"""Source to query another RQL repository using pyro
:organization: Logilab
:copyright: 2007-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__docformat__ = "restructuredtext en"
import threading
from os.path import join
from time import mktime
from datetime import datetime
from base64 import b64decode
from Pyro.errors import PyroError, ConnectionClosedError
from logilab.common.configuration import REQUIRED
from rql.nodes import Constant
from rql.utils import rqlvar_maker
from cubicweb import dbapi, server
from cubicweb import BadConnectionId, UnknownEid, ConnectionError
from cubicweb.cwconfig import register_persistent_options
from cubicweb.server.sources import (AbstractSource, ConnectionWrapper,
TimedCache, dbg_st_search, dbg_results)
def uidtype(union, col, etype, args):
select, col = union.locate_subquery(col, etype, args)
return getattr(select.selection[col], 'uidtype', None)
class ReplaceByInOperator(Exception):
def __init__(self, eids):
self.eids = eids
class PyroRQLSource(AbstractSource):
"""External repository source, using Pyro connection"""
# boolean telling if modification hooks should be called when something is
# modified in this source
should_call_hooks = False
# boolean telling if the repository should connect to this source during
# migration
connect_for_migration = False
support_entities = None
options = (
# XXX pyro-ns host/port
('pyro-ns-id',
{'type' : 'string',
'default': REQUIRED,
'help': 'identifier of the repository in the pyro name server',
'group': 'pyro-source', 'inputlevel': 0,
}),
('mapping-file',
{'type' : 'string',
'default': REQUIRED,
'help': 'path to a python file with the schema mapping definition',
'group': 'pyro-source', 'inputlevel': 1,
}),
('cubicweb-user',
{'type' : 'string',
'default': REQUIRED,
'help': 'user to use for connection on the distant repository',
'group': 'pyro-source', 'inputlevel': 0,
}),
('cubicweb-password',
{'type' : 'password',
'default': '',
'help': 'user to use for connection on the distant repository',
'group': 'pyro-source', 'inputlevel': 0,
}),
('base-url',
{'type' : 'string',
'default': '',
'help': 'url of the web site for the distant repository, if you want '
'to generate external link to entities from this repository',
'group': 'pyro-source', 'inputlevel': 1,
}),
('pyro-ns-host',
{'type' : 'string',
'default': None,
'help': 'Pyro name server\'s host. If not set, default to the value \
from all_in_one.conf. It may contains port information using <host>:<port> notation.',
'group': 'pyro-source', 'inputlevel': 1,
}),
('pyro-ns-group',
{'type' : 'string',
'default': None,
'help': 'Pyro name server\'s group where the repository will be \
registered. If not set, default to the value from all_in_one.conf.',
'group': 'pyro-source', 'inputlevel': 1,
}),
('synchronization-interval',
{'type' : 'int',
'default': 5*60,
'help': 'interval between synchronization with the external \
repository (default to 5 minutes).',
'group': 'pyro-source', 'inputlevel': 2,
}),
)
PUBLIC_KEYS = AbstractSource.PUBLIC_KEYS + ('base-url',)
_conn = None
def __init__(self, repo, appschema, source_config, *args, **kwargs):
AbstractSource.__init__(self, repo, appschema, source_config,
*args, **kwargs)
mappingfile = source_config['mapping-file']
if not mappingfile[0] == '/':
mappingfile = join(repo.config.apphome, mappingfile)
mapping = {}
execfile(mappingfile, mapping)
self.support_entities = mapping['support_entities']
self.support_relations = mapping.get('support_relations', {})
self.dont_cross_relations = mapping.get('dont_cross_relations', ())
self.cross_relations = mapping.get('cross_relations', ())
baseurl = source_config.get('base-url')
if baseurl and not baseurl.endswith('/'):
source_config['base-url'] += '/'
self.config = source_config
myoptions = (('%s.latest-update-time' % self.uri,
{'type' : 'int', 'sitewide': True,
'default': 0,
'help': _('timestamp of the latest source synchronization.'),
'group': 'sources',
}),)
register_persistent_options(myoptions)
self._query_cache = TimedCache(30)
def reset_caches(self):
"""method called during test to reset potential source caches"""
self._query_cache = TimedCache(30)
def last_update_time(self):
pkey = u'sources.%s.latest-update-time' % self.uri
rql = 'Any V WHERE X is CWProperty, X value V, X pkey %(k)s'
session = self.repo.internal_session()
try:
rset = session.execute(rql, {'k': pkey})
if not rset:
# insert it
session.execute('INSERT CWProperty X: X pkey %(k)s, X value %(v)s',
{'k': pkey, 'v': u'0'})
session.commit()
timestamp = 0
else:
assert len(rset) == 1
timestamp = int(rset[0][0])
return datetime.fromtimestamp(timestamp)
finally:
session.close()
def init(self):
"""method called by the repository once ready to handle request"""
interval = int(self.config.get('synchronization-interval', 5*60))
self.repo.looping_task(interval, self.synchronize)
self.repo.looping_task(self._query_cache.ttl.seconds/10, self._query_cache.clear_expired)
def synchronize(self, mtime=None):
"""synchronize content known by this repository with content in the
external repository
"""
self.info('synchronizing pyro source %s', self.uri)
cnx = self.get_connection()
try:
extrepo = cnx._repo
except AttributeError:
