Fix cache invalidation on clear command

[bottleneko]

Hello!

I'm getting problem with announce new routes to neighbours from config after clear command.

Routes will announced only to one neighbour but after restart or withdraw command on each route, exabgp will annonce routes to both neighbours

My config is:

process tcp-control-server {
    run ./exabgp-tcp-server.py /etc/exabgp/exabgp.env;
    encoder text;
}

template {
    neighbor common {
        router-id 10.0.0.1;
        local-address 10.0.0.1;

        local-as 65533;

        peer-as 65100;
    }
}

neighbor 10.0.1.1 { inherit common; }
neighbor 10.0.2.1 { inherit common; }

Steps to reproduce:

1. Send announce commands to exabgp

announce route 10.0.3.1 next-hop self
announce route 10.0.4.1 next-hop self

After that

$ exabgpcli show adj-rib out
neighbor 10.0.1.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.1.1 ipv4 unicast 10.0.4.1/32 next-hop self
neighbor 10.0.2.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.2.1 ipv4 unicast 10.0.4.1/32 next-hop self

2. Send clear command to exabgp clear adj-rib out

$ exabgpcli show adj-rib out
neighbor 10.0.1.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.1.1 ipv4 unicast 10.0.4.1/32 next-hop self
neighbor 10.0.2.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.2.1 ipv4 unicast 10.0.4.1/32 next-hop self

3. Send announce commands to exabgp

announce route 10.0.3.1 next-hop self
announce route 10.0.4.1 next-hop self

After that

$ exabgpcli show adj-rib out
neighbor 10.0.1.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.1.1 ipv4 unicast 10.0.4.1/32 next-hop self

4. Restart exabgp systemctl restart exabgp

$ exabgpcli show adj-rib out
neighbor 10.0.1.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.1.1 ipv4 unicast 10.0.4.1/32 next-hop self
neighbor 10.0.2.1 ipv4 unicast 10.0.3.1/32 next-hop self
neighbor 10.0.2.1 ipv4 unicast 10.0.4.1/32 next-hop self

This problem caused by withdrawing all announces in https://github.com/Exa-Networks/exabgp/blob/master/lib/exabgp/rib/outgoing.py#L92. Cached changes consist withdrew changes but they will not be invalidated because generator produces only announced changes from cache.

[thomas-mangin]

Thank you very much for this fix :-) Much appreciated.

[thomas-mangin]

Could I ask you if you port this patch to branch 4.2 .. Sorry for being cheeky her but it would save me doing it and 5.0.0 is currently in flux so the fix should make it to the stable branch too.
Also you could use the occasion to add an entry to the CHANGELOG.rst too :-)

[bottleneko]

Thanks you very much for fast merge :)

May you make release with this fix on current master or backport this changes into previous supported releases, please?

[bottleneko]

Could I ask you if you port this patch to branch 4.2 .. Sorry for being cheeky her but it would save me doing it and 5.0.0 is currently in flux so the fix should make it to the stable branch too.
Also you could use the occasion to add an entry to the CHANGELOG.rst too :-)

Yes, of course, now I will make additional changes :)

[thomas-mangin]

@bottleneko 4.2.10 released just for you 😉

[bottleneko]

@thomas-mangin thanks you very much :)