def __init__(self):
""" Consruct an instance. The instance's open() method must be
called to make it ready for acquireConnection() calls.
"""
self._logger = _getLogger(self.__class__)
self._conn = SteadyDB.connect(** _getCommonSteadyDBArgsDict())
self._logger.debug("Created %s", self.__class__.__name__)
return
def connect(url, setsession=None):
"""
Return connection to database specified by `url`.
"""
scheme, username, password, hostname, port, database = parse_db_url(url)
conn = None
if scheme == "postgresql":
psycopg2 = __import__("psycopg2")
expected_exceptions = (psycopg2.InterfaceError, psycopg2.InternalError,
psycopg2.OperationalError)
try:
if database:
conn = SteadyDB.connect(psycopg2, setsession=setsession,
failures=expected_exceptions,
database=database, user=username,
password=password, host=hostname,
port=port)
else:
conn = SteadyDB.connect(psycopg2, setsession=setsession,
failures=expected_exceptions,
user=username, password=password,
host=hostname, port=port)
except psycopg2.OperationalError as exc:
raise OperationalError(str(exc))
elif scheme == "mysql":
db_api2_mod = __import__("MySQLdb")
try:
conn = SteadyDB.connect(db_api2_mod, setsession=setsession,
db=database, user=username,
passwd=password, host=hostname, port=port)
except db_api2_mod.OperationalError as exc:
raise OperationalError(str(exc))
return conn
def acquireConnection(self):
""" Create a Connection instance.
Parameters:
----------------------------------------------------------------
retval: A ConnectionWrapper instance. NOTE: Caller
is responsible for calling the ConnectionWrapper
instance's release() method or use it in a context manager
expression (with ... as:) to release resources.
"""
self._logger.debug("Acquiring connection")
dbConn = SteadyDB.connect(**_getCommonSteadyDBArgsDict())
connWrap = ConnectionWrapper(
dbConn=dbConn, cursor=dbConn.cursor(), releaser=self._releaseConnection, logger=self._logger
)
return connWrap
def connect_ro(self, **kwargs):
"""
Return new read-only database connection.
The kwargs are merged with the read-only database configuration of the
instance and passed directly to the psycopg2 connect function.
"""
db_conf = self.config["database_ro"]
merged_kwargs = {
"failures": EXPECTED_EXCEPTIONS,
"database": db_conf.get("name"),
"host": db_conf.get("host"),
"port": db_conf.get("port")}
merged_kwargs.update(kwargs)
return SteadyDB.connect(psycopg2, **merged_kwargs)
