# copyright 2015 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr -- mailto:contact@logilab.fr
#
# 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 2.1 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
"""Data import of external entities.
Main entry points:
.. autoclass:: ExtEntitiesImporter
.. autoclass:: ExtEntity
Utilities:
.. autofunction:: cwuri2eid
.. autoclass:: RelationMapping
.. autofunction:: cubicweb.dataimport.importer.use_extid_as_cwuri
"""
from collections import defaultdict
import logging
from logilab.mtconverter import xml_escape
def cwuri2eid(cnx, etypes, source_eid=None):
"""Return a dictionary mapping cwuri to eid for entities of the given entity types and / or
source.
"""
assert source_eid or etypes, 'no entity types nor source specified'
rql = 'Any U, X WHERE X cwuri U'
args = {}
if len(etypes) == 1:
rql += ', X is %s' % etypes[0]
elif etypes:
rql += ', X is IN (%s)' % ','.join(etypes)
if source_eid is not None:
rql += ', X cw_source S, S eid %(s)s'
args['s'] = source_eid
return dict(cnx.execute(rql, args))
def use_extid_as_cwuri(extid2eid):
"""Return a generator of :class:`ExtEntity` objects that will set `cwuri`
using entity's extid if the entity does not exist yet and has no `cwuri`
defined.
`extid2eid` is an extid to eid dictionary coming from an
:class:`ExtEntitiesImporter` instance.
Example usage:
.. code-block:: python
importer = SKOSExtEntitiesImporter(cnx, store, import_log)
set_cwuri = use_extid_as_cwuri(importer.extid2eid)
importer.import_entities(set_cwuri(extentities))
"""
def use_extid_as_cwuri_filter(extentities):
for extentity in extentities:
if extentity.extid not in extid2eid:
extentity.values.setdefault('cwuri', set([extentity.extid.decode('utf-8')]))
yield extentity
return use_extid_as_cwuri_filter
class RelationMapping(object):
"""Read-only mapping from relation type to set of related (subject, object) eids.
If `source` is specified, only returns relations implying entities from
this source.
"""
def __init__(self, cnx, source=None):
self.cnx = cnx
self._rql_template = 'Any S,O WHERE S %s O'
self._kwargs = {}
if source is not None:
self._rql_template += ', S cw_source SO, O cw_source SO, SO eid %%(s)s'
self._kwargs['s'] = source.eid
def __getitem__(self, rtype):
"""Return a set of (subject, object) eids already related by `rtype`"""
rql = self._rql_template % rtype
return set(tuple(x) for x in self.cnx.execute(rql, self._kwargs))
class ExtEntity(object):
"""Transitional representation of an entity for use in data importer.
An external entity has the following properties:
* ``extid`` (external id), an identifier for the ext entity,
* ``etype`` (entity type), a string which must be the name of one entity type in the schema
(eg. ``'Person'``, ``'Animal'``, ...),
* ``values``, a dictionary whose keys are attribute or relation names from the schema (eg.
``'first_name'``, ``'friend'``), and whose values are *sets*
For instance:
.. code-block:: python
ext_entity.extid = 'http://example.org/person/debby'
ext_entity.etype = 'Person'
ext_entity.values = {'first_name': set([u"Deborah", u"Debby"]),
'friend': set(['http://example.org/person/john'])}
"""
def __init__(self, etype, extid, values=None):
self.etype = etype
self.extid = extid
if values is None:
values = {}
self.values = values
self._schema = None
def __repr__(self):
return '<%s %s %s>' % (self.etype, self.extid, self.values)
def iter_rdefs(self):
"""Yield (key, rtype, role) defined in `.values` dict, with:
* `key` is the original key in `.values` (i.e. the relation type or a 2-uple (relation type,
role))
* `rtype` is a yams relation type, expected to be found in the schema (attribute or
relation)
* `role` is the role of the entity in the relation, 'subject' or 'object'
Iteration is done on a copy of the keys so values may be inserted/deleted during it.
"""
for key in list(self.values):
if isinstance(key, tuple):
rtype, role = key
assert role in ('subject', 'object'), key
yield key, rtype, role
else:
yield key, key, 'subject'
def prepare(self, schema):
"""Prepare an external entity for later insertion:
* ensure attributes and inlined relations have a single value
* turn set([value]) into value and remove key associated to empty set
* remove non inlined relations and return them as a [(e1key, relation, e2key)] list
Return a list of non inlined relations that may be inserted later, each relations defined by
a 3-tuple (subject extid, relation type, object extid).
Take care the importer may call this method several times.
