Import eventlet conditionally

Import eventlet conditionally to avoid extra noise
in logs where we don't need eventlet anyway.

Change-Id: Idcb56e02eff328ffe60de251ff694fcdc7d017f1
Signed-off-by: lajoskatona <lajos.katona@est.tech>

oslo_rootwrap/__init__.py

@@ -14,6 +14,7 @@
 #    under the License.
 
 import os
+import sys
 
 import debtcollector
 
@@ -21,11 +22,11 @@ __all__ = [
     'subprocess',
 ]
 
-try:
+_patched_socket = False
+
+if 'eventlet' in sys.modules:
     import eventlet.patcher
-except ImportError:
-    _patched_socket = False
-else:
+
     # In tests patching happens later, so we'll rely on environment variable
     _patched_socket = eventlet.patcher.is_monkey_patched('socket') or bool(
         os.environ.get('TEST_EVENTLET', False)

oslo_rootwrap/tests/test_functional_eventlet.py

@@ -20,6 +20,13 @@ if os.environ.get('TEST_EVENTLET', False):
 
     eventlet.monkey_patch()
 
+    import oslo_rootwrap
+
+    oslo_rootwrap._patched_socket = True
+    from eventlet.green import subprocess
+
+    oslo_rootwrap.subprocess = subprocess
+
     from oslo_rootwrap.tests import test_functional
 
     class RootwrapDaemonTest(test_functional.RootwrapDaemonTest):