Reorganize the Handler architecture to a pipeline architecture with plugins.

Now plugins can define additional handlers and the handlers can be organized
into named pipelines.  Modules are no longer the unit of a handler, now we use
classes so we can assert interface conformance.

The GLOBAL_PIPELINE is gone, replaced by the 'built-in' pipeline.  The
OWNER_PIPELINE is not yet replaced.

I still need a few more tests of the basic pipeline architecture, although the
individual handlers have pretty good coverage.

Added the IHandler and IPipeline interfaces.

Still broken, but not yet removed: Mailman/pipeline/moderate.py.

1 files changed, 1 insertions, 0 deletions

diff --git a/Mailman/configuration.py b/Mailman/configuration.py
index 9c850295c..4c9d0a050 100644
--- a/Mailman/configuration.py
+++ b/Mailman/configuration.py
@@ -179,6 +179,7 @@ class Configuration(object):
         # Create the registry of rules and chains.
         self.chains = {}
         self.rules = {}
+        self.handlers = {}
 
     def add_domain(self, email_host, url_host=None):
         """Add a virtual domain.