Deprecate the dramatiq_group_callback_barrier_ttl environment variable (#775)

* Deprecate the `dramatiq_group_callback_barrier_ttl` environment variable
* Use the new `barrier_ttl` argument instead

#775

---------

Co-authored-by: LincolnPuzey <18750802+LincolnPuzey@users.noreply.github.com>

Author: mikeroll

docs/source/reference.rst

@@ -293,7 +293,7 @@ These are the environment variables that dramatiq reads
      - The maximum amount of time a message can be in the dead letter queue for the RabbitMQ Broker (in milliseconds).
    * - ``dramatiq_group_callback_barrier_ttl``
      - 86400000 (One day)
-     -
+     - Deprecated. Use the `barrier_ttl` parameter of |GroupCallbacks| middleware instead.
    * - ``dramatiq_prom_db``
      - tempfile.gettempdir()/dramatiq-prometheus
      - The path to store the prometheus database files. See :ref:`gotchas-with-prometheus`.

dramatiq/composition.py

@@ -266,15 +266,12 @@ def run(self, *, delay=None):
           group: This same group.
         """
         if self.completion_callbacks:
-            from .middleware.group_callbacks import (
-                GROUP_CALLBACK_BARRIER_TTL,
-                GroupCallbacks,
-            )
+            from .middleware.group_callbacks import GroupCallbacks
 
-            rate_limiter_backend = None
             for middleware in self.broker.middleware:
                 if isinstance(middleware, GroupCallbacks):
                     rate_limiter_backend = middleware.rate_limiter_backend
+                    barrier_ttl = middleware.barrier_ttl
                     break
             else:
                 raise RuntimeError(
@@ -287,7 +284,7 @@ def run(self, *, delay=None):
             # group is re-run, the barriers are all separate.
             # Re-using a barrier's name is an unsafe operation.
             completion_uuid = str(uuid4())
-            completion_barrier = Barrier(rate_limiter_backend, completion_uuid, ttl=GROUP_CALLBACK_BARRIER_TTL)
+            completion_barrier = Barrier(rate_limiter_backend, completion_uuid, ttl=barrier_ttl)
             completion_barrier.create(len(self.children))
 
             children = []

dramatiq/middleware/group_callbacks.py

@@ -18,19 +18,30 @@
 from __future__ import annotations
 
 import os
+import warnings
 
 from ..rate_limits import Barrier, RateLimiterBackend
 from .middleware import Middleware
 
-GROUP_CALLBACK_BARRIER_TTL = int(os.getenv("dramatiq_group_callback_barrier_ttl", "86400000"))
-
 
 class GroupCallbacks(Middleware):
     """Middleware that enables adding completion callbacks to |Groups|."""
 
-    def __init__(self, rate_limiter_backend: RateLimiterBackend) -> None:
+    def __init__(self, rate_limiter_backend: RateLimiterBackend, *, barrier_ttl: int = 86400 * 1000) -> None:
         self.rate_limiter_backend = rate_limiter_backend
 
+        _barrier_ttl_env = os.getenv("dramatiq_group_callback_barrier_ttl", None)
+        if _barrier_ttl_env is not None:
+            warnings.warn(
+                "Configuring the barrier TTL via the 'dramatiq_group_callback_barrier_ttl' environment variable is deprecated; "
+                "use the `barrier_ttl` argument of the `GroupCallbacks` middleware instead.",
+                FutureWarning,
+                stacklevel=2,
+            )
+            self.barrier_ttl = int(_barrier_ttl_env)
+        else:
+            self.barrier_ttl = barrier_ttl
+
     def after_process_message(self, broker, message, *, result=None, exception=None):
         from ..message import Message
 
@@ -41,7 +52,7 @@ def after_process_message(self, broker, message, *, result=None, exception=None)
                 barrier = Barrier(
                     self.rate_limiter_backend,
                     group_completion_uuid,
-                    ttl=GROUP_CALLBACK_BARRIER_TTL,
+                    ttl=self.barrier_ttl,
                 )
                 if barrier.wait(block=False):
                     for message in group_completion_callbacks: