core: implement module loading from user-defined directories

Closes #350.

coremods/control.py

@@ -106,6 +106,8 @@ def _rehash():
 
             # TODO: update file loggers here too.
 
+    utils.resetModuleDirs()
+
     for network, sdata in new_conf['servers'].items():
         # Connect any new networks or disconnected networks if they aren't already.
         if (network not in world.networkobjects) or (not world.networkobjects[network].connection_thread.is_alive()):

example-conf.yml

@@ -54,6 +54,11 @@ bot:
     # extra service bots.
     #spawn_services: true
 
+    # Defines extra directories to look up plugins and protocol modules in.
+    # Environment variables (e.g. $HOME) and home folders (~) are expanded here, in that order.
+    #plugin_dirs: ["~/my-plugins", "~/pylink-contrib-modules/plugins"]
+    #protocol_dirs: ["~/pylink-contrib-modules/protocols"]
+
 login:
     # NOTE: for users migrating from PyLink < 1.1, the old login:user/login:password settings
     # have been deprecated. We strongly recommend migrating to the new "accounts:" block below, as

pylink

@@ -62,6 +62,7 @@ if __name__ == '__main__':
     # Import plugins first globally, because they can listen for events
     # that happen before the connection phase.
     to_load = conf.conf['plugins']
+    utils.resetModuleDirs()
     # Here, we override the module lookup and import the plugins
     # dynamically depending on which were configured.
     for plugin in to_load:

utils.py

@@ -14,11 +14,12 @@ import argparse
 
 from .log import log
 from . import world, conf
-# This is just so protocols and plugins are importable.
+
+# Load the protocol and plugin packages.
 from pylinkirc import protocols, plugins
 
-PLUGIN_PREFIX = 'pylinkirc.plugins.'
-PROTOCOL_PREFIX = 'pylinkirc.protocols.'
+PLUGIN_PREFIX = plugins.__name__ + '.'
+PROTOCOL_PREFIX = protocols.__name__ + '.'
 NORMALIZEWHITESPACE_RE = re.compile(r'\s+')
 
 class NotAuthorizedError(Exception):
@@ -147,6 +148,21 @@ def applyModes(irc, target, changedmodes):
     log.warning("(%s) utils.applyModes is deprecated. Use irc.applyModes() instead!", irc.name)
     return irc.applyModes(target, changedmodes)
 
+def expandpath(path):
+    """
+    Returns a path expanded with environment variables and home folders (~) expanded, in that order."""
+    return os.path.expanduser(os.path.expandvars(path))
+
+def resetModuleDirs():
+    """
+    (Re)sets custom protocol module and plugin directories to the ones specified in the config.
+    """
+    # Note: This assumes that the first element of the package path is the default one.
+    plugins.__path__ = [plugins.__path__[0]] + [expandpath(path) for path in conf.conf['bot'].get('plugin_dirs', [])]
+    log.debug('resetModuleDirs: new pylinkirc.plugins.__path__: %s', plugins.__path__)
+    protocols.__path__ = [protocols.__path__[0]] + [expandpath(path) for path in conf.conf['bot'].get('protocol_dirs', [])]
+    log.debug('resetModuleDirs: new pylinkirc.protocols.__path__: %s', protocols.__path__)
+
 def loadPlugin(name):
     """
     Imports and returns the requested plugin.