feat(swarm): set default for idle-connection-timeout to 10s (#4967)

## Description

With the move to a global idle-connection-timeout, connections are being
closed much more aggressively. This causes problems in situations where,
e.g. an application wants to use a connection shortly after an event has
been emitted from the `Swarm`. With a default of 0 seconds, such a
connection is instantly considered idle and therefore closed, despite
the application wanting to use it again just moments later. Whilst it is
possible to structure application code to mitigate this, it is
unnecessarily complicated.

Additionally, connections being closed instantly if not in use is a
foot-gun for newcomers to the library.

From a technical point-of-view, instantly closing idle connections is
nice. In reality, it is an impractical default. Hence, we change this
default to 10s.

10 seconds is considered to be an acceptable default as it strikes a
balance between allowing some pause between network activity, yet frees
up resources that are (supposedly) no longer needed.

Resolves: #4912.

examples/autonat/src/bin/autonat_client.rs

@@ -62,7 +62,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
             yamux::Config::default,
         )?
         .with_behaviour(|key| Behaviour::new(key.public()))?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
         .build();
 
     swarm.listen_on(

examples/autonat/src/bin/autonat_server.rs

@@ -20,7 +20,7 @@
 
 #![doc = include_str!("../../README.md")]
 
-use std::{error::Error, net::Ipv4Addr, time::Duration};
+use std::{error::Error, net::Ipv4Addr};
 
 use clap::Parser;
 use futures::StreamExt;
@@ -56,7 +56,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
             yamux::Config::default,
         )?
         .with_behaviour(|key| Behaviour::new(key.public()))?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
         .build();
 
     swarm.listen_on(

examples/browser-webrtc/src/main.rs

@@ -1,9 +1,6 @@
 #![allow(non_upper_case_globals)]
 
-use std::{
-    net::{Ipv4Addr, SocketAddr},
-    time::Duration,
-};
+use std::net::{Ipv4Addr, SocketAddr};
 
 use anyhow::Result;
 use axum::{
@@ -41,11 +38,6 @@ async fn main() -> anyhow::Result<()> {
             .map(|(peer_id, conn), _| (peer_id, StreamMuxerBox::new(conn))))
         })?
         .with_behaviour(|_| ping::Behaviour::default())?
-        .with_swarm_config(|cfg| {
-            cfg.with_idle_connection_timeout(
-                Duration::from_secs(u64::MAX), // Allows us to observe the pings.
-            )
-        })
         .build();
 
     let address_webrtc = Multiaddr::from(Ipv4Addr::UNSPECIFIED)

examples/chat/src/main.rs

@@ -84,7 +84,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
                 mdns::tokio::Behaviour::new(mdns::Config::default(), key.public().to_peer_id())?;
             Ok(MyBehaviour { gossipsub, mdns })
         })?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
         .build();
 
     // Create a Gossipsub topic

examples/dcutr/src/main.rs

@@ -20,7 +20,7 @@
 
 #![doc = include_str!("../README.md")]
 
-use std::{error::Error, str::FromStr, time::Duration};
+use std::{error::Error, str::FromStr};
 
 use clap::Parser;
 use futures::{executor::block_on, future::FutureExt, stream::StreamExt};
@@ -105,7 +105,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
                 )),
                 dcutr: dcutr::Behaviour::new(keypair.public().to_peer_id()),
             })?
-            .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
             .build();
 
     swarm

examples/distributed-key-value-store/src/main.rs

@@ -20,7 +20,7 @@
 
 #![doc = include_str!("../README.md")]
 
-use std::{error::Error, time::Duration};
+use std::error::Error;
 
 use futures::stream::StreamExt;
 use libp2p::{
@@ -68,7 +68,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
                 )?,
             })
         })?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
         .build();
 
     swarm.behaviour_mut().kademlia.set_mode(Some(Mode::Server));

examples/identify/src/main.rs

@@ -20,7 +20,7 @@
 
 #![doc = include_str!("../README.md")]
 
-use std::{error::Error, time::Duration};
+use std::error::Error;
 
 use futures::StreamExt;
 use libp2p::{core::multiaddr::Multiaddr, identify, noise, swarm::SwarmEvent, tcp, yamux};
@@ -45,7 +45,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
                 key.public(),
             ))
         })?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
         .build();
 
     // Tell the swarm to listen on all interfaces and a random, OS-assigned

examples/ipfs-kad/src/main.rs

@@ -70,7 +70,6 @@ async fn main() -> Result<()> {
             let store = kad::store::MemoryStore::new(key.public().to_peer_id());
             kad::Behaviour::with_config(key.public().to_peer_id(), store, cfg)
         })?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
         .build();
 
     // Add the bootnodes to the local routing table. `libp2p-dns` built

examples/ipfs-private/src/main.rs

@@ -20,7 +20,7 @@
 
 #![doc = include_str!("../README.md")]
 
