Struct Gossip 

pub struct Gossip { /* private fields */ }

Gossip protocol to broadcast ephemeral messages to all online nodes interested in the same topic.

Example

// Gossip uses the address book to watch for nodes interested in the same topic.
let gossip = Gossip::builder(address_book, endpoint).spawn().await?;

// Join overlay with given topic.
let handle = gossip.stream([1; 32]).await?;

// Publish a message.
handle.publish(b"Hello, Panda!").await?;

// Subscribe to messages.
let mut rx = handle.subscribe();

tokio::spawn(async move {
    while let Some(Ok(_bytes)) = rx.next().await {
        // ..
    }
});

Ephemeral Messaging

These unreliable “ephemeral” streams are intended to be used for relatively short-lived messages without persistence and catch-up of past state, for example for “Awareness” or “Presence” features. In most cases, messages will only be received if they were published after the subscription was created.

Use LogSync if you wish to receive messages even after being offline for guaranteed eventual consistency.

Self-healing overlay

Gossip-based broadcast overlays rely on membership protocols like HyParView which do not heal from network fragmentation caused, for example, by bootstrap nodes going offline.

p2panda-net uses it’s additional, confidential topic discovery layer in Discovery to automatically heal these partitions. Whenever possible, it allows nodes a higher chance to connect to every participating node, thereby decentralising the entrance points into the network.

Topic Discovery

For gossip to function correctly we need to inform it about discovered nodes who are interested in the same topic. Check out the Discovery module for more information.

Implementations

impl Gossip

pub fn builder(address_book: AddressBook, endpoint: Endpoint) -> Builder

pub async fn stream(&self, topic: TopicId) -> Result<GossipHandle, GossipError>

Join gossip overlay for this topic and return a handle to publish messages to it or receive messages from the network.

pub async fn events(&self) -> Result<Receiver<GossipEvent>, GossipError>

Subscribe to system events.

Trait Implementations

impl Clone for Gossip

fn clone(&self) -> Gossip

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.