bb384577bc
Instead of putting implementation(s) under the interfaces section put the implementation(s) under there own section. This also includes some other tweaks to refer to those implementation(s) where appropriate. Change-Id: Iffdc0439c843e7f70cf873e5a75501feb51f96c7
406 lines
15 KiB
Python
406 lines
15 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
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# Copyright (C) 2013 Rackspace Hosting All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import errno
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import os
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import shutil
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from oslo.serialization import jsonutils
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import six
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from taskflow import exceptions as exc
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from taskflow import logging
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from taskflow.persistence.backends import base
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from taskflow.persistence import logbook
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from taskflow.utils import lock_utils
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from taskflow.utils import misc
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LOG = logging.getLogger(__name__)
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class DirBackend(base.Backend):
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"""A directory and file based backend.
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This backend writes logbooks, flow details, and atom details to a provided
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base path on the local filesystem. It will create and store those objects
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in three key directories (one for logbooks, one for flow details and one
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for atom details). It creates those associated directories and then
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creates files inside those directories that represent the contents of those
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objects for later reading and writing.
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This backend does *not* provide true transactional semantics. It does
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guarantee that there will be no interprocess race conditions when
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writing and reading by using a consistent hierarchy of file based locks.
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Example configuration::
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conf = {
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"path": "/tmp/taskflow",
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}
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"""
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def __init__(self, conf):
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super(DirBackend, self).__init__(conf)
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self._path = os.path.abspath(conf['path'])
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self._lock_path = os.path.join(self._path, 'locks')
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self._file_cache = {}
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@property
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def lock_path(self):
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return self._lock_path
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@property
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def base_path(self):
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return self._path
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def get_connection(self):
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return Connection(self)
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def close(self):
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pass
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class Connection(base.Connection):
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def __init__(self, backend):
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self._backend = backend
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self._file_cache = self._backend._file_cache
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self._flow_path = os.path.join(self._backend.base_path, 'flows')
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self._atom_path = os.path.join(self._backend.base_path, 'atoms')
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self._book_path = os.path.join(self._backend.base_path, 'books')
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def validate(self):
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# Verify key paths exist.
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paths = [
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self._backend.base_path,
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self._backend.lock_path,
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self._flow_path,
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self._atom_path,
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self._book_path,
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]
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for p in paths:
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if not os.path.isdir(p):
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raise RuntimeError("Missing required directory: %s" % (p))
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def _read_from(self, filename):
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# This is very similar to the oslo-incubator fileutils module, but
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# tweaked to not depend on a global cache, as well as tweaked to not
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# pull-in the oslo logging module (which is a huge pile of code).
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mtime = os.path.getmtime(filename)
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cache_info = self._file_cache.setdefault(filename, {})
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if not cache_info or mtime > cache_info.get('mtime', 0):
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with open(filename, 'rb') as fp:
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cache_info['data'] = fp.read().decode('utf-8')
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cache_info['mtime'] = mtime
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return cache_info['data']
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def _write_to(self, filename, contents):
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if isinstance(contents, six.text_type):
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contents = contents.encode('utf-8')
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with open(filename, 'wb') as fp:
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fp.write(contents)
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self._file_cache.pop(filename, None)
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def _run_with_process_lock(self, lock_name, functor, *args, **kwargs):
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lock_path = os.path.join(self.backend.lock_path, lock_name)
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with lock_utils.InterProcessLock(lock_path):
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try:
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return functor(*args, **kwargs)
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except exc.TaskFlowException:
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raise
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except Exception as e:
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LOG.exception("Failed running locking file based session")
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# NOTE(harlowja): trap all other errors as storage errors.
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raise exc.StorageFailure("Storage backend internal error", e)
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def _get_logbooks(self):
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lb_uuids = []
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try:
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lb_uuids = [d for d in os.listdir(self._book_path)
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if os.path.isdir(os.path.join(self._book_path, d))]
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except EnvironmentError as e:
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if e.errno != errno.ENOENT:
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raise
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for lb_uuid in lb_uuids:
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try:
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yield self._get_logbook(lb_uuid)
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except exc.NotFound:
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pass
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def get_logbooks(self):
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try:
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books = list(self._get_logbooks())
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except EnvironmentError as e:
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raise exc.StorageFailure("Unable to fetch logbooks", e)
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else:
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for b in books:
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yield b
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@property
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def backend(self):
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return self._backend
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def close(self):
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pass
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def _save_atom_details(self, atom_detail, ignore_missing):
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# See if we have an existing atom detail to merge with.
