fix(tracer): fix multiprocessing queue on aws lambda [backport 2.2] (#…

…7692)

Backport 1656e7d from #7612 to 2.2.

#6929 introduced a bug as
multiprocessing.Queue is not supported on AWS lambda platform.
This fix prevents the use of the Queue on aws lambda, as this is used
for a RC only feature, and lambda does not use RC.

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [x] Title is accurate.
- [x] No unnecessary changes are introduced.
- [x] Description motivates each change.
- [x] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [x] Testing strategy adequately addresses listed risk(s).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] Release note makes sense to a user of the library.
- [x] Reviewer has explicitly acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment.
- [x] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)
- [x] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [x] This PR doesn't touch any of that.

Co-authored-by: Christophe Papazian <114495376+christophe-papazian@users.noreply.github.com>

ddtrace/settings/config.py

@@ -28,6 +28,7 @@
 from ..internal.constants import PROPAGATION_STYLE_B3_SINGLE
 from ..internal.logger import get_logger
 from ..internal.schema import DEFAULT_SPAN_SERVICE_NAME
+from ..internal.serverless import in_aws_lambda
 from ..internal.utils.formats import asbool
 from ..internal.utils.formats import parse_tags_str
 from ..pin import Pin
@@ -264,9 +265,11 @@ class Config(object):
     available and can be updated by users.
     """
 
-    _extra_services_queue = multiprocessing.get_context("fork" if sys.platform != "win32" else "spawn").Queue(
-        512
-    )  # type: multiprocessing.Queue
+    _extra_services_queue = (
+        None
+        if in_aws_lambda()
+        else multiprocessing.get_context("fork" if sys.platform != "win32" else "spawn").Queue(512)
+    )  # type: multiprocessing.Queue | None
 
     class _HTTPServerConfig(object):
         _error_statuses = "500-599"  # type: str
@@ -486,6 +489,8 @@ def __getattr__(self, name):
         return self._integration_configs[name]
 
     def _add_extra_service(self, service_name: str) -> None:
+        if self._extra_services_queue is None:
+            return
         if self._remote_config_enabled and service_name != self.service:
             try:
                 self._extra_services_queue.put_nowait(service_name)
@@ -494,7 +499,8 @@ def _add_extra_service(self, service_name: str) -> None:
 
     def _get_extra_services(self):
         # type: () -> set[str]
-
+        if self._extra_services_queue is None:
+            return set()
         try:
             while True:
                 self._extra_services.add(self._extra_services_queue.get(timeout=0.002))

scripts/releasenotes/notes/do-not-use-multiprocessing-queue-in-aws-lambda-99fd75820125906f.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    lambda: This change disables the use of ``multiprocessing.queue`` in Lambda, because it is not supported in Lambda