"""
assert self._schema is None, 'prepare() has already been called for %s' % self
self._schema = schema
eschema = schema.eschema(self.etype)
deferred = []
entity_dict = self.values
for key, rtype, role in self.iter_rdefs():
rschema = schema.rschema(rtype)
if rschema.final or (rschema.inlined and role == 'subject'):
assert len(entity_dict[key]) <= 1, \
"more than one value for %s: %s (%s)" % (rtype, entity_dict[key], self.extid)
if entity_dict[key]:
entity_dict[rtype] = entity_dict[key].pop()
if key != rtype:
del entity_dict[key]
if (rschema.final and eschema.has_metadata(rtype, 'format')
and not rtype + '_format' in entity_dict):
entity_dict[rtype + '_format'] = u'text/plain'
else:
del entity_dict[key]
else:
for target_extid in entity_dict.pop(key):
if role == 'subject':
deferred.append((self.extid, rtype, target_extid))
else:
deferred.append((target_extid, rtype, self.extid))
return deferred
def is_ready(self, extid2eid):
"""Return True if the ext entity is ready, i.e. has all the URIs used in inlined relations
currently existing.
"""
assert self._schema, 'prepare() method should be called first on %s' % self
# as .prepare has been called, we know that .values only contains subject relation *type* as
# key (no more (rtype, role) tuple)
schema = self._schema
entity_dict = self.values
for rtype in entity_dict:
rschema = schema.rschema(rtype)
if not rschema.final:
# .prepare() should drop other cases from the entity dict
assert rschema.inlined
if not entity_dict[rtype] in extid2eid:
return False
# entity is ready, replace all relation's extid by eids
for rtype in entity_dict:
rschema = schema.rschema(rtype)
if rschema.inlined:
entity_dict[rtype] = extid2eid[entity_dict[rtype]]
return True
class ExtEntitiesImporter(object):
"""This class is responsible for importing externals entities, that is instances of
:class:`ExtEntity`, into CubicWeb entities.
:param schema: the CubicWeb's instance schema
:param store: a CubicWeb `Store`
:param extid2eid: optional {extid: eid} dictionary giving information on existing entities. It
will be completed during import. You may want to use :func:`cwuri2eid` to build it.
:param existing_relation: optional {rtype: set((subj eid, obj eid))} mapping giving information on
existing relations of a given type. You may want to use :class:`RelationMapping` to build it.
:param etypes_order_hint: optional ordered iterable on entity types, giving an hint on the order in
which they should be attempted to be imported
:param import_log: optional object implementing the :class:`SimpleImportLog` interface to record
events occuring during the import
:param raise_on_error: optional boolean flag - default to false, indicating whether errors should
be raised or logged. You usually want them to be raised during test but to be logged in
production.
Instances of this class are meant to import external entities through :meth:`import_entities`
which handles a stream of :class:`ExtEntity`. One may then plug arbitrary filters into the
external entities stream.
.. automethod:: import_entities
"""
def __init__(self, schema, store, extid2eid=None, existing_relations=None,
etypes_order_hint=(), import_log=None, raise_on_error=False):
self.schema = schema
self.store = store
self.extid2eid = extid2eid if extid2eid is not None else {}
self.existing_relations = (existing_relations if existing_relations is not None
else defaultdict(set))
self.etypes_order_hint = etypes_order_hint
if import_log is None:
import_log = SimpleImportLog('<unspecified>')
self.import_log = import_log
self.raise_on_error = raise_on_error
# set of created/updated eids
self.created = set()
self.updated = set()
def import_entities(self, ext_entities):
"""Import given external entities (:class:`ExtEntity`) stream (usually a generator)."""
# {etype: [etype dict]} of entities that are in the import queue
queue = {}
# order entity dictionaries then create/update them
deferred = self._import_entities(ext_entities, queue)
# create deferred relations that don't exist already
missing_relations = self.prepare_insert_deferred_relations(deferred)
self._warn_about_missing_work(queue, missing_relations)
def _import_entities(self, ext_entities, queue):
extid2eid = self.extid2eid
deferred = {} # non inlined relations that may be deferred
self.import_log.record_debug('importing entities')
for ext_entity in self.iter_ext_entities(ext_entities, deferred, queue):
try:
eid = extid2eid[ext_entity.extid]
except KeyError:
self.prepare_insert_entity(ext_entity)
else:
if ext_entity.values:
self.prepare_update_entity(ext_entity, eid)
return deferred
def iter_ext_entities(self, ext_entities, deferred, queue):
"""Yield external entities in an order which attempts to satisfy
schema constraints (inlined / cardinality) and to optimize the import.
