Leaking resources by incorrect use of `open_environment`

[Jun Omae]

Original issue at ​trac:#11139.

The following error is caused by incorrect use of open_environment.

OSError: [Errno 24] Too many open files: '/opt/trac'

open_environment without use_cache creates every time a new instance of Environment. However, TicketMoverPlugin doesn't release nor cache. Therefore, some resources leak.

ticketmoverplugin/ticketmover.py

@@ -155 +155 @@
         for project in _projects:
             path = os.path.join(base_path, project)
             try:
-                env = open_environment(path)
+                env = open_environment(path, use_cache=True)
             except:
                 continue
             perm = PermissionSystem(env)
@@ -176 +176 @@
         # open the environment if it is a string
         if isinstance(env, basestring):
             base_path, _project = os.path.split(self.env.path)
-            env = open_environment(os.path.join(base_path, env))
+            env = open_environment(os.path.join(base_path, env), use_cache=True)
 
         # get the old ticket
         old_ticket = Ticket(self.env, ticket_id)

[Ryan J Ollos]

jun66j5: k0s is no longer active in the Trac community and has given permission for his plugins to be adopted, so feel free to push the patch directly to the repository.

[Jun Omae]

(In [12863]) TicketMoverPlugin: fix #11000: leaking resources caused by open_environment

[Ryan J Ollos]

jun66j5: #11091 reports a significant slowdown when using this plugin. We aren't sure yet which version is being used, but do you think the issue you fixed here could be the cause?

[Jun Omae]

Yes. I think that the slowdown in #11091 has been fixed by [12863].

Before the changes, Trac constructs all tracenvs using open_environment on every request while viewing ticket page. After the changes, Trac uses Environment instances in the cache.