Gossipsub – subscriptions not propagated?

[Wiezzel]

I'm running three nodes, let's call them bootnode, subscriber, and publisher. They use the following network behaviours: identify, kademlia, and gossipsub. Both subscriber and publisher connect to the bootnode and do a kademlia bootstrap.

graph TD;
    subscriber-->bootnode;
    publisher-->bootnode;

Loading

Then, subscriber subscribes to a gossipsub topic, and publisher starts publishing some messages on this topic. The problem is that messages are delivered only if subscriber is started after publisher. So it seems as if existing subscriptions are not propagated to a new node joining the network. Is this an expected behaviour or a bug? What could be a workaround for this?

[mxinden]

The problem is that messages are delivered only if subscriber is started after publisher.

This seems like a bug to me.

Is the bootnode subscribed to the topic?

So it seems as if existing subscriptions are not propagated to a new node joining the network.

I don't think subscriptions are intended to be gossiped. In other words, I don't think subscription events go further than one hop.

Is this an expected behaviour or a bug? What could be a workaround for this?

Are you able to create a small reproducer or even better write a small test that fails?

See https://github.com/libp2p/rust-libp2p/blob/master/protocols/gossipsub/tests/smoke.rs on how to write a gossipsub test.

[Wiezzel]

Is the bootnode subscribed to the topic?

No, it is not.

I'll try to create a minimum reproducible example and share it.

[Wiezzel]

When I tried to build a minimal reproducible example, I couldn't reproduce the issue. So I got back to my original code and discovered that the problem doesn't occur if I wait 5s before starting publisher. Originally, publisher and subscriber connected to the bootnode roughly at the same time. Must be some kind of race condition. 🤔

[dariusc93]

can you run it with RUST_LOG=libp2p_gossipsub=trace and produce a log? Also could you provide any configurations, etc?

[Wiezzel]

@dariusc93 I'll try to prepare a minimal docker-compose setup with 3 nodes and share it.

[thomaseizinger]

Possibly related: #3216.