Add GroupCallbacks to reference documentation

Author: LincolnPuzey

docs/source/global.rst

@@ -11,6 +11,7 @@
 .. |Encoders| replace:: :class:`Encoders<dramatiq.Encoder>`
 .. |GenericActors| replace:: :class:`class-based actors<dramatiq.GenericActor>`
 .. |Groups| replace:: :func:`Groups<dramatiq.group>`
+.. |GroupCallbacks| replace:: :class:`GroupCallbacks<dramatiq.middleware.GroupCallbacks>`
 .. |Interrupt| replace:: :class:`Interrupt<dramatiq.middleware.Interrupt>`
 .. |MemcachedRLBackend| replace:: :class:`Memcached<dramatiq.rate_limits.backends.MemcachedBackend>`
 .. |Messages| replace:: :class:`Messages<dramatiq.Message>`

docs/source/reference.rst

@@ -110,6 +110,7 @@ The following middleware classes are available, but not enabled by default.
 .. autoclass:: dramatiq.middleware.CurrentMessage
    :members: get_current_message
    :member-order: bysource
+.. autoclass:: dramatiq.middleware.GroupCallbacks
 .. autoclass:: dramatiq.middleware.prometheus.Prometheus
 
 .. py:class:: dramatiq.results.Results

dramatiq/composition.py

@@ -206,7 +206,7 @@ def add_completion_callback(self, message):
         callbacks.
 
         Warning:
-          This functionality is dependent upon the GroupCallbacks
+          This functionality is dependent upon the optional |GroupCallbacks|
           middleware.  If that's not set up correctly, then calling
           run after adding a callback will raise a RuntimeError.
 

dramatiq/middleware/group_callbacks.py

@@ -26,6 +26,8 @@
 
 
 class GroupCallbacks(Middleware):
+    """Middleware that enables adding completion callbacks to |Groups|."""
+
     def __init__(self, rate_limiter_backend: RateLimiterBackend) -> None:
         self.rate_limiter_backend = rate_limiter_backend