How to find out the starting point of code execution in any Python project?

Question

I have been looking at various open source GitHub Python projects like, http-prompt and Theano

What I am not able to figure out is where their starting points are, so that I can debug them gracefully. Do I need to look in each and every file for the __main__ method?

I am from Android background; so I was searching something related like AndroidManifest.xml from where I can get an idea as where the code is getting started, but I was unsuccessful in my attempts.

Answer 1

There are two ways a Python script can be loaded:

• By import : import mymodule
• By commandline : $ python mymodule.py

In both cases all code inside the script is executed

Usually if __name__ == '__main__': defines the entry point :

if __name__ == '__main__': 
    print('Started from commandline')
else:
    print('Imported as a module')

In a git project, you can try this to find all scripts made to be launched from command-line :

$ git grep "if __name__ ?== ?\W__main__\W"

Note that the project you mentioned, doesn't contain any explicitly defined entry point, instead the entry point script is generated at packaging time for distribution (see setup.py for this purpose)