# fake connection wrapper returned when we can't connect to the
# external source (hence we've no chance to synchronize...)
return
etypes = self.support_entities.keys()
if mtime is None:
mtime = self.last_update_time()
updatetime, modified, deleted = extrepo.entities_modified_since(etypes,
mtime)
self._query_cache.clear()
repo = self.repo
session = repo.internal_session()
try:
for etype, extid in modified:
try:
exturi = cnx.describe(extid)[1]
if exturi == 'system' or not exturi in repo.sources_by_uri:
eid = self.extid2eid(str(extid), etype, session)
rset = session.eid_rset(eid, etype)
entity = rset.get_entity(0, 0)
entity.complete(entity.e_schema.indexable_attributes())
repo.index_entity(session, entity)
except:
self.exception('while updating %s with external id %s of source %s',
etype, extid, self.uri)
continue
for etype, extid in deleted:
try:
eid = self.extid2eid(str(extid), etype, session,
insert=False)
# entity has been deleted from external repository but is not known here
if eid is not None:
repo.delete_info(session, eid)
except:
self.exception('while updating %s with external id %s of source %s',
etype, extid, self.uri)
continue
session.execute('SET X value %(v)s WHERE X pkey %(k)s',
{'k': u'sources.%s.latest-update-time' % self.uri,
'v': unicode(int(mktime(updatetime.timetuple())))})
session.commit()
finally:
session.close()
def _get_connection(self):
"""open and return a connection to the source"""
nshost = self.config.get('pyro-ns-host') or self.repo.config['pyro-ns-host']
nsgroup = self.config.get('pyro-ns-group') or self.repo.config['pyro-ns-group']
#cnxprops = ConnectionProperties(cnxtype=self.config['cnx-type'])
return dbapi.connect(database=self.config['pyro-ns-id'],
login=self.config['cubicweb-user'],
password=self.config['cubicweb-password'],
host=nshost, group=nsgroup,
setvreg=False) #cnxprops=cnxprops)
def get_connection(self):
try:
return self._get_connection()
except (ConnectionError, PyroError):
self.critical("can't get connection to source %s", self.uri,
exc_info=1)
return ConnectionWrapper()
def check_connection(self, cnx):
"""check connection validity, return None if the connection is still valid
else a new connection
"""
# we have to transfer manually thread ownership. This can be done safely
# since the pool to which belong the connection is affected to one
# session/thread and can't be called simultaneously
try:
cnx._repo._transferThread(threading.currentThread())
except AttributeError:
# inmemory connection
pass
if not isinstance(cnx, ConnectionWrapper):
try:
cnx.check()
return # ok
except (BadConnectionId, ConnectionClosedError):
pass
# try to reconnect
return self.get_connection()
def syntax_tree_search(self, session, union, args=None, cachekey=None,
varmap=None):
assert dbg_st_search(self.uri, union, varmap, args, cachekey)
rqlkey = union.as_string(kwargs=args)
try:
results = self._query_cache[rqlkey]
except KeyError:
results = self._syntax_tree_search(session, union, args)
self._query_cache[rqlkey] = results
assert dbg_results(results)
return results
def _syntax_tree_search(self, session, union, args):
"""return result from this source for a rql query (actually from a rql
syntax tree and a solution dictionary mapping each used variable to a
possible type). If cachekey is given, the query necessary to fetch the
results (but not the results themselves) may be cached using this key.
