"""provide an abstract class for external sources using a sqlite database helper
:organization: Logilab
:copyright: 2007-2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
"""
__docformat__ = "restructuredtext en"
import time
import threading
from os.path import join, exists
from cubicweb import server
from cubicweb.server.sqlutils import SQL_PREFIX, sqlexec, SQLAdapterMixIn
from cubicweb.server.sources import AbstractSource, native
from cubicweb.server.sources.rql2sql import SQLGenerator
def timeout_acquire(lock, timeout):
while not lock.acquire(False):
time.sleep(0.2)
timeout -= 0.2
if timeout <= 0:
raise RuntimeError("svn source is busy, can't acquire connection lock")
class ConnectionWrapper(object):
def __init__(self, source=None):
self.source = source
self._cnx = None
@property
def cnx(self):
if self._cnx is None:
timeout_acquire(self.source._cnxlock, 5)
self._cnx = self.source._sqlcnx
return self._cnx
def commit(self):
if self._cnx is not None:
self._cnx.commit()
def rollback(self):
if self._cnx is not None:
self._cnx.rollback()
def cursor(self):
return self.cnx.cursor()
class SQLiteAbstractSource(AbstractSource):
"""an abstract class for external sources using a sqlite database helper
"""
sqlgen_class = SQLGenerator
@classmethod
def set_nonsystem_types(cls):
# those entities are only in this source, we don't want them in the
# system source
for etype in cls.support_entities:
native.NONSYSTEM_ETYPES.add(etype)
for rtype in cls.support_relations:
native.NONSYSTEM_RELATIONS.add(rtype)
options = (
('helper-db-path',
{'type' : 'string',
'default': None,
'help': 'path to the sqlite database file used to do queries on the \
repository.',
'inputlevel': 2,
}),
)
def __init__(self, repo, appschema, source_config, *args, **kwargs):
# the helper db is used to easy querying and will store everything but
# actual file content
dbpath = source_config.get('helper-db-path')
if dbpath is None:
dbpath = join(repo.config.appdatahome,
'%(uri)s.sqlite' % source_config)
self.dbpath = dbpath
self.sqladapter = SQLAdapterMixIn({'db-driver': 'sqlite',
'db-name': dbpath})
# those attributes have to be initialized before ancestor's __init__
# which will call set_schema
self._need_sql_create = not exists(dbpath)
self._need_full_import = self._need_sql_create
AbstractSource.__init__(self, repo, appschema, source_config,
*args, **kwargs)
# sql database can only be accessed by one connection at a time, and a
# connection can only be used by the thread which created it so:
# * create the connection when needed
# * use a lock to be sure only one connection is used
self._cnxlock = threading.Lock()
@property
def _sqlcnx(self):
# XXX: sqlite connections can only be used in the same thread, so
# create a new one each time necessary. If it appears to be time
# consuming, find another way
return self.sqladapter.get_connection()
def _is_schema_complete(self):
for etype in self.support_entities:
if not etype in self.schema:
self.warning('not ready to generate %s database, %s support missing from schema',
self.uri, etype)
return False
for rtype in self.support_relations:
if not rtype in self.schema:
self.warning('not ready to generate %s database, %s support missing from schema',
self.uri, rtype)
return False
return True
def _create_database(self):
from yams.schema2sql import eschema2sql, rschema2sql
from cubicweb.toolsutils import restrict_perms_to_user
self.warning('initializing sqlite database for %s source' % self.uri)
cnx = self._sqlcnx
cu = cnx.cursor()
schema = self.schema
for etype in self.support_entities:
eschema = schema.eschema(etype)
createsqls = eschema2sql(self.sqladapter.dbhelper, eschema,
skip_relations=('data',), prefix=SQL_PREFIX)
sqlexec(createsqls, cu, withpb=False)
for rtype in self.support_relations:
rschema = schema.rschema(rtype)
if not rschema.inlined:
sqlexec(rschema2sql(rschema), cu, withpb=False)
cnx.commit()
cnx.close()
