Python Multiprocessing issue while passing kwargs

Question

I'm trying to create a thread while within a class to start another class constructor but it seems like pool.apply_async isn't passing the kwargs like I would expect it to. Here is my code (trimmed down to only include the threading code):

from MyDatabaseScript import DB

class Trinity:
      def __init__(self):

      #lets split a thread off and work on connecting to the mysql server
      pool = ThreadPool(processes=1) #establish the thread pool

      #I want to pass 'self' as an arg to DB because the Trinity instance has class variables that I want to use
      args, kwargs = (self,), {"host":"my.server.name", "user": "databaseuser", "passwd": "xxxxxxxxxxx", "db": "database name"} 

      async_result = pool.apply_async(DB(), args, kwargs) #create the thread pool call for the DB class with the kwargs

Now that all works fine and I don't get any errors, but on the DB() side my code looks simple and is this:

import MySQLdb

class DB:
      def __init__( self, tms=None, **kwargs ):
          print tms, kwargs

The issue is that the print command within the __init__ function doesn't print anything, I get this:

  None {} 

Answer 1

You are calling DB instead of passing DB to pool.apply_async.

Drop ():

async_result = pool.apply_async(DB, args, kwargs)