deprecate eventlet monkey patch within lockutils

Change-Id: I83352849192489e6918898969b92ee3f8e2bca55

oslo_concurrency/lockutils.py

@@ -25,6 +25,7 @@ import tempfile
 import threading
 import weakref
 
+import debtcollector
 import fasteners
 from oslo_config import cfg
 from oslo_utils import reflection
@@ -98,6 +99,8 @@ class ReaderWriterLock(fasteners.ReaderWriterLock):
         # environment
         if eventlet is not None and eventlet_patcher is not None:
             if eventlet_patcher.is_monkey_patched('thread'):
+                debtcollector.deprecate(
+                    "Eventlet support is deprecated and will be removed.")
                 self._current_thread = eventlet.getcurrent
 
 

releasenotes/notes/deprecate-eventlet-within-lockutils-cba49086d7a65042.yaml

@@ -0,0 +1,11 @@
+---
+deprecations:
+  - |
+    Eventlet usages are deprecated and the removal of Eventlet from
+    OpenStack `is planned <https://governance.openstack.org/tc//goals/proposed/remove-eventlet.html>`_,
+    for this reason, using the ``lockutils`` module of oslo.concurrency in a
+    monkey patched environment is now deprecated. The support of Eventlet will
+    be soon removed from oslo.concurrency.
+
+    Please start considering removing your internal Eventlet usages and
+    start migrating your stack.

requirements.txt

@@ -7,3 +7,4 @@ oslo.config>=5.2.0 # Apache-2.0
 oslo.i18n>=3.15.3 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
 fasteners>=0.7.0 # Apache-2.0
+debtcollector>=3.0.0 # Apache-2.0