self._need_sql_create = False
if self.repo.config['uid']:
from logilab.common.shellutils import chown
# database file must be owned by the uid of the server process
self.warning('set %s as owner of the database file',
self.repo.config['uid'])
chown(self.dbpath, self.repo.config['uid'])
restrict_perms_to_user(self.dbpath, self.info)
def set_schema(self, schema):
super(SQLiteAbstractSource, self).set_schema(schema)
if self._need_sql_create and self._is_schema_complete() and self.dbpath:
self._create_database()
self.rqlsqlgen = self.sqlgen_class(schema, self.sqladapter.dbhelper)
def get_connection(self):
return ConnectionWrapper(self)
def check_connection(self, cnx):
"""check connection validity, return None if the connection is still valid
else a new connection (called when the pool using the given connection is
being attached to a session)
always return the connection to reset eventually cached cursor
"""
return cnx
def pool_reset(self, cnx):
"""the pool using the given connection is being reseted from its current
attached session: release the connection lock if the connection wrapper
has a connection set
"""
if cnx._cnx is not None:
try:
cnx._cnx.close()
cnx._cnx = None
finally:
self._cnxlock.release()
def syntax_tree_search(self, session, union,
args=None, cachekey=None, varmap=None, debug=0):
"""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 self._need_sql_create:
return []
sql, query_args = self.rqlsqlgen.generate(union, args)
if server.DEBUG:
print self.uri, 'SOURCE RQL', union.as_string()
print 'GENERATED SQL', sql
args = self.sqladapter.merge_args(args, query_args)
cursor = session.pool[self.uri]
cursor.execute(sql, args)
return self.sqladapter.process_result(cursor)
def local_add_entity(self, session, entity):
"""insert the entity in the local database.
This is not provided as add_entity implementation since usually source
don't want to simply do this, so let raise NotImplementedError and the
source implementor may use this method if necessary
"""
cu = session.pool[self.uri]
attrs = self.sqladapter.preprocess_entity(entity)
sql = self.sqladapter.sqlgen.insert(SQL_PREFIX + str(entity.e_schema), attrs)
cu.execute(sql, attrs)
def add_entity(self, session, entity):
"""add a new entity to the source"""
raise NotImplementedError()
def local_update_entity(self, session, entity, attrs=None):
"""update an entity in the source
This is not provided as update_entity implementation since usually
source don't want to simply do this, so let raise NotImplementedError
and the source implementor may use this method if necessary
"""
cu = session.pool[self.uri]
if attrs is None:
attrs = self.sqladapter.preprocess_entity(entity)
sql = self.sqladapter.sqlgen.update(SQL_PREFIX + str(entity.e_schema),
attrs, [SQL_PREFIX + 'eid'])
cu.execute(sql, attrs)
def update_entity(self, session, entity):
"""update an entity in the source"""
raise NotImplementedError()
def delete_entity(self, session, etype, eid):
"""delete an entity from the source
this is not deleting a file in the svn but deleting entities from the
source. Main usage is to delete repository content when a Repository
entity is deleted.
"""
sqlcursor = session.pool[self.uri]
attrs = {SQL_PREFIX + 'eid': eid}
sql = self.sqladapter.sqlgen.delete(SQL_PREFIX + etype, attrs)
sqlcursor.execute(sql, attrs)
def delete_relation(self, session, subject, rtype, object):
"""delete a relation from the source"""
rschema = self.schema.rschema(rtype)
if rschema.inlined:
if subject in session.query_data('pendingeids', ()):
return
table = SQL_PREFIX + session.describe(subject)[0]
column = SQL_PREFIX + rtype
sql = 'UPDATE %s SET %s=NULL WHERE %seid=%%(eid)s' % (table, column, SQL_PREFIX)
attrs = {'eid' : subject}
else:
attrs = {'eid_from': subject, 'eid_to': object}
sql = self.sqladapter.sqlgen.delete('%s_relation' % rtype, attrs)
sqlcursor = session.pool[self.uri]
sqlcursor.execute(sql, attrs)