Watch EOR grpc method

[bayrinat]

Add new EOR type for WatchEvent method.
It provides opportunity of getting 'readiness' of the current peer.

[bayrinat]

@fujita what do you think?

[bayrinat]

@fujita gentle ping.

[fujita]

Sorry about the delay. why you don't use TableEvent?

[bayrinat]

Sorry about the delay. why you don't use TableEvent?

Thanks for replying.
Could you please explain the reasons? Is the TableEvent a decent type?

I mean EOR-method signals that all eor messages from peers are received. It corresponds with table and peers as well.
If I add it to TableEvent or to PeerEvent, it will be confusing a little bit.

[fujita]

I thought that simply EoR messages can be sent via TableEvent.Paths. But you prefer to know when a peer gets EoR messages in all families? If so, the proposal looks like reasonable.

[bayrinat]

Actually, I like your idea to watch each eor message via Paths. It will be even more useful, will be come soon with implementation.

[bayrinat]

I've tried to make it at least minimalistic as possible.

[bayrinat]

@fujita What do you think about this PR?

[fujita]

Is this necessary? ADJIN is supposed to send all messages include EoR?

[bayrinat]

Is this necessary? ADJIN is supposed to send all messages include EoR?

Adding a new filter provides opportunity of getting eor message itself without handling adj-in tables that can be huge.
I thought about adding it to Best actually, but it will probably not the right place (tell me if I'm wrong).

[fujita]

I see. Is this backward compatible?

[bayrinat]

It looks so. If you don't add a filter, you won't get an eor message.

[fujita]

The old binary (using Watch gRPC API) works with the gobgpd binary including this change?

[mai2412]

I would really like this feature as well (unless there was another way of watching EOR). Would you recommend opening a new pr or is it possible to merge this? @fujita @bayrinat

[fujita]

If someone confirms that this change doesn't break the backward compatibility of the gRPC API, then I'll merge.

[mai2412]

Tested that:
$ gobgp monitor global rib / adj-in / neighbor
works with the gobgpd built from this change.

[fujita]

@mai2412 After reading the latest code, I guess that watchEventUpdate enables you to monitor EOR.

[mai2412]

@fujita Ahh I see that the POST_POLICY filter has to be used, I did not see this before and only tried testing with BEST and ADJIN. It would be ideal if there's a filter for getting just the EOR message without the other updates. I think the original proposal of this PR that introduces a new message type EOR might also work well. What do you think?

Do correct me if i said anything wrong, thank you for looking into this.

[bayrinat]

At last I rebased the code with some minor changes.

• This change still doesn't break the backward compatibility and works stable.

[bayrinat]

@fujita gentle ping

[fujita]

Pushed, thanks.