How can you force a memory limit in Django WSGI apps?

Question

I want my app to throw an MemoryError when its usage goes over 1GB. I'm running in WSGI daemon mode.

I see 3 places the memory limit could be:

• apache.conf
• wsgi somewhere
• django configuration

but I can't find the right config options. In PHP you can do this with :

php_value memory_limit 1GB

in your apache.conf

Answer 1

Resource memory limits aren't implemented on most platforms even though C API definitions exist. As such, mod_wsgi doesn't try to implement such restrictions. If PHP is doing it, is is able to do so by virtue that that it is a more constrained and controlled environment than Python.

The only portable way is to have a separate daemon process running which runs 'ps' or uses '/proc' to monitor memory usage of processes and then send a SIGINT signal to those which go over some predefined value.

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UPDATE

Version 3.4 of mod_wsgi supports options for daemon mode that may be able to restrict memory usage. See:

• http://code.google.com/p/modwsgi/wiki/ChangesInVersion0304

Whether they work depends on the operating system you are using.

Answer 2

Use resource.setrlimit() with resource.RLIMIT_VMEM.