FAQ

Do my clients need a broker client library?

No: an HTTP client is enough to publish, curl -N or a browser's EventSource to consume. The events are CloudEvents, so the consumers that do read the broker directly (a Kafka consumer, a JMS application) read the same events.

Is an event delivered exactly once?

No broker behind HTTP can promise that. at-most-once (the default) never delivers an event twice and may lose what a client did not get; at-least-once never loses what was not handed over and may deliver it twice. Give your events stable ids (the CloudEvents id): consumers can drop what they saw. On Artemis, duplicate_detection drops an event published twice.

What happens when a broker goes away?

Its connection becomes unavailable on each node: the routes answer 503 with a Retry-After, the open streams end, an alert is sent once. The client tries again in the background and the connection comes back by itself; the clients coming back resume where they stopped (server-sent events, groups).

Can a caller read any topic?

Not unless the route says so. By default a caller can only shape its own response; the topic is the route's. With allowed_overrides: ["topic"], allowed_topics restricts the topics to glob patterns. The route's own security applies first.

Does it work in a cluster?

Yes: every node has its own clients, and serves the calls that reach it. Webhooks need a Redis the nodes share, to be delivered by one node at a time: see Running in a cluster.

Which Otoroshi version?

Otoroshi 18 and later, on Java 17 and later.

Where are the release notes?

On the releases page. What is planned and done is in the repository's ROADMAP.md.