Python Problems

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Python Problems

This page is meant to document Python issues of general interest to Kodi addon developers.

datetime.strptime

There is an old Python bug which only impacts embedded Python applications, such as the Kodi Python environment. The issue is that datetime.strptime is only initialized once per process, and not every time the embedded environment is reinitialized. This causes datetime.strptime to return None (and perhaps other strange behavior).

Workaround

The workaround is to monkey-patch datetime.strptime so that any user of the Python runtime will use it. It is more voodoo-like, but situations like this are why Python natively supports monkey patching, after all. The typically excellent Python documentation manages to be both thorough and concise simultaneously with regards to datetime.strptime and is well worth reviewing before deciding which angle of attack best suits your use case.; it discusses some of the differences between datetime.strptime and time.strptime.

Patch

This patch simply replaces datetime.strptime with time.strptime as they are nearly identical in function. The original Kodi-specific implementation and its commit history are available on GitHub as part of script.module.kutils. Essentially, the patch is:

import datetime
import time


class proxydt(datetime.datetime):

    @classmethod
    def strptime(cls, date_string, format):
        return datetime.datetime(*(time.strptime(date_string, format)[:6]))


datetime.datetime = proxydt

asyncio

It is a known issue that asyncio module or rather its C-based implementation does not support embedded Python environments that use sub-interpreters, such as Kodi Python environment. Essentially it means that only one addon can start the event loop by calling asyncio.run() and others will fail with RuntimeError.

Workaround

The workaround is to disable C-based asyncio module and use its pure-Python implementation. This can be done by the following code that should be put at the beginning of your addon entrypoint script:

import sys
sys.modules['_asyncio'] = None

You will loose possible performance benefits of asyncio but your async Python code won't fail.