Python script DB connection as Pool not working, but simple connection is working - mysql

Question

I am writing a script in python 3 that is listening to the tunnel and saving and updating data inside MySQL depend on the message received.
I went into weird behavior, i did a simple connection to MySQL using pymysql module and everything worked fine, ut after sometime this simple connection closes.
So i decide to implement Pool connection to MySQL and here arises the problem. Something happens no errors, but the issue is the following:
My cursor = yield self._pool.execute(query, list(filters.values()))
cursor result = tornado_mysql.pools.Pool object at 0x0000019DE5D71F98
and stacks like that not doing anything more
If i remove yield from cursor pass that line and next line throws error
response = yield c.fetchall()
AttributeError: 'Future' object has no attribute 'fetchall'
How i can fix the MySQL pool connection to work properly?
What i tried:
I use few modules for pool connection, all goes in same issue
Did back simple connection with pymysql and worked again
Below my code:
python script file
import pika
from model import SyncModel
_model = SyncModel(conf, _server_id)
#coroutine
def main():
credentials = pika.PlainCredentials('user', 'password')
try:
cp = pika.ConnectionParameters(
host='127.0.0.1',
port=5671,
credentials=credentials,
ssl=False,
)
connection = pika.BlockingConnection(cp)
channel = connection.channel()
#coroutine
def callback(ch, method, properties, body):
if 'messageType' in properties.headers:
message_type = properties.headers['messageType']
if message_type in allowed_message_types:
result = ptoto_file._reflection.ParseMessage(descriptors[message_type], body)
if result:
result = protobuf_to_dict(result)
if message_type == 'MyMessage':
yield _model.message_event(data=result)
else:
print('Message type not in allowed list = ' + str(message_type))
print('continue listening...')
channel.basic_consume(callback, queue='queue', no_ack=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()
except Exception as e:
print('Could not connect to host 127.0.0.1 on port 5671')
print(str(e))
if __name__ == '__main__':
main()
SyncModel
from tornado_mysql import pools
from tornado.gen import coroutine, Return
from tornado_mysql.cursors import DictCursor
class SyncModel(object):
def __init__(self, conf, server_id):
self.conf = conf
servers = [i for i in conf.mysql.servers]
for s in servers:
if s['server_id'] == server_id:
// s hold all data as, host, user, port, autocommit, charset, db, password
s['cursorclass'] = DictCursor
self._pool = pools.Pool(s, max_idle_connections=1, max_recycle_sec=3)
#coroutine
def message_event(self, data):
table_name = 'table_name'
query = ''
data = data['message']
filters = {
'id': data['id']
}
// here the connection fails as describe above
response = yield self.query_select(table_name, self._pool, filters=filters)
#coroutine
def query_select(self, table_name, _pool, filters=None):
if filters is None:
filters = {}
combined_filters = ['`%s` = %%s' % i for i in filters.keys()]
where = 'WHERE ' + ' AND '.join(combined_filters) if combined_filters else ''
query = """SELECT * FROM `%s` %s""" % (table_name, where)
c = self._pool.execute(query, list(filters.values()))
response = yield c.fetchall()
raise Return({response})
All the code was working with just simple connection to the database, after i start to use pool example is not working anymore. Will appreciate any help in this issue.
This is a stand alone script.

Answer 1

The pool connection was not working, so switched back to pymysql with double checking the connection
I would like to post my answer that worked, only this solution worked for me
before connecting to mysql to check if the connection is open, if not reconnect
if not self.mysql.open:
self.mysql.ping(reconnect=True)