Trigger gevent monkeypatching via environment variable

airflow/__init__.py

@@ -32,6 +32,14 @@
 import sys
 from typing import Callable
 
+if os.environ.get("_AIRFLOW_PATCH_GEVENT"):
+    # If you are using gevents and start airflow webserver, you might want to run gevent monkeypatching
+    # as one of the first thing when Airflow is started. This allows gevent to patch networking and other
+    # system libraries to make them gevent-compatible before anything else patches them (for example boto)
+    from gevent.monkey import patch_all
+
+    patch_all()
+
 from airflow import settings
 
 __all__ = ["__version__", "login", "DAG", "PY36", "PY37", "PY38", "PY39", "PY310", "XComArg"]
@@ -41,6 +49,7 @@
 # lib.)
 __path__ = __import__("pkgutil").extend_path(__path__, __name__)  # type: ignore
 
+
 # Perform side-effects unless someone has explicitly opted out before import
 # WARNING: DO NOT USE THIS UNLESS YOU REALLY KNOW WHAT YOU'RE DOING.
 if not os.environ.get("_AIRFLOW__AS_LIBRARY", None):

airflow/config_templates/config.yml

@@ -1233,7 +1233,9 @@
     - name: worker_class
       description: |
         The worker class gunicorn should use. Choices include
-        sync (default), eventlet, gevent
+        sync (default), eventlet, gevent. Note when using gevent you might also want to set the
+        "_AIRFLOW_PATCH_GEVENT" environment variable to "1" to make sure gevent patching is done as
+        early as possible.
       version_added: ~
       type: string
       example: ~

airflow/config_templates/default_airflow.cfg

@@ -640,7 +640,9 @@ secret_key = {SECRET_KEY}
 workers = 4
 
 # The worker class gunicorn should use. Choices include
-# sync (default), eventlet, gevent
+# sync (default), eventlet, gevent. Note when using gevent you might also want to set the
+# "_AIRFLOW_PATCH_GEVENT" environment variable to "1" to make sure gevent patching is done as
+# early as possible.
 worker_class = sync
 
 # Log files for the gunicorn webserver. '-' means log to stderr.

newsfragments/08212.misc.rst

@@ -0,0 +1 @@
+If you are using gevent for your webserver deployment and used local settings to monkeypatch gevent, you might want to replace local settings patching with an ``_AIRFLOW_PATCH_GEVENT`` environment variable set to 1 in your webserver. This ensures gevent patching is done as early as possible.