"""
if not args is None:
args = args.copy()
# get cached cursor anyway
cu = session.pool[self.uri]
if cu is None:
# this is a ConnectionWrapper instance
msg = session._("can't connect to source %s, some data may be missing")
session.set_shared_data('sources_error', msg % self.uri)
return []
try:
rql, cachekey = RQL2RQL(self).generate(session, union, args)
except UnknownEid, ex:
if server.DEBUG:
print ' unknown eid', ex, 'no results'
return []
if server.DEBUG & server.DBG_RQL:
print ' translated rql', rql
try:
rset = cu.execute(rql, args, cachekey)
except Exception, ex:
self.exception(str(ex))
msg = session._("error while querying source %s, some data may be missing")
session.set_shared_data('sources_error', msg % self.uri)
return []
descr = rset.description
if rset:
needtranslation = []
rows = rset.rows
for i, etype in enumerate(descr[0]):
if (etype is None or not self.schema.eschema(etype).is_final()
or uidtype(union, i, etype, args)):
needtranslation.append(i)
if needtranslation:
cnx = session.pool.connection(self.uri)
for rowindex in xrange(rset.rowcount - 1, -1, -1):
row = rows[rowindex]
for colindex in needtranslation:
if row[colindex] is not None: # optional variable
etype = descr[rowindex][colindex]
exttype, exturi, extid = cnx.describe(row[colindex])
if exturi == 'system' or not exturi in self.repo.sources_by_uri:
eid = self.extid2eid(str(row[colindex]), etype,
session)
row[colindex] = eid
else:
# skip this row
del rows[rowindex]
del descr[rowindex]
break
results = rows
else:
results = []
return results
def _entity_relations_and_kwargs(self, session, entity):
relations = []
kwargs = {'x': self.eid2extid(entity.eid, session)}
for key, val in entity.iteritems():
relations.append('X %s %%(%s)s' % (key, key))
kwargs[key] = val
return relations, kwargs
def add_entity(self, session, entity):
"""add a new entity to the source"""
raise NotImplementedError()
def update_entity(self, session, entity):
"""update an entity in the source"""
relations, kwargs = self._entity_relations_and_kwargs(session, entity)
cu = session.pool[self.uri]
cu.execute('SET %s WHERE X eid %%(x)s' % ','.join(relations),
kwargs, 'x')
self._query_cache.clear()
entity.clear_all_caches()
def delete_entity(self, session, etype, eid):
"""delete an entity from the source"""
cu = session.pool[self.uri]
cu.execute('DELETE %s X WHERE X eid %%(x)s' % etype,
{'x': self.eid2extid(eid, session)}, 'x')
self._query_cache.clear()
def add_relation(self, session, subject, rtype, object):
"""add a relation to the source"""
cu = session.pool[self.uri]
cu.execute('SET X %s Y WHERE X eid %%(x)s, Y eid %%(y)s' % rtype,
{'x': self.eid2extid(subject, session),
'y': self.eid2extid(object, session)}, ('x', 'y'))
self._query_cache.clear()
session.entity_from_eid(subject).clear_all_caches()
session.entity_from_eid(object).clear_all_caches()
def delete_relation(self, session, subject, rtype, object):
"""delete a relation from the source"""
cu = session.pool[self.uri]
cu.execute('DELETE X %s Y WHERE X eid %%(x)s, Y eid %%(y)s' % rtype,
{'x': self.eid2extid(subject, session),
'y': self.eid2extid(object, session)}, ('x', 'y'))
self._query_cache.clear()
session.entity_from_eid(subject).clear_all_caches()
session.entity_from_eid(object).clear_all_caches()
class RQL2RQL(object):
"""translate a local rql query to be executed on a distant repository"""
def __init__(self, source):
self.source = source
self.current_operator = None
def _accept_children(self, node):
res = []
for child in node.children:
rql = child.accept(self)
if rql is not None:
res.append(rql)
return res
def generate(self, session, rqlst, args):
self._session = session
self.kwargs = args
self.cachekey = []
self.need_translation = False
return self.visit_union(rqlst), self.cachekey
def visit_union(self, node):
s = self._accept_children(node)
if len(s) > 1:
return ' UNION '.join('(%s)' % q for q in s)
return s[0]
def visit_select(self, node):
"""return the tree as an encoded rql string"""
self._varmaker = rqlvar_maker(defined=node.defined_vars.copy())
self._const_var = {}
if node.distinct:
base = 'DISTINCT Any'
else:
base = 'Any'
s = ['%s %s' % (base, ','.join(v.accept(self) for v in node.selection))]
if node.groupby:
s.append('GROUPBY %s' % ', '.join(group.accept(self)
for group in node.groupby))
if node.orderby:
s.append('ORDERBY %s' % ', '.join(self.visit_sortterm(term)
for term in node.orderby))
if node.limit is not None:
s.append('LIMIT %s' % node.limit)
if node.offset:
s.append('OFFSET %s' % node.offset)
restrictions = []
if node.where is not None:
nr = node.where.accept(self)
if nr is not None:
restrictions.append(nr)
if restrictions:
s.append('WHERE %s' % ','.join(restrictions))
if node.having:
s.append('HAVING %s' % ', '.join(term.accept(self)
for term in node.having))
subqueries = []
for subquery in node.with_:
subqueries.append('%s BEING (%s)' % (','.join(ca.name for ca in subquery.aliases),
self.visit_union(subquery.query)))
if subqueries:
s.append('WITH %s' % (','.join(subqueries)))
return ' '.join(s)
def visit_and(self, node):
res = self._accept_children(node)
if res:
return ', '.join(res)
return
def visit_or(self, node):
res = self._accept_children(node)
if len(res) > 1:
return ' OR '.join('(%s)' % rql for rql in res)
elif res:
return res[0]
return
def visit_not(self, node):
rql = node.children[0].accept(self)
if rql:
return 'NOT (%s)' % rql
return
def visit_exists(self, node):
return 'EXISTS(%s)' % node.children[0].accept(self)
def visit_relation(self, node):
try:
if isinstance(node.children[0], Constant):
# simplified rqlst, reintroduce eid relation
try:
restr, lhs = self.process_eid_const(node.children[0])
except UnknownEid:
# can safely skip not relation with an unsupported eid
if node.neged(strict=True):
return
raise
else:
lhs = node.children[0].accept(self)
restr = None
except UnknownEid:
# can safely skip not relation with an unsupported eid
if node.neged(strict=True):
return
# XXX what about optional relation or outer NOT EXISTS()
raise
if node.optional in ('left', 'both'):
lhs += '?'
if node.r_type == 'eid' or not self.source.schema.rschema(node.r_type).is_final():
self.need_translation = True
self.current_operator = node.operator()
if isinstance(node.children[0], Constant):
self.current_etypes = (node.children[0].uidtype,)
else:
self.current_etypes = node.children[0].variable.stinfo['possibletypes']
try:
rhs = node.children[1].accept(self)
except UnknownEid:
# can safely skip not relation with an unsupported eid
if node.neged(strict=True):
return
# XXX what about optional relation or outer NOT EXISTS()
raise
except ReplaceByInOperator, ex:
rhs = 'IN (%s)' % ','.join(eid for eid in ex.eids)
self.need_translation = False
self.current_operator = None
if node.optional in ('right', 'both'):
rhs += '?'
if restr is not None:
return '%s %s %s, %s' % (lhs, node.r_type, rhs, restr)
return '%s %s %s' % (lhs, node.r_type, rhs)
def visit_comparison(self, node):
if node.operator in ('=', 'IS'):
return node.children[0].accept(self)
return '%s %s' % (node.operator.encode(),
node.children[0].accept(self))
def visit_mathexpression(self, node):
return '(%s %s %s)' % (node.children[0].accept(self),
node.operator.encode(),
node.children[1].accept(self))
def visit_function(self, node):
#if node.name == 'IN':
res = []
for child in node.children:
try:
rql = child.accept(self)
except UnknownEid, ex:
continue
res.append(rql)
if not res:
raise ex
return '%s(%s)' % (node.name, ', '.join(res))
def visit_constant(self, node):
if self.need_translation or node.uidtype:
if node.type == 'Int':
return str(self.eid2extid(node.value))
if node.type == 'Substitute':
key = node.value
# ensure we have not yet translated the value...
if not key in self._const_var:
self.kwargs[key] = self.eid2extid(self.kwargs[key])
self.cachekey.append(key)
self._const_var[key] = None
return node.as_string()
def visit_variableref(self, node):
"""get the sql name for a variable reference"""
return node.name
def visit_sortterm(self, node):
if node.asc:
return node.term.accept(self)
return '%s DESC' % node.term.accept(self)
def process_eid_const(self, const):
value = const.eval(self.kwargs)
try:
return None, self._const_var[value]
except:
var = self._varmaker.next()
self.need_translation = True
restr = '%s eid %s' % (var, self.visit_constant(const))
self.need_translation = False
self._const_var[value] = var
return restr, var
def eid2extid(self, eid):
try:
return self.source.eid2extid(eid, self._session)
except UnknownEid:
operator = self.current_operator
if operator is not None and operator != '=':
# deal with query like "X eid > 12"
#
# The problem is that eid order in the external source may
# differ from the local source
#
# So search for all eids from this source matching the condition
# locally and then to replace the "> 12" branch by "IN (eids)"
#
# XXX we may have to insert a huge number of eids...)
sql = "SELECT extid FROM entities WHERE source='%s' AND type IN (%s) AND eid%s%s"
etypes = ','.join("'%s'" % etype for etype in self.current_etypes)
cu = self._session.system_sql(sql % (self.source.uri, etypes,
operator, eid))
# XXX buggy cu.rowcount which may be zero while there are some
# results
rows = cu.fetchall()
if rows:
raise ReplaceByInOperator((b64decode(r[0]) for r in rows))
raise