diff options
Diffstat (limited to 'server/src/leap')
| -rw-r--r-- | server/src/leap/soledad/server/__init__.py | 221 | ||||
| -rw-r--r-- | server/src/leap/soledad/server/_version.py | 46 | ||||
| -rw-r--r-- | server/src/leap/soledad/server/auth.py | 63 | ||||
| -rw-r--r-- | server/src/leap/soledad/server/gzip_middleware.py | 67 | ||||
| -rw-r--r-- | server/src/leap/soledad/server/lock_resource.py | 232 |
5 files changed, 382 insertions, 247 deletions
diff --git a/server/src/leap/soledad/server/__init__.py b/server/src/leap/soledad/server/__init__.py index c80b4c68..c170f230 100644 --- a/server/src/leap/soledad/server/__init__.py +++ b/server/src/leap/soledad/server/__init__.py @@ -87,9 +87,6 @@ and lock documents on the shared database is handled by """ import configparser -import time -import hashlib -import os from u1db.remote import http_app @@ -98,10 +95,6 @@ from u1db.remote import http_app from OpenSSL import tsafe old_tsafe = tsafe -from twisted.web.wsgi import WSGIResource -from twisted.internet import reactor -from twisted.internet.error import TimeoutError -from twisted.python.lockfile import FilesystemLock from twisted import version if version.base() == "12.0.0": # Put OpenSSL's tsafe back into place. This can probably be removed if we @@ -110,22 +103,21 @@ if version.base() == "12.0.0": sys.modules['OpenSSL.tsafe'] = old_tsafe from leap.soledad.server.auth import SoledadTokenAuthMiddleware -from leap.soledad.common import ( - SHARED_DB_NAME, - SHARED_DB_LOCK_DOC_ID_PREFIX, -) +from leap.soledad.server.gzip_middleware import GzipMiddleware +from leap.soledad.server.lock_resource import LockResource + +from leap.soledad.common import SHARED_DB_NAME from leap.soledad.common.couch import CouchServerState -from leap.soledad.common.errors import ( - InvalidTokenError, - NotLockedError, - AlreadyLockedError, -) #----------------------------------------------------------------------------- # Soledad WSGI application #----------------------------------------------------------------------------- +MAX_REQUEST_SIZE = 200 # in Mb +MAX_ENTRY_SIZE = 200 # in Mb + + class SoledadApp(http_app.HTTPApp): """ Soledad WSGI application @@ -136,6 +128,9 @@ class SoledadApp(http_app.HTTPApp): The name of the shared database that holds user's encrypted secrets. """ + max_request_size = MAX_REQUEST_SIZE * 1024 * 1024 + max_entry_size = MAX_ENTRY_SIZE * 1024 * 1024 + def __call__(self, environ, start_response): """ Handle a WSGI call to the Soledad application. @@ -149,195 +144,12 @@ class SoledadApp(http_app.HTTPApp): @return: HTTP application results. @rtype: list """ - # ensure the shared database exists - self.state.ensure_database(self.SHARED_DB_NAME) return http_app.HTTPApp.__call__(self, environ, start_response) -# -# LockResource: a lock based on a document in the shared database. -# - -@http_app.url_to_resource.register -class LockResource(object): - """ - Handle requests for locking documents. - - This class uses Twisted's Filesystem lock to manage a lock in the shared - database. - """ - - url_pattern = '/%s/lock/{uuid}' % SoledadApp.SHARED_DB_NAME - """ - """ - - TIMEOUT = 300 # XXX is 5 minutes reasonable? - """ - The timeout after which the lock expires. - """ - - # used for lock doc storage - TIMESTAMP_KEY = '_timestamp' - LOCK_TOKEN_KEY = '_token' - - FILESYSTEM_LOCK_TRIES = 5 - FILESYSTEM_LOCK_SLEEP_SECONDS = 1 - - - def __init__(self, uuid, state, responder): - """ - Initialize the lock resource. Parameters to this constructor are - automatically passed by u1db. - - :param uuid: The user unique id. - :type uuid: str - :param state: The backend database state. - :type state: u1db.remote.ServerState - :param responder: The infrastructure to send responses to client. - :type