| def _unsplit(self, host, port, user, passwd): |
| if port: |
| host = "{}:{}".format(host, port) |
| if user: |
| if passwd: |
| user = "{}:{}".format(user, passwd) |
| host = "{}@{}".format(user, host) |
| |
| return host |
| |
| def ftp_open(self, req): |
| uri = urllib.parse.urlparse(req.full_url) |
| |
| username = uri.username |
| password = uri.password |
| |
| if uri.username is None and self.netrc: |
| entry = self.netrc.authenticators(uri.hostname) |
| if entry: |
| username, _, password = entry |
| |
| req.host = self._unsplit(uri.hostname, uri.port, username, password) |
| |
| return super().ftp_open(req) |
| |
| |
| class _NetrcPasswordManager: |
| def __init__(self, netrc_config): |
| self.netrc = netrc_config |
| |
| def add_password(self, realm, uri, user, passwd): |
| pass |
| |
| def find_user_password(self, realm, authuri): |
| if not self.netrc: |
| return None, None |
| parts = urllib.parse.urlsplit(authuri) |
| entry = self.netrc.authenticators(parts.hostname) |
| if not entry: |
| return None, None |
| else: |
| login, _, password = entry |
| return login, password |
| |
| |
| def _download_file(opener, url, etag, directory): |
| default_name = os.path.basename(url) |
| request = urllib.request.Request(url) |
| request.add_header("Accept", "*/*") |
| request.add_header("User-Agent", "BuildStream/2") |
| |
| if etag is not None: |
| request.add_header("If-None-Match", etag) |
| |
| with contextlib.closing(opener.open(request)) as response: |
| info = response.info() |
| |
| # some servers don't honor the 'If-None-Match' header |
| if etag and info["ETag"] == etag: |
| return None, None |
| |
| etag = info["ETag"] |
| |
| filename = info.get_filename(default_name) |
| filename = os.path.basename(filename) |
| local_file = os.path.join(directory, filename) |
| with open(local_file, "wb") as dest: |
| shutil.copyfileobj(response, dest) |
| |
| return local_file, etag |
| |
| |
| class DownloadableFileSource(Source): |
| # pylint: disable=attribute-defined-outside-init |
| |
| COMMON_CONFIG_KEYS = Source.COMMON_CONFIG_KEYS + ["url", "ref", "etag"] |
| |
| __urlopener = None |
| __default_mirror_file = None |
| |
| def configure(self, node): |
| self.original_url = node.get_str("url") |
| self.ref = node.get_str("ref", None) |
| self.url = self.translate_url(self.original_url) |
| self._mirror_dir = os.path.join(self.get_mirror_directory(), utils.url_directory_name(self.original_url)) |
| self._warn_deprecated_etag(node) |
| |
| def preflight(self): |
| return |
| |
| def get_unique_key(self): |
| return [self.original_url, self.ref] |
| |
| def is_cached(self) -> bool: |
| return os.path.isfile(self._get_mirror_file()) |
| |
| def load_ref(self, node): |
| self.ref = node.get_str("ref", None) |
| self._warn_deprecated_etag(node) |
| |
| def get_ref(self): |
| return self.ref |
| |
| def set_ref(self, ref, node): |
| node["ref"] = self.ref = ref |
| |
| def track(self): # pylint: disable=arguments-differ |
| # there is no 'track' field in the source to determine what/whether |
| # or not to update refs, because tracking a ref is always a conscious |
| # decision by the user. |
| new_ref = self._ensure_mirror("Tracking {}".format(self.url)) |
| |
| if self.ref and self.ref != new_ref: |
| detail = ( |
| "When tracking, new ref differs from current ref:\n" |
| + " Tracked URL: {}\n".format(self.url) |
| + " Current ref: {}\n".format(self.ref) |
| + " New ref: {}\n".format(new_ref) |
| ) |
| self.warn("Potential man-in-the-middle attack!", detail=detail) |
| |
| return new_ref |
| |
| def fetch(self): # pylint: disable=arguments-differ |
| |
| # Just a defensive check, it is impossible for the |
| # file to be already cached because Source.fetch() will |
| # not be called if the source is already cached. |
| # |
| if os.path.isfile(self._get_mirror_file()): |
| return # pragma: nocover |
| |
| # Download the file, raise hell if the sha256sums don't match, |
| # and mirror the file otherwise. |
