Run things as background processes

This fixes #3518, and ensures that we get useful logs and metrics for lots of
things that happen in the background.

(There are certainly more things that happen in the background; these are just
the common ones I've found running a single-process synapse locally).

1 files changed, 4 insertions, 0 deletions

diff --git a/synapse/util/distributor.py b/synapse/util/distributor.py

index 734331caaa..d91ae400eb 100644
--- a/synapse/util/distributor.py
+++ b/synapse/util/distributor.py
@@ -75,6 +75,10 @@ class Distributor(object):
             self.pre_registration[name].append(observer)
 
     def fire(self, name, *args, **kwargs):
+        """Dispatches the given signal to the registered observers.
+
+        Runs the observers as a background process. Does not return a deferred.
+        """
         if name not in self.signals:
             raise KeyError("%r does not have a signal named %s" % (self, name))