responder: u1db.remote.HTTPResponder - """ - self._shared_db = state.open_database(SoledadApp.SHARED_DB_NAME) - self._lock_doc_id = '%s%s' % (SHARED_DB_LOCK_DOC_ID_PREFIX, uuid) - self._lock = FilesystemLock( - hashlib.sha512(self._lock_doc_id).hexdigest()) - self._state = state - self._responder = responder - - @http_app.http_method(content=str) - def put(self, content=None): - """ - Handle a PUT request to the lock document. - - A lock is a document in the shared db with doc_id equal to - 'lock-<uuid>' and the timestamp of its creation as content. This - method obtains a threaded-lock and creates a lock document if it does - not exist or if it has expired. - - It returns '201 Created' and a pair containing a token to unlock and - the lock timeout, or '403 AlreadyLockedError' and the remaining amount - of seconds the lock will still be valid. - - :param content: The content of the PUT request. It is only here - because PUT requests with empty content are considered - invalid requests by u1db. - :type content: str - """ - # obtain filesystem lock - if not self._try_obtain_filesystem_lock(): - self._responder.send_response_json(408) # error: request timeout - return - - created_lock = False - now = time.time() - token = hashlib.sha256(os.urandom(10)).hexdigest() # for releasing - lock_doc = self._shared_db.get_doc(self._lock_doc_id) - remaining = self._remaining(lock_doc, now) - - # if there's no lock, create one - if lock_doc is None: - lock_doc = self._shared_db.create_doc( - { - self.TIMESTAMP_KEY: now, - self.LOCK_TOKEN_KEY: token, - }, - doc_id=self._lock_doc_id) - created_lock = True - else: - if remaining == 0: - # lock expired, create new one - lock_doc.content = { - self.TIMESTAMP_KEY: now, - self.LOCK_TOKEN_KEY: token, - } - self._shared_db.put_doc(lock_doc) - created_lock = True - - self._try_release_filesystem_lock() - - # send response to client - if created_lock is True: - self._responder.send_response_json( - 201, timeout=self.TIMEOUT, token=token) # success: created - else: - wire_descr = AlreadyLockedError.wire_description - self._responder.send_response_json( - AlreadyLockedError.status, # error: forbidden - error=AlreadyLockedError.wire_description, remaining=remaining) - - @http_app.http_method(token=str) - def delete(self, token=None): - """ - Delete the lock if the C{token} is valid. - - Delete the lock document in case C{token} is equal to the token stored - in the lock document. - - :param token: The token returned when locking. - :type token: str - - :raise NotLockedError: Raised in case the lock is not locked. - :raise InvalidTokenError: Raised in case the token is invalid for - unlocking. - """ - lock_doc = self._shared_db.get_doc(self._lock_doc_id) - if lock_doc is None or self._remaining(lock_doc, time.time()) == 0: - self._responder.send_response_json( - NotLockedError.status, # error: not found - error=NotLockedError.wire_description) - elif token != lock_doc.content[self.LOCK_TOKEN_KEY]: - self._responder.send_response_json( - InvalidTokenError.status, # error: unauthorized - error=InvalidTokenError.wire_description) - else: - self._shared_db.delete_doc(lock_doc) - self._responder.send_response_json(200) # success: should use 204 - # but u1db does not - # support it. - - def _remaining(self, lock_doc, now): - """ - Return the number of seconds the lock contained in C{lock_doc} is - still valid, when compared to C{now}. - - :param lock_doc: The document containing the lock. - :type lock_doc: u1db.Document - :param now: The time to which to compare the lock timestamp. - :type now: float - - :return: The amount of seconds the lock is still valid. - :rtype: float - """ - if lock_doc is not None: - lock_timestamp = lock_doc.content[self.TIMESTAMP_KEY] - remaining = lock_timestamp + self.TIMEOUT - now - return remaining if remaining > 0 else 0.0 - return 0.0 - - def _try_obtain_filesystem_lock(self): - """ - Try to obtain the file system lock. - - @return: Whether the lock was succesfully obtained. - @rtype: bool - """ - tries = self.FILESYSTEM_LOCK_TRIES - while tries > 0: - try: - return self._lock.lock() - except Exception as e: - tries -= 1 - time.sleep(self.FILESYSTEM_LOCK_SLEEP_SECONDS) - return False - - def _try_release_filesystem_lock(self): - """ - Release the filesystem lock. - """ - try: - self._lock.unlock() - return True - except Exception: - return False +http_app.url_to_resource.register(LockResource) +http_app.SyncResource.max_request_size = MAX_REQUEST_SIZE * 1024 * 1024 +http_app.SyncResource.max_entry_size = MAX_ENTRY_SIZE * 1024 * 1024 #----------------------------------------------------------------------------- @@ -379,8 +191,9 @@ def application(environ, start_response): SoledadApp.SHARED_DB_NAME, SoledadTokenAuthMiddleware.TOKENS_DB) # WSGI application that may be used by `twistd -web` - application = SoledadTokenAuthMiddleware(SoledadApp(state)) - resource = WSGIResource(reactor, reactor.getThreadPool(), application) + application = GzipMiddleware( + SoledadTokenAuthMiddleware(SoledadApp(state))) + return application(environ, start_response) diff --git a/server/src/leap/soledad/server/_version.py b/server/src/leap/soledad/server/_version.py index 85f0e54c..ec611c39 100644 --- a/server/src/leap/soledad/server/_version.py +++ b/server/src/leap/soledad/server/_version.py @@ -17,6 +17,7 @@ git_full = "$Format:%H$" import subprocess import sys + def run_command(args, cwd=None, verbose=False): try: # remember shell=False, so use git.cmd on windows, not just git @@ -36,11 +37,10 @@ def run_command(args, cwd=None, verbose=False): return None return stdout - -import sys import re import os.path + def get_expanded_variables(versionfile_source): # the code embedded in _version.py can just fetch the value of these # variables. When used from setup.py, we don't want to import @@ -48,7 +48,7 @@ def get_expanded_variables(versionfile_source): # used from _version.py. variables = {} try: - f = open(versionfile_source,"r") + f = open(versionfile_source, "r") for line in f.readlines(): if line.strip().startswith("git_refnames ="): mo = re.search(r'=\s*"(.*)"', line) @@ -63,12 +63,13 @@ def get_expanded_variables(versionfile_source): pass return variables + def versions_from_expanded_variables(variables, tag_prefix, verbose=False): refnames = variables["refnames"].strip() if refnames.startswith("$Format"): if verbose: print("variables are unexpanded, not using") - return {} # unexpanded, so not in an unpacked git-archive tarball + return {} # unexpanded, so not in an unpacked git-archive tarball refs = set([r.strip() for r in refnames.strip("()").split(",")]) # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of # just "foo-1.0". If we see a "tag: " prefix, prefer those. @@ -93,13 +94,14 @@ def versions_from_expanded_variables(variables, tag_prefix, verbose=False): r = ref[len(tag_prefix):] if verbose: print("picking %s" % r) - return { "version": r, - "full": variables["full"].strip() } + return {"version": r, + "full": variables["full"].strip()} # no suitable tags, so we use the full revision id if verbose: print("no suitable tags, using full revision id") - return { "version": variables["full"].strip(), - "full": variables["full"].strip() } + return {"version": variables["full"].strip(), + "full": variables["full"].strip()} + def versions_from_vcs(tag_prefix, versionfile_source, verbose=False): # this runs 'git' from the root of the source tree. That either means @@ -116,7 +118,7 @@ def