Ensure DeprecationWarning is ignored when setting up logging

closes #2004
https://pulp.plan.io/issues/2004

server/pulp/server/logs.py

@@ -6,6 +6,7 @@
 import os
 import sys
 import threading
+import warnings
 
 from celery.signals import setup_logging
 
@@ -41,6 +42,11 @@ def start_logging(*args, **kwargs):
     :param kwargs: Unused
     :type  kwargs: dict
     """
+    # Filter out all deprecation warnings before setting up the logger,
+    # unless user-specified warning settings are passed using '-W'.
+    if not sys.warnoptions:
+        warnings.simplefilter('ignore', DeprecationWarning)
+
     # Get and set up the root logger with our configured log level
     try:
         log_level = config.config.get('server', 'log_level')

server/test/unit/server/test_logs.py

@@ -12,6 +12,7 @@
 import threading
 import traceback
 import unittest
+import warnings
 
 import mock
 
@@ -687,6 +688,15 @@ def test_calls__blacklist_loggers(self, getLogger, get, _blacklist_loggers):
 
         _blacklist_loggers.assert_called_once_with()
 
+    @mock.patch('pulp.server.logs.warnings')
+    def test_calls_simplefilter(self, _warnings):
+        """
+        Ensure that start_logging() calls warnings.simplefilter
+        """
+        logs.start_logging()
+
+        _warnings.simplefilter.assert_called_once_with("ignore", DeprecationWarning)
+
     @mock.patch('pulp.server.logs.logging')
     def test_calls__captureWarnings(self, _logging):
         """
@@ -812,6 +822,24 @@ def fake_getLogger(name=None):
         # And the handler should have the formatter with our format string
         self.assertEqual(root_handler.formatter._fmt, logs.LOG_FORMAT_STRING)
 
+    def test_deprecation_warnings_suppressed(self):
+        with warnings.catch_warnings(record=True) as recorded_warnings:
+            # reset warnings filter to include DeprecationWarnings
+            #  https://docs.python.org/2/library/warnings.html#updating-code-for-new-versions-of-python
+            warnings.simplefilter('default')
+
+            # this warning should be emitted and caught prior to calling start_logging
+            warnings.warn("caught", DeprecationWarning)
+
+            logs.start_logging()
+
+            # this warning should be emitted and ignored after calling start_logging
+            warnings.warn("ignored", DeprecationWarning)
+
+        # Only one warning was caught, and it's the one that was expected.
+        self.assertEqual(len(recorded_warnings), 1)
+        self.assertEqual(repr(recorded_warnings[0].message), repr(DeprecationWarning("caught")))
+
 
 class TestStopLogging(unittest.TestCase):
     """