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e_ad = None
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try:
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e_ad = self._get_atom_details(atom_detail.uuid, lock=False)
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except EnvironmentError:
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if not ignore_missing:
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raise exc.NotFound("No atom details found with id: %s"
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% atom_detail.uuid)
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if e_ad is not None:
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atom_detail = e_ad.merge(atom_detail)
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ad_path = os.path.join(self._atom_path, atom_detail.uuid)
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ad_data = base._format_atom(atom_detail)
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self._write_to(ad_path, jsonutils.dumps(ad_data))
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return atom_detail
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def update_atom_details(self, atom_detail):
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return self._run_with_process_lock("atom",
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self._save_atom_details,
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atom_detail,
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ignore_missing=False)
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def _get_atom_details(self, uuid, lock=True):
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def _get():
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ad_path = os.path.join(self._atom_path, uuid)
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ad_data = misc.decode_json(self._read_from(ad_path))
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ad_cls = logbook.atom_detail_class(ad_data['type'])
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return ad_cls.from_dict(ad_data['atom'])
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if lock:
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return self._run_with_process_lock('atom', _get)
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else:
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return _get()
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def _get_flow_details(self, uuid, lock=True):
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def _get():
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fd_path = os.path.join(self._flow_path, uuid)
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meta_path = os.path.join(fd_path, 'metadata')
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meta = misc.decode_json(self._read_from(meta_path))
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fd = logbook.FlowDetail.from_dict(meta)
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ad_to_load = []
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ad_path = os.path.join(fd_path, 'atoms')
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try:
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ad_to_load = [f for f in os.listdir(ad_path)
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if os.path.islink(os.path.join(ad_path, f))]
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except EnvironmentError as e:
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if e.errno != errno.ENOENT:
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raise
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for ad_uuid in ad_to_load:
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fd.add(self._get_atom_details(ad_uuid))
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return fd
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if lock:
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return self._run_with_process_lock('flow', _get)
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else:
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return _get()
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def _save_atoms_and_link(self, atom_details, local_atom_path):
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for atom_detail in atom_details:
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self._save_atom_details(atom_detail, ignore_missing=True)
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src_ad_path = os.path.join(self._atom_path, atom_detail.uuid)
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target_ad_path = os.path.join(local_atom_path, atom_detail.uuid)
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try:
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os.symlink(src_ad_path, target_ad_path)
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except EnvironmentError as e:
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if e.errno != errno.EEXIST:
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raise
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def _save_flow_details(self, flow_detail, ignore_missing):
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# See if we have an existing flow detail to merge with.
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e_fd = None
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try:
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e_fd = self._get_flow_details(flow_detail.uuid, lock=False)
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except EnvironmentError:
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if not ignore_missing:
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raise exc.NotFound("No flow details found with id: %s"
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% flow_detail.uuid)
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if e_fd is not None:
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e_fd = e_fd.merge(flow_detail)
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for ad in flow_detail:
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if e_fd.find(ad.uuid) is None:
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e_fd.add(ad)
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flow_detail = e_fd
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flow_path = os.path.join(self._flow_path, flow_detail.uuid)
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misc.ensure_tree(flow_path)
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self._write_to(os.path.join(flow_path, 'metadata'),
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jsonutils.dumps(flow_detail.to_dict()))
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if len(flow_detail):
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atom_path = os.path.join(flow_path, 'atoms')
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misc.ensure_tree(atom_path)
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self._run_with_process_lock('atom',
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self._save_atoms_and_link,
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list(flow_detail), atom_path)
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return flow_detail
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def update_flow_details(self, flow_detail):
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return self._run_with_process_lock("flow",
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self._save_flow_details,
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flow_detail,
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ignore_missing=False)
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def _save_flows_and_link(self, flow_details, local_flow_path):
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for flow_detail in flow_details:
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self._save_flow_details(flow_detail, ignore_missing=True)
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src_fd_path = os.path.join(self._flow_path, flow_detail.uuid)
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target_fd_path = os.path.join(local_flow_path, flow_detail.uuid)
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try:
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os.symlink(src_fd_path, target_fd_path)
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except EnvironmentError as e:
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if e.errno != errno.EEXIST:
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raise
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def _save_logbook(self, book):
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# See if we have an existing logbook to merge with.
