Infrastructure Services (Relay + Rendezvous)

Soma uses two lightweight libp2p infrastructure services to improve discovery and connectivity.

Relay (soma-relayd)

The relay service runs the libp2p Circuit Relay v2 server behaviour. Peers that cannot establish direct connections can reserve slots on the relay and route encrypted libp2p traffic through it.

Rendezvous (soma-rendezvousd)

The rendezvous service runs the libp2p Rendezvous server behaviour. Peers register under namespaces and query for other registered peers to bootstrap connectivity.

For how peers consume relay/rendezvous (and the relevant CLI flags), see docs/src/architecture/peer-connectivity.md.

Identity Persistence

Both services persist a libp2p keypair so their Peer ID remains stable across restarts.

• Env var: SOMA_DATA_DIR
• Defaults:
  • Relay: ./data/relay/identity.key
  • Rendezvous: ./data/rendezvous/identity.key

Transports

The services listen on multiple transports simultaneously:

• TCP: baseline compatibility
• QUIC (UDP): performance and often better NAT behavior (but UDP may be blocked)
• WebSocket (WS): helpful for restrictive networks and web-like environments

The exact listen addrs are currently configured in the crate defaults.

soma-net Swarm Builder

Soma centralizes libp2p transport wiring in soma-net. libp2p’s SwarmBuilder uses a typestate API; to compose multiple transports, the call order matters:

TCP -> QUIC -> DNS -> WebSocket -> Behaviour

If the swarm is built without QUIC support, attempting to listen_on("/udp/.../quic-v1") will fail with MultiaddrNotSupported.

Health + Metrics

Both services expose an HTTP server (Axum) strictly for:

• GET /healthz
• GET /metrics (Prometheus text)

Service-specific counters track relay reservations/circuits and rendezvous registrations/discovers.