versions_from_vcs(tag_prefix, versionfile_source, verbose=False): here = os.path.abspath(__file__) except NameError: # some py2exe/bbfreeze/non-CPython implementations don't do __file__ - return {} # not always correct + return {} # not always correct # versionfile_source is the relative path from the top of the source tree # (where the .git directory might live) to this file. Invert this to find @@ -126,7 +128,16 @@ def versions_from_vcs(tag_prefix, versionfile_source, verbose=False): for i in range(len(versionfile_source.split("/"))): root = os.path.dirname(root) else: - root = os.path.dirname(here) + root = os.path.dirname( + os.path.join('..', here)) + + ###################################################### + # XXX patch for our specific configuration with + # the three projects leap.soledad.{common, client, server} + # inside the same repo. + ###################################################### + root = os.path.dirname(os.path.join('..', root)) + if not os.path.exists(os.path.join(root, ".git")): if verbose: print("no .git in %s" % root) @@ -141,7 +152,8 @@ def versions_from_vcs(tag_prefix, versionfile_source, verbose=False): return {} if not stdout.startswith(tag_prefix): if verbose: - print("tag '%s' doesn't start with prefix '%s'" % (stdout, tag_prefix)) + print("tag '%s' doesn't start with prefix '%s'" % + (stdout, tag_prefix)) return {} tag = stdout[len(tag_prefix):] stdout = run_command([GIT, "rev-parse", "HEAD"], cwd=root) @@ -153,7 +165,8 @@ def versions_from_vcs(tag_prefix, versionfile_source, verbose=False): return {"version": tag, "full": full} -def versions_from_parentdir(parentdir_prefix, versionfile_source, verbose=False): +def versions_from_parentdir(parentdir_prefix, versionfile_source, + verbose=False): if IN_LONG_VERSION_PY: # We're running from _version.py. If it's from a source tree # (execute-in-place), we can work upwards to find the root of the @@ -163,7 +176,7 @@ def versions_from_parentdir(parentdir_prefix, versionfile_source, verbose=False) here = os.path.abspath(__file__) except NameError: # py2exe/bbfreeze/non-CPython don't have __file__ - return {} # without __file__, we have no hope + return {} # without __file__, we have no hope # versionfile_source is the relative path from the top of the source # tree to _version.py. Invert this to find the root from __file__. root = here @@ -180,7 +193,8 @@ def versions_from_parentdir(parentdir_prefix, versionfile_source, verbose=False) dirname = os.path.basename(root) if not dirname.startswith(parentdir_prefix): if verbose: - print("guessing rootdir is '%s', but '%s' doesn't start with prefix '%s'" % + print("guessing rootdir is '%s', but '%s' doesn't start " + "with prefix '%s'" % (root, dirname, parentdir_prefix)) return None return {"version": dirname[len(parentdir_prefix):], "full": ""} @@ -189,8 +203,9 @@ tag_prefix = "" parentdir_prefix = "leap.soledad.server-" versionfile_source = "src/leap/soledad/server/_version.py" + def get_versions(default={"version": "unknown", "full": ""}, verbose=False): - variables = { "refnames": git_refnames, "full": git_full } + variables = {"refnames": git_refnames, "full": git_full} ver = versions_from_expanded_variables(variables, tag_prefix, verbose) if not ver: ver = versions_from_vcs(tag_prefix, versionfile_source, verbose) @@ -200,4 +215,3 @@ def get_versions(default={"version": "unknown", "full": ""}, verbose=False): if not ver: ver = default return ver - diff --git a/server/src/leap/soledad/server/auth.py b/server/src/leap/soledad/server/auth.py index 0ae49576..e9d2b032 100644 --- a/server/src/leap/soledad/server/auth.py +++ b/server/src/leap/soledad/server/auth.py @@ -25,7 +25,7 @@ import httplib import simplejson as json -from u1db import DBNAME_CONSTRAINTS +from u1db import