class Database(object, metaclass=Singleton):
def __init__(self):
cfg = self.__get_cfg()
self.pool = MySQLConnectionPool(pool_name='dbpool',
pool_size=5,
**cfg)
def __get_cfg(self):
with open('database.yml') as f:
cfg = yaml.load(f.read())['production']
keys = ['username', 'password', 'host', 'port', 'database', 'ssl_ca',
'ssl_cert', 'ssl_key']
no_ = lambda s: s.replace('_', '')
cfg = { k: cfg.get(no_(k)) for k in keys if no_(k) in cfg }
cfg['ssl_verify_cert'] = True
# Mysql documentation incorrectly says 'username' is an alias of 'user'.
cfg['user'] = cfg.pop('username')
return cfg
@contextmanager
def get_connection(self):
def get_conn(attempt=0):
try:
return self.pool.get_connection()
except PoolError:
if 20 > attempt:
time.sleep(0.2)
return get_conn(attempt + 1)
else:
raise
connection = get_conn()
yield connection
# connection.close() will fail with an unread_result.
if connection._cnx.unread_result:
connection._cnx.get_rows()
connection.close()
def close_all(self):
self.pool.reset_session()