"""
schema = self.schema
extid2eid = self.extid2eid
order_hint = list(self.etypes_order_hint)
for ext_entity in ext_entities:
# check data in the transitional representation and prepare it for
# later insertion in the database
for subject_uri, rtype, object_uri in ext_entity.prepare(schema):
deferred.setdefault(rtype, set()).add((subject_uri, object_uri))
if not ext_entity.is_ready(extid2eid):
queue.setdefault(ext_entity.etype, []).append(ext_entity)
continue
yield ext_entity
if not queue:
continue
# check for some entities in the queue that may now be ready. We'll have to restart
# search for ready entities until no one is generated
for etype in queue:
if etype not in order_hint:
order_hint.append(etype)
new = True
while new:
new = False
for etype in order_hint:
if etype in queue:
new_queue = []
for ext_entity in queue[etype]:
if ext_entity.is_ready(extid2eid):
yield ext_entity
# may unlock entity previously handled within this loop
new = True
else:
new_queue.append(ext_entity)
if new_queue:
queue[etype][:] = new_queue
else:
del queue[etype]
def prepare_insert_entity(self, ext_entity):
"""Call the store to prepare insertion of the given external entity"""
eid = self.store.prepare_insert_entity(ext_entity.etype, **ext_entity.values)
self.extid2eid[ext_entity.extid] = eid
self.created.add(eid)
return eid
def prepare_update_entity(self, ext_entity, eid):
"""Call the store to prepare update of the given external entity"""
self.store.prepare_update_entity(ext_entity.etype, eid, **ext_entity.values)
self.updated.add(eid)
def prepare_insert_deferred_relations(self, deferred):
"""Call the store to insert deferred relations (not handled during insertion/update for
entities). Return a list of relations `[(subj ext id, obj ext id)]` that may not be inserted
because the target entities don't exists yet.
"""
prepare_insert_relation = self.store.prepare_insert_relation
rschema = self.schema.rschema
extid2eid = self.extid2eid
missing_relations = []
for rtype, relations in deferred.items():
self.import_log.record_debug('importing %s %s relations' % (len(relations), rtype))
symmetric = rschema(rtype).symmetric
existing = self.existing_relations[rtype]
for subject_uri, object_uri in relations:
try:
subject_eid = extid2eid[subject_uri]
object_eid = extid2eid[object_uri]
except KeyError as exc:
missing_relations.append((subject_uri, rtype, object_uri, exc))
continue
if (subject_eid, object_eid) not in existing:
prepare_insert_relation(subject_eid, rtype, object_eid)
existing.add((subject_eid, object_eid))
if symmetric:
existing.add((object_eid, subject_eid))
return missing_relations
def _warn_about_missing_work(self, queue, missing_relations):
error = self.import_log.record_error
if queue:
msgs = ["can't create some entities, is there some cycle or "
"missing data?"]
for ext_entities in queue.values():
for ext_entity in ext_entities:
msgs.append(str(ext_entity))
map(error, msgs)
if self.raise_on_error:
raise Exception('\n'.join(msgs))
if missing_relations:
msgs = ["can't create some relations, is there missing data?"]
for subject_uri, rtype, object_uri, exc in missing_relations:
msgs.append("Could not find %s when trying to insert (%s, %s, %s)"
% (exc, subject_uri, rtype, object_uri))
map(error, msgs)
if self.raise_on_error:
raise Exception('\n'.join(msgs))
class SimpleImportLog(object):
"""Fake CWDataImport log using a simple text format.
Useful to display logs in the UI instead of storing them to the
database.
"""
def __init__(self, filename):
self.logs = []
self.filename = filename
def record_debug(self, msg, path=None, line=None):
self._log(logging.DEBUG, msg, path, line)
def record_info(self, msg, path=None, line=None):
self._log(logging.INFO, msg, path, line)
def record_warning(self, msg, path=None, line=None):
self._log(logging.WARNING, msg, path, line)
def record_error(self, msg, path=None, line=None):
self._log(logging.ERROR, msg, path, line)
def record_fatal(self, msg, path=None, line=None):
self._log(logging.FATAL, msg, path, line)
def _log(self, severity, msg, path, line):
encodedmsg = u'%s\t%s\t%s\t%s' % (severity, self.filename,
line or u'', msg)
self.logs.append(encodedmsg)
class HTMLImportLog(SimpleImportLog):
"""Fake CWDataImport log using a simple HTML format."""
def __init__(self, filename):
super(HTMLImportLog, self).__init__(xml_escape(filename))
def _log(self, severity, msg, path, line):
encodedmsg = u'%s\t%s\t%s\t%s<br/>' % (severity, self.filename,
line or u'', xml_escape(msg))
self.logs.append(encodedmsg)