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3 unstable releases
0.29.0 | Mar 12, 2021 |
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0.27.1 | Apr 3, 2021 |
0.27.0 | Apr 2, 2021 |
0.0.0 |
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#2 in #tetsy-libp2p
49 downloads per month
Used in tetsy-libp2p
1MB
22K
SLoC
tetsy-libp2p-gossipsub
Gossipsub is a P2P pubsub (publish/subscription) routing layer designed to extend upon floodsub and meshsub routing protocols.
Overview
Note: The gossipsub protocol specifications (https://github.com/libp2p/specs/tree/master/pubsub/gossipsub) provide an outline for the routing protocol. They should be consulted for further detail.
Gossipsub is a blend of meshsub for data and randomsub for mesh metadata. It provides bounded degree and amplification factor with the meshsub construction and augments it using gossip propagation of metadata with the randomsub technique.
The router maintains an overlay mesh network of peers on which to efficiently send messages and metadata. Peers use control messages to broadcast and request known messages and subscribe/unsubscribe from topics in the mesh network.
Important Discrepancies
This section outlines the current implementation's potential discrepancies from that of other implementations, due to undefined elements in the current specification.
-
Topics - In gossipsub, topics configurable by the
hash_topics
configuration parameter. Topics are of typeTopicHash
. The current go implementation uses raw utf-8 strings, and this is default configuration in tetsy-libp2p. Topics can be hashed (SHA256 hashed then base64 encoded) by setting thehash_topics
configuration parameter to true. -
Sequence Numbers - A message on the gossipsub network is identified by the source
tetsy_libp2p_core::PeerId
and a nonce (sequence number) of the message. The sequence numbers in this implementation are sent as raw bytes across the wire. They are 64-bit big-endian unsigned integers. They are chosen at random in this implementation of gossipsub, but are sequential in the current go implementation.
Using Gossipsub
GossipsubConfig
The GossipsubConfig
struct specifies various network performance/tuning configuration
parameters. Specifically it specifies:
This struct implements the Default
trait and can be initialised via
[GossipsubConfig::default()
].
Gossipsub
The Gossipsub
struct implements the tetsy_libp2p_swarm::NetworkBehaviour
trait allowing it to
act as the routing behaviour in a tetsy_libp2p_swarm::Swarm
. This struct requires an instance of
tetsy_libp2p_core::PeerId
and GossipsubConfig
.
Example
An example of initialising a gossipsub compatible swarm:
use tetsy_libp2p_gossipsub::GossipsubEvent;
use tetsy_libp2p_core::{identity::Keypair,transport::{Transport, MemoryTransport}, Multiaddr};
use tetsy_libp2p_gossipsub::MessageAuthenticity;
let local_key = Keypair::generate_ed25519();
let local_peer_id = tetsy_libp2p_core::PeerId::from(local_key.public());
// Set up an encrypted TCP Transport over the Mplex
// This is test transport (memory).
let noise_keys = tetsy_libp2p_noise::Keypair::<tetsy_libp2p_noise::X25519Spec>::new().into_authentic(&local_key).unwrap();
let transport = MemoryTransport::default()
.upgrade(tetsy_libp2p_core::upgrade::Version::V1)
.authenticate(tetsy_libp2p_noise::NoiseConfig::xx(noise_keys).into_authenticated())
.multiplex(tetsy_libp2p_mplex::MplexConfig::new())
.boxed();
// Create a Gossipsub topic
let topic = tetsy_libp2p_gossipsub::IdentTopic::new("example");
// Set the message authenticity - How we expect to publish messages
// Here we expect the publisher to sign the message with their key.
let message_authenticity = MessageAuthenticity::Signed(local_key);
// Create a Swarm to manage peers and events
let mut swarm = {
// set default parameters for gossipsub
let gossipsub_config = tetsy_libp2p_gossipsub::GossipsubConfig::default();
// build a gossipsub network behaviour
let mut gossipsub: tetsy_libp2p_gossipsub::Gossipsub =
tetsy_libp2p_gossipsub::Gossipsub::new(message_authenticity, gossipsub_config).unwrap();
// subscribe to the topic
gossipsub.subscribe(&topic);
// create the swarm
tetsy_libp2p_swarm::Swarm::new(
transport,
gossipsub,
local_peer_id,
)
};
// Listen on a memory transport.
let memory: Multiaddr = tetsy_libp2p_core::multiaddr::Protocol::Memory(10).into();
let addr = tetsy_libp2p_swarm::Swarm::listen_on(&mut swarm, memory).unwrap();
println!("Listening on {:?}", addr);
Dependencies
~12–19MB
~375K SLoC