| sha256 = self._ensure_mirror("Fetching {}".format(self.url),) |
| if sha256 != self.ref: |
| raise SourceError( |
| "File downloaded from {} has sha256sum '{}', not '{}'!".format(self.url, sha256, self.ref) |
| ) |
| |
| def _warn_deprecated_etag(self, node): |
| etag = node.get_str("etag", None) |
| if etag: |
| provenance = node.get_scalar(etag).get_provenance() |
| self.warn('{} "etag" is deprecated and ignored.'.format(provenance)) |
| |
| def _get_etag(self, ref): |
| etagfilename = os.path.join(self._mirror_dir, "{}.etag".format(ref)) |
| if os.path.exists(etagfilename): |
| with open(etagfilename, "r") as etagfile: |
| return etagfile.read() |
| |
| return None |
| |
| def _store_etag(self, ref, etag): |
| etagfilename = os.path.join(self._mirror_dir, "{}.etag".format(ref)) |
| with utils.save_file_atomic(etagfilename) as etagfile: |
| etagfile.write(etag) |
| |
| def _ensure_mirror(self, activity_name: str): |
| # Downloads from the url and caches it according to its sha256sum. |
| try: |
| with self.tempdir() as td: |
| # We do not use etag in case what we have in cache is |
| # not matching ref in order to be able to recover from |
| # corrupted download. |
| if self.ref and not self.is_cached(): |
| # Do not re-download the file if the ETag matches. |
| etag = self._get_etag(self.ref) |
| else: |
| etag = None |
| |
| local_file, new_etag = self.blocking_activity( |
| _download_file, (self.__get_urlopener(), self.url, etag, td), activity_name |
| ) |
| |
| if local_file is None: |
| return self.ref |
| |
| # Make sure url-specific mirror dir exists. |
| if not os.path.isdir(self._mirror_dir): |
| os.makedirs(self._mirror_dir) |
| |
| # Store by sha256sum |
| sha256 = utils.sha256sum(local_file) |
| # Even if the file already exists, move the new file over. |
| # In case the old file was corrupted somehow. |
| os.rename(local_file, self._get_mirror_file(sha256)) |
| |
| if new_etag: |
| self._store_etag(sha256, new_etag) |
| return sha256 |
| |
| except urllib.error.HTTPError as e: |
| if e.code == 304: |
| # 304 Not Modified. |
| # Because we use etag only for matching ref, currently specified ref is what |
| # we would have downloaded. |
| return self.ref |
| raise SourceError("{}: Error mirroring {}: {}".format(self, self.url, e), temporary=True) from e |
| |
| except (urllib.error.URLError, urllib.error.ContentTooShortError, OSError, ValueError) as e: |
| # Note that urllib.request.Request in the try block may throw a |
| # ValueError for unknown url types, so we handle it here. |
| raise SourceError("{}: Error mirroring {}: {}".format(self, self.url, e), temporary=True) from e |
| |
| def _get_mirror_file(self, sha=None): |
| if sha is not None: |
| return os.path.join(self._mirror_dir, sha) |
| |
| if self.__default_mirror_file is None: |
| self.__default_mirror_file = os.path.join(self._mirror_dir, self.ref) |
| |
| return self.__default_mirror_file |
| |
| @classmethod |
| def _reset_url_opener(cls): |
| # Needed for tests, in order to cleanup the `netrc` configuration. |
| cls.__urlopener = None |
| |
| def __get_urlopener(self): |
| if not DownloadableFileSource.__urlopener: |
| try: |
| netrc_config = netrc.netrc() |
| except OSError: |
| # If the .netrc file was not found, FileNotFoundError will be |
| # raised, but OSError will be raised directly by the netrc package |
| # in the case that $HOME is not set. |
| # |
| # This will catch both cases. |
| # |
| DownloadableFileSource.__urlopener = urllib.request.build_opener() |
| except netrc.NetrcParseError as e: |
| self.warn("{}: While reading .netrc: {}".format(self, e)) |
| return urllib.request.build_opener() |
| else: |
| netrc_pw_mgr = _NetrcPasswordManager(netrc_config) |
| http_auth = urllib.request.HTTPBasicAuthHandler(netrc_pw_mgr) |
| ftp_handler = _NetrcFTPOpener(netrc_config) |
| DownloadableFileSource.__urlopener = urllib.request.build_opener(http_auth, ftp_handler) |
| return DownloadableFileSource.__urlopener |