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e_lb = None
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try:
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e_lb = self._get_logbook(book.uuid)
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except exc.NotFound:
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pass
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if e_lb is not None:
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e_lb = e_lb.merge(book)
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for fd in book:
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if e_lb.find(fd.uuid) is None:
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e_lb.add(fd)
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book = e_lb
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book_path = os.path.join(self._book_path, book.uuid)
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misc.ensure_tree(book_path)
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self._write_to(os.path.join(book_path, 'metadata'),
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jsonutils.dumps(book.to_dict(marshal_time=True)))
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if len(book):
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flow_path = os.path.join(book_path, 'flows')
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misc.ensure_tree(flow_path)
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self._run_with_process_lock('flow',
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self._save_flows_and_link,
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list(book), flow_path)
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return book
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def save_logbook(self, book):
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return self._run_with_process_lock("book",
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self._save_logbook, book)
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def upgrade(self):
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def _step_create():
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for path in (self._book_path, self._flow_path, self._atom_path):
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try:
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misc.ensure_tree(path)
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except EnvironmentError as e:
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raise exc.StorageFailure("Unable to create logbooks"
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" required child path %s" % path,
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e)
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for path in (self._backend.base_path, self._backend.lock_path):
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try:
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misc.ensure_tree(path)
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except EnvironmentError as e:
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raise exc.StorageFailure("Unable to create logbooks required"
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" path %s" % path, e)
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self._run_with_process_lock("init", _step_create)
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def clear_all(self):
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def _step_clear():
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for d in (self._book_path, self._flow_path, self._atom_path):
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if os.path.isdir(d):
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shutil.rmtree(d)
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def _step_atom():
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self._run_with_process_lock("atom", _step_clear)
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def _step_flow():
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self._run_with_process_lock("flow", _step_atom)
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def _step_book():
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self._run_with_process_lock("book", _step_flow)
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# Acquire all locks by going through this little hierarchy.
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self._run_with_process_lock("init", _step_book)
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def destroy_logbook(self, book_uuid):
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def _destroy_atoms(atom_details):
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for atom_detail in atom_details:
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atom_path = os.path.join(self._atom_path, atom_detail.uuid)
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try:
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shutil.rmtree(atom_path)
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except EnvironmentError as e:
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if e.errno != errno.ENOENT:
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raise exc.StorageFailure("Unable to remove atom"
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" directory %s" % atom_path,
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e)
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def _destroy_flows(flow_details):
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for flow_detail in flow_details:
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flow_path = os.path.join(self._flow_path, flow_detail.uuid)
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self._run_with_process_lock("atom", _destroy_atoms,
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list(flow_detail))
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try:
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shutil.rmtree(flow_path)
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except EnvironmentError as e:
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if e.errno != errno.ENOENT:
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raise exc.StorageFailure("Unable to remove flow"
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" directory %s" % flow_path,
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e)
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def _destroy_book():
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book = self._get_logbook(book_uuid)
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book_path = os.path.join(self._book_path, book.uuid)
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self._run_with_process_lock("flow", _destroy_flows, list(book))
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try:
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shutil.rmtree(book_path)
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except EnvironmentError as e:
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if e.errno != errno.ENOENT:
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raise exc.StorageFailure("Unable to remove book"
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" directory %s" % book_path, e)
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# Acquire all locks by going through this little hierarchy.
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self._run_with_process_lock("book", _destroy_book)
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def _get_logbook(self, book_uuid):
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book_path = os.path.join(self._book_path, book_uuid)
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meta_path = os.path.join(book_path, 'metadata')
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try:
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meta = misc.decode_json(self._read_from(meta_path))
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except EnvironmentError as e:
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if e.errno == errno.ENOENT:
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raise exc.NotFound("No logbook found with id: %s" % book_uuid)
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else:
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raise
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lb = logbook.LogBook.from_dict(meta, unmarshal_time=True)
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fd_path = os.path.join(book_path, 'flows')
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fd_uuids = []
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try:
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fd_uuids = [f for f in os.listdir(fd_path)
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if os.path.islink(os.path.join(fd_path, f))]
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except EnvironmentError as e:
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if e.errno != errno.ENOENT:
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raise
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for fd_uuid in fd_uuids:
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lb.add(self._get_flow_details(fd_uuid))
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return lb
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def get_logbook(self, book_uuid):
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return self._run_with_process_lock("book",
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self._get_logbook, book_uuid)
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