💥 Enable lambda worker async configure callback (#1604)

* 💥 enable lambda worker async configure

* example adjustment

* comment updates

* update changelog

Author: jmaeagle99

CHANGELOG.md

@@ -19,6 +19,19 @@ to docs, or any other relevant information.
 
 ## [Unreleased]
 
+### Changed
+
+- AWS Lambda worker `configure` parameter supports sync, async, and async
+  generator style functions. This callback is invoked on the asyncio event
+  loop.
+
+### Breaking Changes
+
+- AWS Lambda worker `configure` parameter has been changed to be invoked
+  per-invocation of the worker instead of only at startup. It is advised that
+  any shared, heavy-weight operations are performed outside of the callback
+  before `run_worker` is invoked.
+
 ## [1.29.0] - 2026-06-17
 
 ### Added

temporalio/contrib/aws/lambda_worker/README.md

@@ -48,6 +48,24 @@ pre-populated with Lambda-appropriate defaults. Override any field directly in
 the callback. The `task_queue` key in `worker_config` is pre-populated from the
 `TEMPORAL_TASK_QUEUE` environment variable if set.
 
+### Sync, async, and async-generator configure
+
+The configure callback runs **once per invocation, inside that invocation's
+event loop**, before the client connects. It may be:
+
+- a plain function `def configure(config) -> None`;
+- an `async def configure(config) -> None` coroutine — awaited for setup (pair
+  with `shutdown_hooks` for teardown);
+- an `async def configure(config): ...; yield; ...` async generator — statements
+  before the single `yield` run before the client connects, the worker runs
+  while the generator is suspended at the `yield`, and statements after the
+  `yield` run as teardown once the worker has stopped.
+
+The callback runs per invocation (rather than once at process start) because
+event-loop-bound resources cannot be created before an event loop exists and
+cannot be shared across invocations — each invocation runs under a fresh
+`asyncio.run` loop.
+
 ## Lambda-tuned worker defaults
 
 The package applies conservative concurrency limits suited to Lambda's resource