TypeError: 'tuple' object is not callable while calling multiprocessing in python

Question

I am trying to execute the following script by using multiprocessing and queues,

from googlefinance import getQuotes
from yahoo_finance import Share
import multiprocessing


class Stock:

    def __init__(self,symbol,q):
        self.symbol = symbol
        self.q = q

    def current_value(self):
        current_price =self.q.put(float(getQuotes(self.symbol)[0]['LastTradeWithCurrency']))
        return current_price

    def fundems(self):

        marketcap = self.q.put(Share(self.symbol).get_market_cap())
        bookvalue = self.q.put(Share(self.symbol).get_book_value())
        dividend = self.q.put(Share(self.symbol).get_dividend_share())
        dividend_paydate = self.q.put(Share(self.symbol).get_dividend_pay_date())
        dividend_yield = self.q.put(Share(self.symbol).get_dividend_yield())

        return marketcap, bookvalue, dividend, dividend_paydate, dividend_yield



def main():
    q = multiprocessing.Queue()
    Stock1 = Stock('aapl', q) 


    p1 = multiprocessing.Process(target = Stock1.current_value(), args = (q,))
    p2 = multiprocessing.Process(target = Stock1.fundems(), args = (q,))
    p1.start()
    p2.start()
    p1.join()
    p2.join()

    while q.empty() is False:
        print q.get()


if __name__ == '__main__':
    main()

I am getting the output as the following:

Process Process-2:
Traceback (most recent call last):
  File "/usr/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/lib/python2.7/multiprocessing/process.py", line 114, in run
    self._target(*self._args, **self._kwargs)
TypeError: 'tuple' object is not callable
139.52
732.00B
25.19
2.28
2/16/2017
1.63

Here I see that I am able to get the output which I wanted, but there was an error before that which is kind a making me confused.

Can anyone please help me understand the concept here.

Thanks in advance.

Answer 1

The target should be an uncalled function, you're calling the function in the parent process and trying to launch a Process with the results of the call as the target. Change:

p1 = multiprocessing.Process(target = Stock1.current_value(), args = (q,))
p2 = multiprocessing.Process(target = Stock1.fundems(), args = (q,))

to:

p1 = multiprocessing.Process(target=Stock1.current_value)
p2 = multiprocessing.Process(target=Stock1.fundems)

q is removed as an argument because the object was constructed with q, and uses its own state to access it, it doesn't receive it as an argument to each method.