On Wed, Jul 11, 2018 at 2:08 AM Ben Pfaff <b...@ovn.org> wrote: > On Wed, Jul 11, 2018 at 12:56:39AM +0530, nusid...@redhat.com wrote: > > From: Numan Siddique <nusid...@redhat.com> > > > > The python function ovs.socket_util.check_connection_completion() uses > select() > > (provided by python) to monitor the socket file descriptor. The select() > > returns 1 when the file descriptor becomes ready. For error cases like - > > 111 (Connection refused) and 113 (No route to host) (POLLERR), > ovs.poller._SelectSelect.poll() > > expects the exceptfds list to be set by select(). But that is not the > case. > > As per the select() man page, writefds list will be set for POLLERR. > > Please see "Correspondence between select() and poll() notifications" > section of select(2) > > man page. > > > > Because of this behavior, ovs.socket_util.check_connection_completion() > returns success > > even if the remote is unreachable or not listening on the port. > > > > This patch fixes this issue by adding a wrapper function - > check_connection_completion_status() > > which calls sock.connect_ex() to get the status of the connection if > > ovs.socket_util.check_connection_completion() returns success. > > > > The test cases added fails without the fix in this patch. > > > > Signed-off-by: Numan Siddique <nusid...@redhat.com> > > Can we just code check_connection_completion() like we do in C, by > directly using select() on Windows and poll() everywhere else? The > approach in this patch seems a little indirect to me. > > Thanks for the review. As per the comments here - https://github.com/openvswitch/ovs/blob/master/python/ovs/poller.py#L51 ***** # eventlet/gevent doesn't support select.poll. If select.poll is used, # python interpreter is blocked as a whole instead of switching from the # current thread that is about to block to other runnable thread. # So emulate select.poll by select.select because using python means that # performance isn't so important. *******
we cannot use poll() in python. I tried with this patch to test it out - https://paste.fedoraproject.org/paste/YUhgVte-BOjgid-ojmHZJw All the ovs python idl tests pass. But it doesn't work with openstack networking-ovn. The whole neutron-server process just blocks. I don't see any other way for python. Once select() returns we have to use some mechanism to get the error code. Does calling sock.connect_ex() bother you ? Thanks Numan > Thanks, > > Ben. > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
