How to handle multiple channels

[bnjjj]

Hello, I will explain my need, indeed I'm trying to move from a homemade solution with tokio TcpStream to a libp2p implementation. For now I have 2 opened tcp stream in my solution with 2 different ports. One to send specific events and another one to send commands. I'm wondering what is the best way to handle this kind of multiple channels thanks to libp2p. I saw yamux, I saw mplex, I read about multiplexing but I'm a little bit lost. Knowing that each nodes could send or receive data on these 2 channels.

Thanks for your help

[thomaseizinger]

For libp2p you will want to think in protocols.

As an intermediary transition, you can make two protocols (implying two NetworkBehaviours in the end), one for events and one for commands.

Likely, as you learn more about libp2p, you may find that the network communication of your app can be split into more individual domains, all representing an individual protocol.

You could also make a single NetworkBehaviour for each individual message (ie each event and each command). They could all be modeled via the RequestResponse behaviour (with an empty response perhaps).

[bnjjj]

Thanks for your answer. So at the end I will have 2 swarm instances right ?

[thomaseizinger]

Thanks for your answer. So at the end I will have 2 swarm instances right ?

Two Swarms are not necessary as there is a custom derive for NetworkBehaviour that allows you to compose multiple Behaviours into a tree structure so you only pass one into the Swarm.

Checkout some of the examples :)

[bnjjj]

I have a related question. I used different topic to send Event or Message and keep the same kind of behavior. But I'm wondering if topics share the same connection ? I mean if I send a lot of events on the topic Event will I have some latencies on the Message topic ?

[thomaseizinger]

With Topic you are saying you are using Gossipsub?

If you don't have/want a mesh network of multiple peers, using Gossipsub seems unnecessary. From what I understand so far, using RequestResponse is probably the best fit.

I don't fully understand the current design you went with so I cannot answer your latency question, do you mind sharing some code?

[bnjjj]

For now I only use the example chat-tokio with floodsub and add handling of topic inside floodsub. Here is an example:

impl NetworkBehaviourEventProcess<FloodsubEvent> for MyBehaviour {
        // Called when `floodsub` produces an event.
        fn inject_event(&mut self, message: FloodsubEvent) {
            let floodsub_topic: floodsub::Topic = floodsub::Topic::new("chat");
            let floodsub_event_topic: floodsub::Topic = floodsub::Topic::new("event");
            if let FloodsubEvent::Message(message) = message {
                if message.topics.contains(&floodsub_topic) {
                    println!(
                        "Message Received: '{:?}' from {:?}",
                        String::from_utf8_lossy(&message.data),
                        message.source
                    );
                }
                if message.topics.contains(&floodsub_event_topic) {
                    println!(
                        "Event Received: '{:?}' from {:?}",
                        String::from_utf8_lossy(&message.data),
                        message.source,
                    );
                }
            }
        }
    }

[thomaseizinger]

Like I said, I don't think Floodsub / Gossipsub is a good fit for your problem. Have you tried using the RequestResponse NetworkBehaviour?