ipfs_kad_example/
main.rs

1// Copyright 2018 Parity Technologies (UK) Ltd.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a
4// copy of this software and associated documentation files (the "Software"),
5// to deal in the Software without restriction, including without limitation
6// the rights to use, copy, modify, merge, publish, distribute, sublicense,
7// and/or sell copies of the Software, and to permit persons to whom the
8// Software is furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
14// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
19// DEALINGS IN THE SOFTWARE.
20
21#![doc = include_str!("../README.md")]
22
23use std::{
24    num::NonZeroUsize,
25    ops::Add,
26    time::{Duration, Instant},
27};
28
29use anyhow::{bail, Result};
30use clap::Parser;
31use futures::StreamExt;
32use libp2p::{
33    bytes::BufMut,
34    identity, kad, noise,
35    swarm::{StreamProtocol, SwarmEvent},
36    tcp, yamux, PeerId,
37};
38use tracing_subscriber::EnvFilter;
39
40const BOOTNODES: [&str; 4] = [
41    "QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN",
42    "QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa",
43    "QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb",
44    "QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt",
45];
46
47const IPFS_PROTO_NAME: StreamProtocol = StreamProtocol::new("/ipfs/kad/1.0.0");
48
49#[tokio::main]
50async fn main() -> Result<()> {
51    let _ = tracing_subscriber::fmt()
52        .with_env_filter(EnvFilter::from_default_env())
53        .try_init();
54
55    // Create a random key for ourselves.
56    let local_key = identity::Keypair::generate_ed25519();
57
58    let mut swarm = libp2p::SwarmBuilder::with_existing_identity(local_key.clone())
59        .with_tokio()
60        .with_tcp(
61            tcp::Config::default(),
62            noise::Config::new,
63            yamux::Config::default,
64        )?
65        .with_dns()?
66        .with_behaviour(|key| {
67            // Create a Kademlia behaviour.
68            let mut cfg = kad::Config::new(IPFS_PROTO_NAME);
69            cfg.set_query_timeout(Duration::from_secs(5 * 60));
70            let store = kad::store::MemoryStore::new(key.public().to_peer_id());
71            kad::Behaviour::with_config(key.public().to_peer_id(), store, cfg)
72        })?
73        .build();
74
75    // Add the bootnodes to the local routing table. `libp2p-dns` built
76    // into the `transport` resolves the `dnsaddr` when Kademlia tries
77    // to dial these nodes.
78    for peer in &BOOTNODES {
79        swarm
80            .behaviour_mut()
81            .add_address(&peer.parse()?, "/dnsaddr/bootstrap.libp2p.io".parse()?);
82    }
83
84    let cli_opt = Opt::parse();
85
86    match cli_opt.argument {
87        CliArgument::GetPeers { peer_id } => {
88            let peer_id = peer_id.unwrap_or(PeerId::random());
89            println!("Searching for the closest peers to {peer_id}");
90            swarm.behaviour_mut().get_closest_peers(peer_id);
91        }
92        CliArgument::PutPkRecord {} => {
93            println!("Putting PK record into the DHT");
94
95            let mut pk_record_key = vec![];
96            pk_record_key.put_slice("/pk/".as_bytes());
97            pk_record_key.put_slice(swarm.local_peer_id().to_bytes().as_slice());
98
99            let mut pk_record =
100                kad::Record::new(pk_record_key, local_key.public().encode_protobuf());
101            pk_record.publisher = Some(*swarm.local_peer_id());
102            pk_record.expires = Some(Instant::now().add(Duration::from_secs(60)));
103
104            swarm
105                .behaviour_mut()
106                .put_record(pk_record, kad::Quorum::N(NonZeroUsize::new(3).unwrap()))?;
107        }
108    }
109
110    loop {
111        let event = swarm.select_next_some().await;
112
113        match event {
114            SwarmEvent::Behaviour(kad::Event::OutboundQueryProgressed {
115                result: kad::QueryResult::GetClosestPeers(Ok(ok)),
116                ..
117            }) => {
118                // The example is considered failed as there
119                // should always be at least 1 reachable peer.
120                if ok.peers.is_empty() {
121                    bail!("Query finished with no closest peers.")
122                }
123
124                println!("Query finished with closest peers: {:#?}", ok.peers);
125
126                return Ok(());
127            }
128            SwarmEvent::Behaviour(kad::Event::OutboundQueryProgressed {
129                result:
130                    kad::QueryResult::GetClosestPeers(Err(kad::GetClosestPeersError::Timeout {
131                        ..
132                    })),
133                ..
134            }) => {
135                bail!("Query for closest peers timed out")
136            }
137            SwarmEvent::Behaviour(kad::Event::OutboundQueryProgressed {
138                result: kad::QueryResult::PutRecord(Ok(_)),
139                ..
140            }) => {
141                println!("Successfully inserted the PK record");
142
143                return Ok(());
144            }
145            SwarmEvent::Behaviour(kad::Event::OutboundQueryProgressed {
146                result: kad::QueryResult::PutRecord(Err(err)),
147                ..
148            }) => {
149                bail!(anyhow::Error::new(err).context("Failed to insert the PK record"));
150            }
151            _ => {}
152        }
153    }
154}
155
156#[derive(Parser, Debug)]
157#[command(name = "libp2p Kademlia DHT example")]
158struct Opt {
159    #[command(subcommand)]
160    argument: CliArgument,
161}
162
163#[derive(Debug, Parser)]
164enum CliArgument {
165    GetPeers {
166        #[arg(long)]
167        peer_id: Option<PeerId>,
168    },
169    PutPkRecord {},
170}
ipfs_kad_example/main.rs

ipfs_kad_example/
main.rs
