On 3/15/2023 2:45 PM, dn via Python-list wrote:
On 16/03/2023 01.47, Loris Bennett wrote:
I have written a program which, as part of the non-core functionality,
contains a module to generate email. This is currently very specific
to my organisation, so the main program contains
import myorg.mailer
This module is specific to my organisation in that it can ask an
internal server to generate individualised salutations for a given UID
which is known within the organisation.
I want to share the code with other institutions, so I would like to
1. replace the organisation-specific mailer with a generic one
2. allow an organisation-specific mailer to be used instead of the
generic one, if so desired
This may call for the plug-in pattern, ie the user will choose whether
to plug-in the specific, or the generic, module.
In Python, we would tend to use a Dependency Injection approach (one of
Uncle Bob's SOLID principles).
[snip]
Here is (slightly modified) plugin code I'm using in one project. You
could use a naming convention to see if there is a plugin for a specific
organizations, or each module could contain a UID variable which you
could inspect to find the desired one. This code is under the MIT
License, so feel free to adapt it if you like.
def import_all_plugins(plugins_import_list, plugin_dir):
"""Import modules from the plugins directory and return a list of them.
If plugins_import_list is not empty or None, only import the ones
listed there. Otherwise import all ".py" files.
RETURNS
a list of successfully imported modules.
"""
modules = []
if not plugins_import_list:
plugins_import_list = []
for root, dirs, files in os.walk(plugin_dir):
if root == plugin_dir:
break
for f in files:
f, ext = os.path.splitext(f)
if ext == '.py':
plugins_import_list.append(f)
for f in plugins_import_list:
try:
mod = importlib.import_module(f'plugins.{f}')
modules.append(mod)
except ImportError as e:
print(f'{__name__}: {f} plugin: {e}')
continue
return modules
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