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RPC for external read + write

Why you need it​

External callers need to read durable state, mutate it, and optionally move the Flow — atomically from the caller’s point of view.

Code examples​

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@rpc
def nudge(self, context, message: str) -> RPCResult:
    status.set(context, "nudged")
    unblock.publish(context, message)
    return RPCResult(output="ok")

Declare @rpc / RPC methods on the Flow; invoke via client InvokeRPC.

How Dex implements it​

The server routes InvokeRPC to the Worker, applies Attribute locks if requested, and commits Attribute/channel side effects with the RPC result.

Traditional workarounds​

Without Dex: separate read APIs, write APIs, and “signal” endpoints with careful locking — often inconsistent under concurrency.