Simon Ward <simon+pyt...@bleah.co.uk> writes:
> On Thu, Mar 16, 2023 at 07:45:18AM +1300, dn via Python-list wrote:
>> There is a PyPi library called pluggy (not used it). I've used
>> informal approaches using an ABC as a framework/reminder (see
>> @George's response).
>
> typing.Protocol is also useful here as the plugin interface can be
> defined separately not requiring inheriting from an ABC.
Thanks to all for the helpful suggestions. I realise that I don't
actually need to be able to load a bunch of arbitrary plugins, but
merely to be able to override one (or, perhaps later, more) piece of
default behaviour.
Therefore I think the following very simple scheme will work for me:
$ tree -L 3
.
└── myproj
├── __init__.py
├── mailer.py
├── main.py
└── plugins
└── normanmailer.py
Where main.py is
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
if __name__ == "__main__":
try:
import plugin.mailer as mailer
print("Found plugin.mailer")
except ModuleNotFoundError:
import mailer
print("Found mailer")
m = mailer.Mailer('abc')
m.run()
mailer.py is
class Mailer():
def run(self):
print("This is a generic Mailer object!")
and plugins/normanmailer.py is
class Mailer():
def run(self):
print("This is a customized Mailer object!")
This then gives me
$ poetry run myproj\/main.py
Found mailer
This is a generic Mailer object!
$ mv myproj/plugins/{norman,}mailer.py
$ poetry run myproj\/main.py
Found plugins.mailer
This is a customized Mailer object!
I suspect I was using slightly incorrect/misleading terminology. I
don't want to be able to load arbitrary functionality via plugins,
e.g. sending an email, dumping to a database, uploading to a cloud.
That would, I far as I can tell, necessitate having some mechanism to
select the functionality.
Instead I just want to modify the behaviour of a piece of fixed
functionality. e.g. sending a mail. So am I really talking about
customisation here.
Cheers,
Loris
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