functools.lru caches fds

test.py

import os
import sys
import traceback
import pyroute2.netns
i = 0

import functools

@functools.lru_cache(maxsize=1024)
def get_fd_from_netnspath(netnspath):
    return os.open(netnspath, os.O_RDONLY)

while True:
    try:
        pyroute2.netns.setns(get_fd_from_netnspath('/proc/1/ns/net'))
    except:
        traceback.print_exc(file=sys.stderr)
        print(i)
        break
    i += 1