Question

I am making a server that listens on a socket. Whenever a new request comes in, the server spawns a new instance of handle_request. Each instance of handle_request.py imports the relevant handler from request_handlers.

server.py
handle_request.py
request_handlers
|_handler_beta
|_handler_1
|_handler_2

While handlerX is a module, request_handlers is not a package. The modules are self-contained and reloaded on each request. The modules may be added, modified or dropped while the program is running.

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Question: What is the way to import a module from an arbitrary directory?

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Doing my homework, I saw that most questions deal with packages, even one is titled “python: import a module from a folder“. Hence I believe this question is distinct. The architecture has been simplified; and yes, I am considering pre-forking with reload on file modification.

Answer 1

Create __init__.py in the directory. That makes it a package. If you’re scanning the directory for .py files, you’ll probably then want to skip __init__.py.

Then, you can import them with __import__('request_handlers.' + module, fromlist=['']) (the fromlist is important, otherwise you’ll get request_handlers rather than the appropriate module).

One way of doing it without an __init__.py would be to put the request_handlers directory in sys.path, but that then makes name clashes with other modules possible. Another way would be with execfile. You can research that more if you want to. I’d do it (and have done it before) the package/__import__ way.