What is gossipsub's equivalent of add_now_to_partial_view()?

[laptou]

I'm trying to adapt the chat example here (the one that uses Floodsub with mDNS) to use Gossipsub instead, but I can't figure it out. Here's what I tried:

#[derive(NetworkBehaviour)]
#[behaviour(out_event = "CombinedNetworkBehaviourEvent")]

struct CombinedNetworkBehaviour {
    mdns: Mdns,
    gossipsub: Gossipsub,
}

impl NetworkBehaviourEventProcess<GossipsubEvent> for CombinedNetworkBehaviour {
    fn inject_event(&mut self, event: GossipsubEvent) {
        debug!("received gossipsub event: {:?}", event);
    }
}

impl NetworkBehaviourEventProcess<MdnsEvent> for CombinedNetworkBehaviour {
    fn inject_event(&mut self, event: MdnsEvent) {
        debug!("received mdns event: {:?}", event);

        match event {
            MdnsEvent::Discovered(list) => {
                for (peer, addr) in list {
                    debug!("mdns: discovered peer {:?} at {:?}", peer, addr);
                    self.gossipsub.inject_connected(&peer)
                }
            }
            MdnsEvent::Expired(list) => {
                for (peer, addr) in list {
                    debug!("mdns: expired peer {:?} at {:?}", peer, addr);
                    self.gossipsub.inject_disconnected(&peer)
                }
            }
        }
    }
}

impl CombinedNetworkBehaviour {
    pub fn publish<H: libp2p::gossipsub::Hasher>(
        &mut self,
        topic: Topic<H>,
        data: impl Into<Vec<u8>>,
    ) -> Result<MessageId, libp2p::gossipsub::error::PublishError> {
        self.gossipsub.publish(topic, data)
    }
}

enum CombinedNetworkBehaviourEvent {
    Mdns(MdnsEvent),
    Gossip(GossipsubEvent),
}

impl From<MdnsEvent> for CombinedNetworkBehaviourEvent {
    fn from(e: MdnsEvent) -> Self {
        CombinedNetworkBehaviourEvent::Mdns(e)
    }
}

impl From<GossipsubEvent> for CombinedNetworkBehaviourEvent {
    fn from(e: GossipsubEvent) -> Self {
        CombinedNetworkBehaviourEvent::Gossip(e)
    }
}

But this doesn't work when I try to publish a message: I get the error that there are insufficient peers.
I also tried using add_explicit_peer(), and it did work, but I'm not sure if it's actually doing what I want it to do.

[mxinden]

👋 Hi @laptou,

impl NetworkBehaviourEventProcess<MdnsEvent> for CombinedNetworkBehaviour {
    fn inject_event(&mut self, event: MdnsEvent) {
        debug!("received mdns event: {:?}", event);

        match event {
            MdnsEvent::Discovered(list) => {
                for (peer, addr) in list {
                    debug!("mdns: discovered peer {:?} at {:?}", peer, addr);
                    self.gossipsub.inject_connected(&peer)

inject_connected is a method on the NetworkBehaviour trait. As a rule of thumb, you will likely never need to call a method on the NetworkBehaviour trait as a user of rust-libp2p.

Instead, as you suggested add_explicit_peer could be an option, though that has additional implications, like staying connected to that peer at all times.

What I would do when building a basic example is connect to nodes discovered through mdns. The gossipsub subsystem will be notified of the new connection and then keep track of the peer. Something along the lines of self.dial_addr(addr).

            MdnsEvent::Expired(list) => {
                for (peer, addr) in list {
                    debug!("mdns: expired peer {:?} at {:?}", peer, addr);
                    self.gossipsub.inject_disconnected(&peer)

Same here, calling the internal inject_disconnected method is not the way to go. If I understand your goal correctly, ignoring the address expiration can be ignored.

impl CombinedNetworkBehaviour {
    pub fn publish<H: libp2p::gossipsub::Hasher>(
        &mut self,
        topic: Topic<H>,
        data: impl Into<Vec<u8>>,
    ) -> Result<MessageId, libp2p::gossipsub::error::PublishError> {
        self.gossipsub.publish(topic, data)

Note: You could as well just call swarm.behaviour_mut().gossip.publish(...).

---

Let us know if the above is of any help. Curious what you end up building.