Advanced Configuration

Generating Config Files

ros-z can generate JSON5 config files matching rmw_zenoh_cpp defaults. This is opt-in via the generate-configs feature flag.

cargo build --features generate-configs

Output location:

target/debug/build/ros-z-*/out/ros_z_config/
  ├── DEFAULT_ROSZ_ROUTER_CONFIG.json5
  └── DEFAULT_ROSZ_SESSION_CONFIG.json5

Specify a custom directory using the ROS_Z_CONFIG_OUTPUT_DIR environment variable:

Absolute path:

ROS_Z_CONFIG_OUTPUT_DIR=/etc/zenoh cargo build --features generate-configs

Relative path (from package root):

ROS_Z_CONFIG_OUTPUT_DIR=./config cargo build --features generate-configs

From workspace root:

ROS_Z_CONFIG_OUTPUT_DIR=$PWD/config cargo build -p ros-z --features generate-configs

Tip

Generated files include inline comments explaining each setting, making them perfect documentation references.

let ctx = ZContextBuilder::default()
    .with_config_file("./config/DEFAULT_ROSZ_SESSION_CONFIG.json5")
    .build()?;

Setting	Router	Session	Purpose
Mode	`router`	`peer`	Router relays messages, peers connect directly
Listen Endpoint	`tcp/[::]:7447`	-	Router accepts connections
Connect Endpoint	-	`tcp/localhost:7447`	Session connects to router
Multicast	Disabled	Disabled	Uses TCP gossip for discovery
Unicast Timeout	60s	60s	Handles slow networks/large deployments
Query Timeout	10min	10min	Long-running service calls
Max Sessions	10,000	-	Supports concurrent node startup
Keep-Alive	2s	2s	Optimized for loopback

Note

These defaults are tuned for ROS 2 deployments and match rmw_zenoh_cpp exactly. Only modify them if you have specific performance requirements.