A Cloudflare queue reaches exactly one consumer Worker and never the caller
waiting for a reply, so RPC needs a second, addressable path: a Durable
Object the caller holds a WebSocket to while its request is in flight. That
costs a namespace binding and a DO class the application exports, which is
why it is opt-in rather than always on — a project that only publishes and
subscribes should not have to deploy one.
The namespace's class_name must be a Durable Object class the application
exports, delegating to ReplyInboxObjectCore.
The consuming queue must set max_batch_timeout = 0 in wrangler.toml.
The platform default is 5 seconds, which alone exhausts the default reply
budget, so every request() would time out.
Enables brokered request-reply on a
WorkersMessagingArm.A Cloudflare queue reaches exactly one consumer Worker and never the caller waiting for a reply, so RPC needs a second, addressable path: a Durable Object the caller holds a WebSocket to while its request is in flight. That costs a namespace binding and a DO class the application exports, which is why it is opt-in rather than always on — a project that only publishes and subscribes should not have to deploy one.
The namespace's
class_namemust be a Durable Object class the application exports, delegating toReplyInboxObjectCore.The consuming queue must set
max_batch_timeout = 0inwrangler.toml. The platform default is 5 seconds, which alone exhausts the default reply budget, so everyrequest()would time out.Since
0.2.0