Comment 29 for bug 1664294

Reviewed: https://review.openstack.org/458435
Committed: https://git.openstack.org/cgit/openstack/neutron-fwaas/commit/?id=a08e30539a34f8ec20ab807ea1630d99d7adfb4e
Submitter: Jenkins
Branch: stable/ocata

commit a08e30539a34f8ec20ab807ea1630d99d7adfb4e
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 14 13:36:02 2017 +0100

    Define in_namespace contextmanager

    This change defines the contextmanager in_namespace[1]. It moves current
    process in a network namespace (in __enter__) and moves it back in its
    original network namespace (in _exit__) or kills current process if
    __exit__ fails in order to ensure following commands will be executed
    in the correct network namespace.

    This change is an enabler to the Netlink solution to clean conntrack
    entries.

    [1] neutron_fwaas.privileged.utils

    Partial-Bug: #1664294
    Change-Id: I587257db8e1fce56a95f0db3dc4e0752751fdd81
    (cherry picked from commit 094d2d5f01914fbebd4e16cc2c41390a72b5874d)