ref(metrics): Deprecate sentry_sdk.metrics (#3512)

Raise a `DeprecationWarning` on import of the `sentry_sdk.metrics` module.

Closes #3502

Author: szokeasaurusrex

sentry_sdk/metrics.py

@@ -5,6 +5,7 @@
 import sys
 import threading
 import time
+import warnings
 import zlib
 from abc import ABC, abstractmethod
 from contextlib import contextmanager
@@ -54,6 +55,14 @@
     from sentry_sdk._types import MetricValue
 
 
+warnings.warn(
+    "The sentry_sdk.metrics module is deprecated and will be removed in the next major release. "
+    "Sentry will reject all metrics sent after October 7, 2024. "
+    "Learn more: https://sentry.zendesk.com/hc/en-us/articles/26369339769883-Upcoming-API-Changes-to-Metrics",
+    DeprecationWarning,
+    stacklevel=2,
+)
+
 _in_metrics = ContextVar("in_metrics", default=False)
 _set = set  # set is shadowed below
 

sentry_sdk/tracing.py

@@ -1298,4 +1298,8 @@ async def my_async_function():
     has_tracing_enabled,
     maybe_create_breadcrumbs_from_span,
 )
-from sentry_sdk.metrics import LocalAggregator
+
+with warnings.catch_warnings():
+    # The code in this file which uses `LocalAggregator` is only called from the deprecated `metrics` module.
+    warnings.simplefilter("ignore", DeprecationWarning)
+    from sentry_sdk.metrics import LocalAggregator