Sessions

A Session is your application's connection to the Zenoh network. All Zenoh operations — publishing, subscribing, querying — go through a session.

Opening a Session

use zenoh::prelude::*;
 
// Default configuration (peer mode, multicast scouting)
let session = zenoh::open(zenoh::config::default()).await.unwrap();
 
// Custom configuration from file
let config = zenoh::config::from_file("zenoh.json5").unwrap();
let session = zenoh::open(config).await.unwrap();

Session Modes

Mode	Description
`peer`	Direct peer-to-peer communication; suitable for LAN deployments
`client`	Connects to a router; suitable for constrained devices or WAN
`router`	Acts as a routing node; combines `peer` with routing capabilities

// zenoh.json5
{
  mode: "client",
  connect: {
    endpoints: ["tcp/router.example.com:7447"],
  },
}

Session Lifecycle

A session holds open connections and subscriptions for its entire lifetime. Close it explicitly when done to release resources:

session.close().await.unwrap();

Or let it drop — Zenoh will clean up gracefully.

Multiple Sessions

An application can open multiple sessions simultaneously (e.g., to connect to two separate Zenoh networks or to use different configurations).