what's better way to share connection pool between inside RequestHandler and outside RequestHandler in tornado

Question

What's the better way to share a connection_pool in both Application/Handler and other place outside Handler like a test file, or a model file?

in main.py , I define a db_pool in Application, I could use it in any RequestHandler, what if I want to use it outside RequestHandler?

What's the better practice?

code in main.py

import tornado.web
class Application(tornado.web.Application):

    """
        自定义的Application
    """

    def __init__(self):
        # I have a db_pool here
        init_dict = {
            'db_pool': PooledDB.PooledDB(MySQLdb, **db_server)
        }

        super(Application, self).__init__(
            [(r'/', IndexHandler, init_dict)],
            **settings)

code in test.py

from main import Application
# I want to get db_pool here

code in dao.py

def get_config(user):
    # I want to get db_pool in main
    db = db_pool.connection()
    return

Could you help me?

Answer 1

I would store the connection pool inside the Application class, instead of passing it to your Handlers . Then, you could access the application inside your handler by calling self.application inside your GET/POST methods.

class Application(tornado.web.Application):

    def __init__(self):
        self.db = PooledDB.PooledDB(MySQLdb, **db_server)
        super(Application, self).__init__([(r'/', IndexHandler)], **settings)

class IndexHandler(tornado.web.RequestHandler):

    def get(self):            
        self.application.db.<put a valid method here>()