use os.pathsep instead of custom implementation

[dneise]

Hi, I was looking for ways to install plugins outside of comet/plugins, when I stumbled over #63.
Looks like exactly what I need :D .. thanks for that!
(I wish it was possible to avoid such an env-var altogether and just detect plugins in all packages on a system, but I assume that is impossible performance wise? ... )

Anyway I think you can save a line and an import here ... os.pathsep does exactly this for you already:
https://docs.python.org/3/library/os.html#os.pathsep

[jdswinbank]

Thank you for this!

I wish it was possible to avoid such an env-var altogether and just detect plugins in all packages on a system

While I don't think it's practical to detect plugins in all packages, if you prefer being able to install plugins as packages you might be able to create packages which just contain comet/plugins/{__init__, pluginname}.py and a setup.py that looks something like this:

from distutils.core import setup

setup(
    name="comet plugin test",
    packages=['comet/plugins']
)

Not the same as scanning all packages, but at least you'd be able to manage your plugins using pip, etc.

I confess my knowledge of Python packaging is rusty, so I might be off on the wrong track here; please let me know if the above works for you and if so I can formalize it in the documentation.

[dneise]

Hi John, thanks for the quick reply.

I'll have a look if this works ... so far my understanding was, that one package shouldn't write into the installation folder of another package (however I did not read anything super explicit about this topic .. so I might be wrong).

Anyway if this does not work, I guess we'll try to use the PLUGINPATH which is available in the master.

[jdswinbank]

You're certainly right that the approach I outline above is ugly... I think it'll work in this case, but no promises.

I'd like to do this “properly” using setuptools entry points (https://setuptools.readthedocs.io/en/latest/userguide/entry_point.html#advertising-behavior). That'll take some more effort to implement, though, and the amount of time I have to spend on Comet is quite limited at the moment. I'll create an issue to experiment with this, and see if I can put something together in a spare moment.

[dneise]

Good Morning John,

Thanks for pointing me to the entry-point docu .. So far I assumed this was only for console scripts, but now I see this is the way pytest deals with plugins .. interesting.

Btw. if your time is limited, I guess us users of comet can also give something back and try to make a PR with some form of "improved" plugin detection.

Just as a side note, in our analysis pipeline prototype for CTA we do a very simple plugin detection based on a package name prefix.
https://github.com/cta-observatory/ctapipe/blob/d853908cfc6933a6b0a5946a4d77911d00ca4b91/ctapipe/core/plugins.py#L7

I assume we can discuss anything else in #71
Btw, I think it is great that you are open to improve this, even though your time is limited.