-use std::{env, error::Error, fs, path::Path, str::FromStr, time::Duration};
+use std::{env, error::Error, fs, path::Path, str::FromStr};
 
 use either::Either;
 use futures::prelude::*;
@@ -152,7 +152,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
                 ping: ping::Behaviour::new(ping::Config::new()),
             })
         })?
-        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
         .build();
 
     println!("Subscribing to {gossipsub_topic:?}");

examples/metrics/src/main.rs

@@ -20,7 +20,7 @@
 
 #![doc = include_str!("../README.md")]
 
-use std::{error::Error, time::Duration};
+use std::error::Error;
 
 use futures::StreamExt;
 use libp2p::{
@@ -54,7 +54,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
         )?
         .with_bandwidth_metrics(&mut metric_registry)
         .with_behaviour(|key| Behaviour::new(key.public()))?
-        .with_swarm_config(|cfg| cfg.with_idle_connection_timeout(Duration::from_secs(u64::MAX)))
         .build();
 
     swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?)?;

examples/rendezvous/src/bin/rzv-discover.rs

@@ -53,7 +53,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
             rendezvous: rendezvous::client::Behaviour::new(key.clone()),
             ping: ping::Behaviour::new(ping::Config::new().with_interval(Duration::from_secs(1))),
         })?
-        .with_swarm_config(|cfg| cfg.with_idle_connection_timeout(Duration::from_secs(5)))
         .build();
 
     swarm.dial(rendezvous_point_address.clone()).unwrap();

examples/rendezvous/src/bin/rzv-identify.rs

@@ -56,7 +56,6 @@ async fn main() {
             ping: ping::Behaviour::new(ping::Config::new().with_interval(Duration::from_secs(1))),
         })
         .unwrap()
-        .with_swarm_config(|cfg| cfg.with_idle_connection_timeout(Duration::from_secs(5)))
         .build();
 
     let _ = swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse().unwrap());

examples/rendezvous/src/bin/rzv-register.rs

@@ -52,7 +52,6 @@ async fn main() {
             ping: ping::Behaviour::new(ping::Config::new().with_interval(Duration::from_secs(1))),
         })
         .unwrap()
-        .with_swarm_config(|cfg| cfg.with_idle_connection_timeout(Duration::from_secs(5)))
         .build();
 
     // In production the external address should be the publicly facing IP address of the rendezvous

examples/rendezvous/src/main.rs

@@ -55,7 +55,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
             rendezvous: rendezvous::server::Behaviour::new(rendezvous::server::Config::default()),
             ping: ping::Behaviour::new(ping::Config::new().with_interval(Duration::from_secs(1))),
         })?
-        .with_swarm_config(|cfg| cfg.with_idle_connection_timeout(Duration::from_secs(5)))
         .build();
 
     let _ = swarm.listen_on("/ip4/0.0.0.0/tcp/62649".parse().unwrap());

interop-tests/src/arch.rs

@@ -49,7 +49,6 @@ pub(crate) mod native {
                     .with_tokio()
                     .with_quic()
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/udp/0/quic-v1"),
             ),
@@ -62,7 +61,6 @@ pub(crate) mod native {
                         mplex::MplexConfig::default,
                     )?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0"),
             ),
@@ -75,7 +73,6 @@ pub(crate) mod native {
                         yamux::Config::default,
                     )?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0"),
             ),
@@ -88,7 +85,6 @@ pub(crate) mod native {
                         mplex::MplexConfig::default,
                     )?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0"),
             ),
@@ -101,7 +97,6 @@ pub(crate) mod native {
                         yamux::Config::default,
                     )?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0"),
             ),
@@ -111,7 +106,6 @@ pub(crate) mod native {
                     .with_websocket(tls::Config::new, mplex::MplexConfig::default)
                     .await?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0/ws"),
             ),
@@ -121,7 +115,6 @@ pub(crate) mod native {
                     .with_websocket(tls::Config::new, yamux::Config::default)
                     .await?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0/ws"),
             ),
@@ -131,7 +124,6 @@ pub(crate) mod native {
                     .with_websocket(noise::Config::new, mplex::MplexConfig::default)
                     .await?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0/ws"),
             ),
@@ -141,7 +133,6 @@ pub(crate) mod native {
                     .with_websocket(noise::Config::new, yamux::Config::default)
                     .await?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/tcp/0/ws"),
             ),
@@ -155,7 +146,6 @@ pub(crate) mod native {
                         ))
                     })?
                     .with_behaviour(behaviour_constructor)?
-                    .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(5)))
                     .build(),
                 format!("/ip4/{ip}/udp/0/webrtc-direct"),
             ),

libp2p/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 - Deprecate `void` crate.
   See [PR 5676](https://github.com/libp2p/rust-libp2p/pull/5676).
+- Update default for idle-connection-timeout to 10s.
+  See [PR 4967](https://github.com/libp2p/rust-libp2p/pull/4967).
 
