Pipeline destroys a connection in the pool

[thlawiczka]

Lets start with an example:

from tornado import gen
import tornadoredis

POOL = tornadoredis.ConnectionPool(...)

@gen.coroutine
def func():
    client = tornadoredis.Client(connection_pool=POOL, selected_db=0)
    with client.pipeline() as pipe:
          pipe.get('xxx')
          # ....
          yield gen.Task(pipe.execute)
    yield gen.Task(client.disconnect)

Generally it's working, but the connection is destroyed unnecessarily. The next operation takes a connection from the pool and fails with an exception "Tried to read from non-existent connection".

It happens because the Client.pipeline() shares a connection with a new Pipeline object, which also is a Client. Therefore there are two clients using this same Connection object. At the end of the scope, the original Client releases a connection to the pool (via .del()). The Pipeline object also uses a Client.del() but have on information about the pool, so it calls a disconnect().

To solve this, you can simply add an empty impl of .del() to the Pipeline class and expect that creator of the Pipeline will take care about the connection.

Regards, Tom

[leporo]

Thank you. I added an empty implementation of del method as you suggested.

Please check does this change work for you?