def __init__(self,
pool,
dialect,
url,
logging_name=None,
echo=None,
execution_options=None,
loop=None,
**kwargs):
self._engine = Engine(pool,
dialect,
url,
logging_name=logging_name,
echo=echo,
execution_options=execution_options,
**kwargs)
self._loop = loop
max_workers = None
# https://www.python.org/dev/peps/pep-0249/#threadsafety
if dialect.dbapi.threadsafety < 2:
# This might seem overly-restrictive, but when we instantiate an
# AsyncioResultProxy from AsyncioEngine.execute, subsequent
# fetchone calls could be in different threads. Let's limit to one.
max_workers = 1
self._engine_executor = ThreadPoolExecutor(max_workers=max_workers)
def __init__(self, pool, dialect, u, single_worker=True, **kwargs):
if single_worker:
worker = ExecutorThread()
else:
worker = None
self._worker = worker
self._engine = Engine(pool, dialect, u, **kwargs)
def __init__(self,
pool,
dialect,
url,
logging_name=None,
echo=None,
execution_options=None,
**kwargs):
self._engine = Engine(pool,
dialect,
url,
logging_name=logging_name,
echo=echo,
execution_options=execution_options,
**kwargs)
self._engine_worker = None
def mock_sqlalchemy_engine(dialect):
"""
Create a sqlalchemy.engine.Engine without it connecting to a database.
Examples
--------
::
from siuba.sql import LazyTbl
from siuba import _, mutate, show_query
engine = mock_sqlalchemy_engine('postgresql')
tbl = LazyTbl(engine, 'some_table', ['x'])
query = mutate(tbl, y = _.x + _.x)
show_query(query)
"""
from sqlalchemy.engine import Engine
from sqlalchemy.dialects import registry
dialect_cls = registry.load('postgresql')
return Engine(None, dialect_cls(), '')