DBNAME_CONSTRAINTS, errors as u1db_errors from abc import ABCMeta, abstractmethod from routes.mapper import Mapper from couchdb.client import Server @@ -37,16 +37,7 @@ from leap.soledad.common import ( SHARED_DB_LOCK_DOC_ID_PREFIX, USER_DB_PREFIX, ) - - -#----------------------------------------------------------------------------- -# Authentication -#----------------------------------------------------------------------------- - -class Unauthorized(Exception): - """ - User authentication failed. - """ +from leap.soledad.common.errors import InvalidAuthTokenError class URLToAuthorization(object): @@ -279,10 +270,16 @@ class SoledadAuthMiddleware(object): return self._unauthorized_error("Wrong authentication scheme") # verify if user is athenticated - if not self._verify_authentication_data(uuid, auth_data): - return self._unauthorized_error( + try: + if not self._verify_authentication_data(uuid, auth_data): + return self._unauthorized_error( + start_response, + self._get_auth_error_string()) + except u1db_errors.Unauthorized as e: + return self._error( start_response, - self._get_auth_error_string()) + 401, + e.wire_description) # verify if user is authorized to perform action if not self._verify_authorization(environ, uuid): @@ -319,6 +316,9 @@ class SoledadAuthMiddleware(object): @return: Whether the token is valid for authenticating the request. @rtype: bool + + @raise Unauthorized: Raised when C{auth_data} is not enough to + authenticate C{uuid}. """ return None @@ -386,11 +386,20 @@ class SoledadTokenAuthMiddleware(SoledadAuthMiddleware): @return: Whether the token is valid for authenticating the request. @rtype: bool + + @raise Unauthorized: Raised when C{auth_data} is not enough to + authenticate C{uuid}. """ token = auth_data # we expect a cleartext token at this point - return self._verify_token_in_couchdb(uuid, token) + try: + return self._verify_token_in_couch(uuid, token) + except InvalidAuthTokenError: + raise + except Exception as e: + log.err(e) + return False - def _verify_token_in_couchdb(self, uuid, token): + def _verify_token_in_couch(self, uuid, token): """ Query couchdb to decide if C{token} is valid for C{uuid}. @@ -398,19 +407,19 @@ class SoledadTokenAuthMiddleware(SoledadAuthMiddleware): @type uuid: str @param token: The token. @type token: str + + @raise InvalidAuthTokenError: Raised when token received from user is + either missing in the tokens db or is + invalid. """ server = Server(url=self._app.state.couch_url) - try: - dbname = self.TOKENS_DB - db = server[dbname] - token = db.get(token) - if token is None: - return False - return token[self.TOKENS_TYPE_KEY] == self.TOKENS_TYPE_DEF and \ - token[self.TOKENS_USER_ID_KEY] == uuid - except Exception as e: - log.err(e) - return False + dbname = self.TOKENS_DB + db = server[dbname] + token = db.get(token) + if token is None or \ + token[self.TOKENS_TYPE_KEY] != self.TOKENS_TYPE_DEF or \ + token[self.TOKENS_USER_ID_KEY] != uuid: + raise InvalidAuthTokenError() return True def _get_auth_error_string(self): diff --git a/server/src/leap/soledad/server/gzip_middleware.py b/server/src/leap/soledad/server/gzip_middleware.py new file mode 100644 index 00000000..986c5738 --- /dev/null +++ b/server/src/leap/soledad/server/gzip_middleware.py @@ -0,0 +1,67 @@ +# -*- coding: utf-8 -*- +# gzip_middleware.py +# Copyright (C) 2013 LEAP +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program 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 General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. +""" +Gzip middleware for WSGI apps. +""" +import StringIO +from gzip import GzipFile + + +class GzipMiddleware(object): + """ + GzipMiddleware class for WSGI. + """ + def __init__(self, app, compresslevel=9): + self.app = app + self.compresslevel = compresslevel + + def __call__(self, environ, start_response): + if 'gzip' not in environ.get('HTTP_ACCEPT_ENCODING', ''): + return self.app(environ, start_response) + + buffer = StringIO.StringIO() + output = GzipFile( + mode='wb', + compresslevel=self.compresslevel, + fileobj=buffer + ) + + start_response_args = [] + + def dummy_start_response(status, headers, exc_info=None): + start_response_args.append(status) + start_response_args.append(headers) + start_response_args.append(exc_info) + return output.write + + app_iter = self.app(environ, dummy_start_response) + for line in app_iter: + output.write(line) + if hasattr(app_iter, 'close'): + app_iter.close() + output.close() + buffer.seek(0) + result = buffer.getvalue() + headers = [] + for name, value in start_response_args[1]: + if name.lower() != 'content-length': + headers.append((name, value)) + headers.append(('Content-Length', str(len(result)))) + headers.append(('Content-Encoding', 'gzip')) + start_response(start_response_args[0], headers, start_response_args[2]) + buffer.close() + return [result] diff --git a/server/src/leap/soledad/server/lock_resource.py b/server/src/leap/soledad/server/lock_resource.py new file mode 100644 index 00000000..a7870f77 --- /dev/null +++ b/server/src/leap/soledad/server/lock_resource.py @@ -0,0 +1,232 @@ +# -*- coding: utf-8 -*- +# lock_resource.py +# Copyright (C) 2013 LEAP +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program 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 General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + + +""" +LockResource: a lock based on a document in the shared database. +""" + + +import hashlib +import time +import os +import tempfile +import errno + + +from u1db.remote import http_app +from twisted.python.lockfile import FilesystemLock + + +from leap.soledad.common import ( + SHARED_DB_NAME, + SHARED_DB_LOCK_DOC_ID_PREFIX, +) +from leap.soledad.common.errors import ( + InvalidTokenError, + NotLockedError, + AlreadyLockedError, + LockTimedOutError, + CouldNotObtainLockError, +) + + +class LockResource(object): + """ + Handle requests for locking documents. + + This class uses Twisted's Filesystem lock to manage a lock in the shared + database. + """ + + url_pattern = '/%s/lock/{uuid}' % SHARED_DB_NAME + """ + """ + + TIMEOUT = 300 # XXX is 5 minutes reasonable? + """ + The timeout after which the lock expires. + """ + + # used for lock doc storage + TIMESTAMP_KEY = '_timestamp' + LOCK_TOKEN_KEY = '_token' + + FILESYSTEM_LOCK_TRIES = 5 + FILESYSTEM_LOCK_SLEEP_SECONDS = 1 + + def __init__(self, uuid, state, responder): + """ + Initialize the lock resource. Parameters to this constructor are + automatically passed by u1db. + + :param uuid: The user unique id. + :type uuid: str + :param state: The backend database state. + :type state: u1db.remote.ServerState + :param responder: The infrastructure to send responses to client. + :type responder: u1db.remote.HTTPResponder + """ + self._shared_db = state.open_database(SHARED_DB_NAME) + self._lock_doc_id = '%s%s' % (SHARED_DB_LOCK_DOC_ID_PREFIX, uuid) + self._lock = FilesystemLock( + os.path.join( + tempfile.gettempdir(), + hashlib.sha512(self._lock_doc_id).hexdigest())) + self._state = state + self._responder = responder + + @http_app.http_method(content=str) + def put(self, content=None): + """ + Handle a PUT request to the lock document. + + A lock is a document in the shared db with doc_id equal to + 'lock-<uuid>' and the timestamp of its creation as content. This + method obtains a threaded-lock and creates a lock document if it does + not exist or if it has expired. + + It returns '201 Created' and a pair containing a token to unlock and + the lock