 - Expose swarm builder phase errors.
   See [PR 5726](https://github.com/libp2p/rust-libp2p/pull/5726).

libp2p/Cargo.toml

@@ -142,7 +142,6 @@ clap = { version = "4.1.6", features = ["derive"] }
 tokio = { workspace = true, features = [ "io-util", "io-std", "macros", "rt", "rt-multi-thread"] }
 
 libp2p-mplex = { workspace = true }
-libp2p-noise = { workspace = true }
 libp2p-tcp = { workspace = true, features = ["tokio"] }
 tracing-subscriber = { workspace = true, features = ["env-filter"] }
 

libp2p/src/tutorials/ping.rs

@@ -232,9 +232,6 @@
 //!             yamux::Config::default,
 //!         )?
 //!         .with_behaviour(|_| ping::Behaviour::default())?
-//!         .with_swarm_config(|cfg| {
-//!             cfg.with_idle_connection_timeout(Duration::from_secs(u64::MAX))
-//!         })
 //!         .build();
 //!
 //!     Ok(())
@@ -287,9 +284,6 @@
 //!             yamux::Config::default,
 //!         )?
 //!         .with_behaviour(|_| ping::Behaviour::default())?
-//!         .with_swarm_config(|cfg| {
-//!             cfg.with_idle_connection_timeout(Duration::from_secs(u64::MAX))
-//!         })
 //!         .build();
 //!
 //!     // Tell the swarm to listen on all interfaces and a random, OS-assigned
@@ -335,9 +329,6 @@
 //!             yamux::Config::default,
 //!         )?
 //!         .with_behaviour(|_| ping::Behaviour::default())?
-//!         .with_swarm_config(|cfg| {
-//!             cfg.with_idle_connection_timeout(Duration::from_secs(u64::MAX))
-//!         })
 //!         .build();
 //!
 //!     // Tell the swarm to listen on all interfaces and a random, OS-assigned

protocols/kad/src/behaviour/test.rs

@@ -64,8 +64,7 @@ fn build_node_with_config(cfg: Config) -> (Multiaddr, TestSwarm) {
         transport,
         behaviour,
         local_id,
-        swarm::Config::with_async_std_executor()
-            .with_idle_connection_timeout(Duration::from_secs(5)),
+        swarm::Config::with_async_std_executor(),
     );
 
     let address: Multiaddr = Protocol::Memory(random::<u64>()).into();

protocols/relay/tests/lib.rs

@@ -416,10 +416,7 @@ fn reuse_connection() {
         .with(Protocol::P2p(relay_peer_id))
         .with(Protocol::P2pCircuit);
 
-    // To reuse the connection, we need to ensure it is not shut down due to being idle.
-    let mut client = build_client_with_config(
-        Config::with_async_std_executor().with_idle_connection_timeout(Duration::from_secs(1)),
-    );
+    let mut client = build_client();
     let client_peer_id = *client.local_peer_id();
 
     client.dial(relay_addr).unwrap();

swarm-test/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 - Add `tokio` runtime support and make `tokio` and `async-std` runtimes optional behind features.
   See [PR 5551].
+  - Update default for idle-connection-timeout to 10s on `SwarmExt::new_ephemeral` methods.
+  See [PR 4967](https://github.com/libp2p/rust-libp2p/pull/4967).
 
 [PR 5551]: https://github.com/libp2p/rust-libp2p/pull/5551
 

swarm-test/src/lib.rs

@@ -246,13 +246,7 @@ where
             transport,
             behaviour_fn(identity),
             peer_id,
-            libp2p_swarm::Config::with_async_std_executor()
-                // Some tests need
-                // connections to be kept
-                // alive beyond what the
-                // individual behaviour
-                // configures.,
-                .with_idle_connection_timeout(Duration::from_secs(5)),
+            libp2p_swarm::Config::with_async_std_executor(),
         )
     }
 
@@ -279,12 +273,7 @@ where
             transport,
             behaviour_fn(identity),
             peer_id,
-            libp2p_swarm::Config::with_tokio_executor()
-                .with_idle_connection_timeout(Duration::from_secs(5)), /* Some tests need
-                                                                        * connections to be kept
-                                                                        * alive beyond what the
-                                                                        * individual behaviour
-                                                                        * configures., */
+            libp2p_swarm::Config::with_tokio_executor(),
         )
     }
 

swarm/CHANGELOG.md

@@ -5,10 +5,13 @@
 
 - Deprecate `void` crate.
   See [PR 5676](https://github.com/libp2p/rust-libp2p/pull/5676).
-  
+
 - Fix `cargo clippy` warnings in `rustc 1.84.0-beta.1`.
   See [PR 5700](https://github.com/libp2p/rust-libp2p/pull/5700).
 
+- Update default for idle-connection-timeout to 10s.
+  See [PR 4967](https://github.com/libp2p/rust-libp2p/pull/4967).
+
 ## 0.45.1
 
 - Update `libp2p-swarm-derive` to version `0.35.0`, see [PR 5545]

swarm/src/connection/pool.rs

@@ -989,7 +989,7 @@ impl PoolConfig {
             task_command_buffer_size: 32,
             per_connection_event_buffer_size: 7,
             dial_concurrency_factor: NonZeroU8::new(8).expect("8 > 0"),
-            idle_connection_timeout: Duration::ZERO,
+            idle_connection_timeout: Duration::from_secs(10),
             substream_upgrade_protocol_override: None,
             max_negotiating_inbound_streams: 128,
         }