def __init__(self, connection_uri, dbtype="mysql", **kwargs):
if not connection_uri:
raise IllegalArgumentException("The database connection URI is required")
super(Backend, self).__init__()
self._session = None
self._uri = dbtype + CONNECTION_URI_DELIM + connection_uri
self._dbtype = dbtype
self._tables = {}
"""
TODO verify that 'create_engine' and 'MetaData __init__' don't have conflicting args -
if so, then being a cowboy and passing in kwargs will not work.
This will need testing obv...we might actually have to expand kwargs out rather than
passing it in.
"""
self._engine = create_engine(self._uri, **kwargs)
self._meta = MetaData(bind=self._engine, **kwargs)
if kwargs.get("load", False):
self._meta.reflect(**kwargs)
class SQL(Backend):
"""
Wrapper object to adapt data source model for use with a Transactor
"""
def __init__(self, connection_uri, dbtype="mysql", **kwargs):
if not connection_uri:
raise IllegalArgumentException("The database connection URI is required")
super(Backend, self).__init__()
self._session = None
self._uri = dbtype + CONNECTION_URI_DELIM + connection_uri
self._dbtype = dbtype
self._tables = {}
"""
TODO verify that 'create_engine' and 'MetaData __init__' don't have conflicting args -
if so, then being a cowboy and passing in kwargs will not work.
This will need testing obv...we might actually have to expand kwargs out rather than
passing it in.
"""
self._engine = create_engine(self._uri, **kwargs)
self._meta = MetaData(bind=self._engine, **kwargs)
if kwargs.get("load", False):
self._meta.reflect(**kwargs)
@property
def engine(self):
return self._engine
@property
def meta(self):
return self._meta
@property
def tables(self):
return self._tables
###########################################################################
# Instance functionality
#
# The following methods provide an interface/proxy to the current Session
###########################################################################
def unbind(self):
pass #TODO unbind sqlalchemy session
def destroy(self):
self.unbind()
# TODO Any additional cleanup on the table? Drop the table from the session?
def defaults(self):
# TODO
pass
def to_string(self):
return self._uri
def clear(self):
self._meta.clear()
###########################################################################
# CRUD API
###########################################################################
def get(self, name):
"""
Loads a Table from the Database.
If the tables have already been loaded (either in Meta or SQL), then the
cached object is returned; otherwise get creates a new Table Object.
:param name:
:param method:
:return:
"""
if name in self.tables:
return self.tables[name]
_table = None
try:
_table = self.meta.tables[name]
except KeyError:
pass
table = Table(self.engine, self.meta)
self._tables[name] = _table
return table
@coroutine
def create(self, model, **kwargs):
pass
@coroutine
def update(self, model, **kwargs):
# Updates a new row with the specified content
if not model:
raise IllegalArgumentException("'model' is required")
_sync_stratey = kwargs.pop("synchronize_session", "evaluate")
_update_args = kwargs.pop("update_args", None)
_ret = self.session.query(self)
name = model.name
if name:
_ret = _ret.get(name)
_ret.filter_by(kwargs).update(model.export(), synchronize_session=_sync_stratey, update_args=_update_args)
@coroutine
def replace(self, model, **kwargs):
# Replace is semantically no different than update in SQLAlchemy
self.update(model, **kwargs)
@coroutine
def delete(self, model, **kwargs):
# Deletes rows matched by a query
# TODO do we need to consider session.expunge?
_sync_stratey = kwargs.pop("synchronize_session", "evaluate")
_ret = self.session.query(self)
name = model.name
if name:
_ret = _ret.get(name)
_ret.filter_by(kwargs).delete(synchronize_session=_sync_stratey)
###########################################################################
# Transactional API
###########################################################################
def close(self):
if self._session:
self._session.close()
self._session = None
def commit(self):
if not self._session:
raise IllegalStateException("No Session to commit. You must begin a Session prior to committing")
self._session.commit()
def flush(self):
if not self._session:
raise IllegalStateException("No Session to commit. You must begin a Session prior to flushing")
self._session.flush()
def cancel(self):
if not self._session:
raise IllegalStateException("No Session to commit. You must begin a Session prior to cancelling")
self._session.cancel()
def rollback(self):
if not self._session:
raise IllegalStateException("No Session to rollback. You must begin a Session prior to rolling back one")
self._session.rollback()
if self._session:
self._session.close()
self._session = None
def invalidate(self):
# Useful for calls in except statements
if self._session:
self._session.invalidate()
def begin(self):
self._session = self._session_factory() if not self._session else self._session
return self._session
def tag(self):
if not self._session:
raise IllegalStateException(
"No Session to tag. You must begin a Session prior to tagging (creating a save point)")
return self._session.begin_nested()
def commit(self):
if not self._session:
raise IllegalStateException("No Session to commit. You must begin a Session prior to committing")
self._session.commit()
def flush(self):
if not self._session:
raise IllegalStateException("No Session to commit. You must begin a Session prior to flushing")
self._session.flush()
def cancel(self):
if not self._session:
raise IllegalStateException("No Session to commit. You must begin a Session prior to cancelling")
self._session.cancel()
def rollback(self):
if not self._session:
raise IllegalStateException("No Session to rollback. You must begin a Session prior to rolling back one")
self._session.rollback()
