Add pluggable components.

 - Adds the notion of a 'plugin'.
   - A plugin has a package path and a flag specifying whether
     it's enabled or not.

 - Adds a find_pluggable_components function similar to the
   find_components one. This one dynamically searches not only
   the mailman package but all of plugins.
   - e.g. find_pluggable_components('rules', IRule) finds
     all IRule components in mailman.rules but also in
     example_plugin.rules for plugin names example_plugin.

 - Uses the find_pluggable_components function in place of
   find_components when searching for Rules, Handlers, Chains,
   EmailCommands, and Styles.

3 files changed, 7 insertions, 8 deletions

diff --git a/src/mailman/core/chains.py b/src/mailman/core/chains.py
index c251d38bc..48ed82d63 100644
--- a/src/mailman/core/chains.py
+++ b/src/mailman/core/chains.py
@@ -19,7 +19,7 @@
 
 from mailman.config import config
 from mailman.interfaces.chain import IChain, LinkAction
-from mailman.utilities.modules import add_components
+from mailman.utilities.plugins import add_pluggable_components
 from public import public
 
 
@@ -89,5 +89,4 @@ def process(mlist, msg, msgdata, start_chain='default-posting-chain'):
 @public
 def initialize():
     """Set up chains, both built-in and from the database."""
-    add_components('mailman.chains', IChain, config.chains)
-    # XXX Read chains from the database and initialize them.
+    add_pluggable_components('chains', IChain, config.chains)
diff --git a/src/mailman/core/pipelines.py b/src/mailman/core/pipelines.py
index 4265d24d1..6e2ad4a27 100644
--- a/src/mailman/core/pipelines.py
+++ b/src/mailman/core/pipelines.py
@@ -24,7 +24,7 @@ from mailman.config import config
 from mailman.interfaces.handler import IHandler
 from mailman.interfaces.pipeline import (
     DiscardMessage, IPipeline, RejectMessage)
-from mailman.utilities.modules import add_components
+from mailman.utilities.plugins import add_pluggable_components
 from public import public
 
 
@@ -63,6 +63,6 @@ def process(mlist, msg, msgdata, pipeline_name='built-in'):
 def initialize():
     """Initialize the pipelines."""
     # Find all handlers in the registered plugins.
-    add_components('mailman.handlers', IHandler, config.handlers)
+    add_pluggable_components('handlers', IHandler, config.handlers)
     # Set up some pipelines.
-    add_components('mailman.pipelines', IPipeline, config.pipelines)
+    add_pluggable_components('pipelines', IPipeline, config.pipelines)
diff --git a/src/mailman/core/rules.py b/src/mailman/core/rules.py
index 8e0d9197c..74934eb99 100644
--- a/src/mailman/core/rules.py
+++ b/src/mailman/core/rules.py
@@ -19,7 +19,7 @@
 
 from mailman.config import config
 from mailman.interfaces.rules import IRule
-from mailman.utilities.modules import add_components
+from mailman.utilities.plugins import add_pluggable_components
 from public import public
 
 
@@ -27,4 +27,4 @@ from public import public
 def initialize():
     """Find and register all rules in all plugins."""
     # Find rules in plugins.
-    add_components('mailman.rules', IRule, config.rules)
+    add_pluggable_components('rules', IRule, config.rules)