CODEWITHSUNDEEP
pythonpython-multithreading
Zath
Zath

Reputation: 11

Access local variable in function from module

I have a function in my main program that attempts to retrieve information from an imported module, which is a different script I wrote. This module spits out a variable which I access from the main program by making it a global.

However, since I'm threading the function that requests the information, the global variable gets polluted by adding the information from separate requests into one var. What I'm looking for is a way to access a local variable in a function in a module.

Main program:

import module

def threaded_function():
    module.function(var1, var2)
    print module.output

Module:

def function(var1, var2):
    global output  
    output = []
    DoThingsWithVars(var1, var2)
    output.append(result)

Since the threading causes it to get accessed multiple times I figured I'd not use global variables and get the local variables for each request. Any idea how I can get at those?

Upvotes: 1

Views: 1557

Answers (1)

Daniel Kluev
Daniel Kluev

Reputation: 11315

Well, the only cases when func locals makes sense are closures and generators. You can access them via __closure__ attribute, but you would have to spawn closure for each separate thread, and it would be easier to just pass thread-local list to function instead.

Other approach, which is actually used sometimes, is to have thread-local globals. Read http://docs.python.org/library/threading.html#threading.local for details. In your case it would work like this:

locs = threading.local()
def function(var1, var2):
    global locs  
    if not locs.output:
        locs.output = []
    DoThingsWithVars(var1, var2)
    locs.output.append(result)

Upvotes: 2

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