issue2551212 - enable wsgi cache_tracker by default

Switch the code so the wsgi cache_tracker optimization is enabled by
default. Leave the unoptimized/uncached code path available in case it
breaks something.  The feature flag can be set to False to disable
caching.

Updated tests to test the disabled (non-cache) code path.

Updated upgrading.txt with info on how to disable caching.

Author: rouilj

CHANGES.txt

@@ -143,7 +143,9 @@ Features:
   machine parsible output. (John Rouillard)
 - Multiple JWT secrets are supported to allow key rotation. See
   an updated config.ini for details. (John Rouillard)
-
+- issue2551212 - wsgi performance improvement feature added in 2.2.0
+  is active by default. Can be turned off if needed. See upgrading.txt
+  for info. (John Rouillard)
 
 2023-07-13 2.3.0
 

doc/upgrading.txt

@@ -112,6 +112,24 @@ values or if a value must be changed manually.
 
 This will insert the bad API login rate limiting settings.
 
+Disable performance improvement for wsgi mode (optional)
+--------------------------------------------------------
+
+In Roundup version 2.2.0 an experimental option to improve performance
+when running in wsgi mode was added. It as disabled at that time. In
+the last two years it has been in use at a few sits with no reports of
+issues.
+
+So the default mode is now to enable this improvement. This will get
+more people using it. In case there is a latent bug that hasn't been
+discovered, it can still be disabled. To disable it, add the
+feature_flags to the RequestDispatcher as below:
+
+   feature_flags = { "cache_tracker": False }
+   app =  RequestDispatcher(tracker_home, feature_flags=feature_flags)
+
+and restart your wsgi instance.
+
 Fix duplicate id for confirm password in user.item.html (optional)
 ------------------------------------------------------------------
 

roundup/cgi/wsgi_handler.py

@@ -98,7 +98,8 @@ def __init__(self, home, debug=False, timing=False, lang=None,
         else:
             self.translator = None
 
-        if "cache_tracker" in self.feature_flags:
+        if "cache_tracker" not in self.feature_flags or \
+           self.feature_flags["cache_tracker"] is not False:
             self.tracker = roundup.instance.open(self.home, not self.debug)
         else:
             self.preload()
@@ -133,7 +134,8 @@ def __call__(self, environ, start_response):
         else:
             form = BinaryFieldStorage(fp=environ['wsgi.input'], environ=environ)
 
-        if "cache_tracker" in self.feature_flags:
+        if "cache_tracker" not in self.feature_flags or \
+           self.feature_flags["cache_tracker"] is not False:
             client = self.tracker.Client(self.tracker, request, environ, form,
                                          self.translator)
             try:

test/test_liveserver.py

@@ -127,7 +127,9 @@ def teardown_class(cls):
         i18n.DOMAIN = cls.backup_domain
 
     def create_app(self):
-        '''The wsgi app to start - no feature_flags set.'''
+        '''The wsgi app to start - no feature_flags set.
+           Post 2.3.0 this enables the cache_tracker feature.
+        '''
 
         if _py3:
             return validator(RequestDispatcher(self.dirname))
@@ -1215,13 +1217,13 @@ def test_fts(self):
         f = requests.get(self.url_base() + "?@search_text=RESULT")
         self.assertIn("foo bar", f.text)
 
-class TestFeatureFlagCacheTrackerOn(BaseTestCases, WsgiSetup):
+class TestFeatureFlagCacheTrackerOff(BaseTestCases, WsgiSetup):
     """Class to run all test in BaseTestCases with the cache_tracker
-       feature flag enabled when starting the wsgi server
+       feature flag disabled when starting the wsgi server
     """
     def create_app(self):
-        '''The wsgi app to start with feature flag enabled'''
-        ff = { "cache_tracker": "" }
+        '''The wsgi app to start with feature flag disabled'''
+        ff = { "cache_tracker": False }
         if _py3:
             return validator(RequestDispatcher(self.dirname, feature_flags=ff))
         else:
@@ -1232,7 +1234,7 @@ def create_app(self):
 @skip_postgresql
 class TestPostgresWsgiServer(BaseTestCases, WsgiSetup):
     """Class to run all test in BaseTestCases with the cache_tracker
-       feature flag enabled when starting the wsgi server
+       feature enabled when starting the wsgi server
     """
 
     backend = 'postgresql'