feat: add importlib metadata default on flask module

CHANGELOG.md

@@ -10,11 +10,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - `opentelemetry-instrumentation-celery` Allow Celery instrumentation to be installed multiple times
   ([#2342](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2342))
-- Align gRPC span status codes to OTEL specification ([#1756](https://github.com/open-telemetry/opentelemetry-python-contrib/issues/1756))
+- Align gRPC span status codes to OTEL specification
+  ([#1756](https://github.com/open-telemetry/opentelemetry-python-contrib/issues/1756))
+- `opentelemetry-instrumentation-flask` Add importlib metadata default for deprecation warning flask version
+  ([#2297](https://github.com/open-telemetry/opentelemetry-python-contrib/issues/2297))
 
 ## Version 1.23.0/0.44b0 (2024-02-23)
 
-- Drop support for 3.7
+- Drop uspport for 3.7
   ([#2151](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2151))
 - `opentelemetry-resource-detector-azure` Added 10s timeout to VM Resource Detector
   ([#2119](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2119))

instrumentation/opentelemetry-instrumentation-flask/pyproject.toml

@@ -30,6 +30,7 @@ dependencies = [
   "opentelemetry-semantic-conventions == 0.45b0.dev",
   "opentelemetry-util-http == 0.45b0.dev",
   "packaging >= 21.0",
+  "importlib-metadata >= 4.0",
 ]
 
 [project.optional-dependencies]

instrumentation/opentelemetry-instrumentation-flask/src/opentelemetry/instrumentation/flask/__init__.py

@@ -245,22 +245,13 @@ def response_hook(span: Span, status: str, response_headers: List):
 from typing import Collection
 
 import flask
+import importlib_metadata as metadata
 from packaging import version as package_version
 
 import opentelemetry.instrumentation.wsgi as otel_wsgi
 from opentelemetry import context, trace
 from opentelemetry.instrumentation.flask.package import _instruments
 from opentelemetry.instrumentation.flask.version import __version__
-
-try:
-    flask_version = flask.__version__
-except AttributeError:
-    try:
-        from importlib import metadata
-    except ImportError:
-        import importlib_metadata as metadata
-    flask_version = metadata.version("flask")
-
 from opentelemetry.instrumentation.instrumentor import BaseInstrumentor
 from opentelemetry.instrumentation.propagators import (
     get_global_response_propagator,
@@ -281,6 +272,8 @@ def response_hook(span: Span, status: str, response_headers: List):
 
 _excluded_urls_from_env = get_excluded_urls("FLASK")
 
+flask_version = metadata.version("flask")
+
 if package_version.parse(flask_version) >= package_version.parse("2.2.0"):
 
     def _request_ctx_ref() -> weakref.ReferenceType: