nats

NATS Capability Provider

This capability provider is an implementation of the wasmcloud:messaging contract. It exposes publish, request, and subscribe functionality to actors.

Link Definition Configuration Settings

To configure this provider, use the following link settings in link definitions:

Property	Description
SUBSCRIPTION	A comma-separated list of subscription topics. If a subscription is a queue subscription, follow the subscription with "|" and the queue group name. For example, the setting SUBSCRIPTION=example.actor,example.task|work_queue subscribes to the topic example.actor and the topic example.task in the queue group work_queue.
URI	NATS connection uri. If not specified, the default is 0.0.0.0:4222
CLIENT_JWT	Optional JWT auth token. For JWT authentication, both CLIENT_JWT and CLIENT_SEED must be provided.
CLIENT_SEED	Private seed for JWT authentication.

⚠️ A word of caution, setting the subscription link definition value to wasmbus.evt.* or wasmbus.evt.<your_lattice_prefix> will cause that actor to infinite loop when handling a message. We publish events for when actor invocations succeed or fail on the wasmbus.evt.<prefix> topic, and the act of handling that message results in another invocation event.