feat(a2a-nats): add minimal server message_stream handler#357
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Jun 19, 2026
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- Final per-op slice: bootstrap unary reply + JetStream event pump. Cancellation tracking, audit emission, and terminal push-notification dispatch are Bridge-level concerns and land with the Bridge PR.
Bootstrap reply + JetStream event pump complete the unary-style portion of the streaming contract; cancellation tracking, audit emission, and terminal push-notification dispatch are Bridge-level concerns and land with the Bridge PR. Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
PR SummaryMedium Risk Overview On success, the handler replies on NATS with a JSON-RPC bootstrap Errors use the usual JSON-RPC framing (parse/invalid params, handler failures, invalid task id). Requests without a reply subject or id-less notifications are dropped. Cancellation, audit, and terminal push notifications are explicitly deferred to a later Bridge PR. Reviewed by Cursor Bugbot for commit 46c9ce4. Bugbot is set up for automated code reviews on this repo. Configure here. |
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WalkthroughAdds the Changesmessage/stream JSON-RPC handler
Sequence Diagram(s)sequenceDiagram
participant NATS as NATS Subscriber
participant handle as message_stream::handle
participant A2aExecutor
participant NATSReply as NATS Reply Subject
participant JetStream as JetStream task-events
NATS->>handle: payload, reply_subject, prefix
handle->>handle: parse JSON-RPC, extract id, decode SendMessageRequest
handle->>A2aExecutor: message_stream(SendMessageRequest)
A2aExecutor-->>handle: (Task, TaskEventStream)
handle->>handle: derive A2aTaskId from Task
handle->>NATSReply: publish JSON-RPC bootstrap response (Task)
loop TaskEventStream events
handle->>JetStream: publish serialized StreamResponse
end
Note over handle,NATSReply: on any error: publish_bootstrap_error → NATSReply
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Code Coverage SummaryDetailsDiff against mainResults for commit: 46c9ce4 Minimum allowed coverage is ♻️ This comment has been updated with latest results |
…onse Client deserializes the bootstrap as SendMessageResponse (same as message/send), which wraps the task under a task key. Serializing a bare Task fails client-side deserialization and the stream never starts; wrap consistently so the bootstrap shape matches the contract. Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
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The client subscribes with consumer filter
{prefix}.tasks.*.events.{req_id} using its own JSON-RPC string id;
publishing under a server-minted ReqId means every event misses the
filter and the stream never reaches the subscriber. Validate the id is
a string before calling the handler so a non-routable bootstrap fails
fast.
Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
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