timeout, or '403 AlreadyLockedError' and the remaining amount + of seconds the lock will still be valid. + + :param content: The content of the PUT request. It is only here + because PUT requests with empty content are considered + invalid requests by u1db. + :type content: str + """ + # obtain filesystem lock + if not self._try_obtain_filesystem_lock(): + self._responder.send_response_json( + LockTimedOutError.status, # error: request timeout + error=LockTimedOutError.wire_description) + return + + created_lock = False + now = time.time() + token = hashlib.sha256(os.urandom(10)).hexdigest() # for releasing + lock_doc = self._shared_db.get_doc(self._lock_doc_id) + remaining = self._remaining(lock_doc, now) + + # if there's no lock, create one + if lock_doc is None: + lock_doc = self._shared_db.create_doc( + { + self.TIMESTAMP_KEY: now, + self.LOCK_TOKEN_KEY: token, + }, + doc_id=self._lock_doc_id) + created_lock = True + else: + if remaining == 0: + # lock expired, create new one + lock_doc.content = { + self.TIMESTAMP_KEY: now, + self.LOCK_TOKEN_KEY: token, + } + self._shared_db.put_doc(lock_doc) + created_lock = True + + self._try_release_filesystem_lock() + + # send response to client + if created_lock is True: + self._responder.send_response_json( + 201, timeout=self.TIMEOUT, token=token) # success: created + else: + self._responder.send_response_json( + AlreadyLockedError.status, # error: forbidden + error=AlreadyLockedError.wire_description, remaining=remaining) + + @http_app.http_method(token=str) + def delete(self, token=None): + """ + Delete the lock if the C{token} is valid. + + Delete the lock document in case C{token} is equal to the token stored + in the lock document. + + :param token: The token returned when locking. + :type token: str + + :raise NotLockedError: Raised in case the lock is not locked. + :raise InvalidTokenError: Raised in case the token is invalid for + unlocking. + """ + lock_doc = self._shared_db.get_doc(self._lock_doc_id) + if lock_doc is None or self._remaining(lock_doc, time.time()) == 0: + self._responder.send_response_json( + NotLockedError.status, # error: not found + error=NotLockedError.wire_description) + elif token != lock_doc.content[self.LOCK_TOKEN_KEY]: + self._responder.send_response_json( + InvalidTokenError.status, # error: unauthorized + error=InvalidTokenError.wire_description) + else: + self._shared_db.delete_doc(lock_doc) + self._responder.send_response_json(200) # success: should use 204 + # but u1db does not + # support it. + + def _remaining(self, lock_doc, now): + """ + Return the number of seconds the lock contained in C{lock_doc} is + still valid, when compared to C{now}. + + :param lock_doc: The document containing the lock. + :type lock_doc: u1db.Document + :param now: The time to which to compare the lock timestamp. + :type now: float + + :return: The amount of seconds the lock is still valid. + :rtype: float + """ + if lock_doc is not None: + lock_timestamp = lock_doc.content[self.TIMESTAMP_KEY] + remaining = lock_timestamp + self.TIMEOUT - now + return remaining if remaining > 0 else 0.0 + return 0.0 + + def _try_obtain_filesystem_lock(self): + """ + Try to obtain the file system lock. + + @return: Whether the lock was succesfully obtained. + @rtype: bool + """ + tries = self.FILESYSTEM_LOCK_TRIES + while tries > 0: + try: + return self._lock.lock() + except OSError as e: + tries -= 1 + if tries == 0: + raise CouldNotObtainLockError(e.message) + time.sleep(self.FILESYSTEM_LOCK_SLEEP_SECONDS) + return False + + def _try_release_filesystem_lock(self): + """ + Release the filesystem lock. + """ + try: + self._lock.unlock() + return True + except OSError as e: + if e.errno == errno.ENOENT: + return True + return False |