feat(a2a): wire A2A Gateway onto Runtime via TaskStore (issue #5302 Sub-PR D1) - #5313
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…5302 Sub-PR D1) Brings the A2A Gateway back into the Runtime, this time with the unified control-plane stores from apache#5301 Sub-PR A/C as the durable backend instead of the in-memory TaskRegistry that PR apache#5260 introduced. What lands ---------- * A2AGatewayService — task lifecycle controller. Replaces the in-memory TaskRegistry with TaskStore (Sub-PR A/C). A small runtime cache holds the two fields TaskStore does not model: parentTaskId (used to render child-task queries) and taskEpoch (the per-task counter the store requires for stale-write rejection on updateStatus). Both caches are rebuildable from the store on a fresh JVM; the cache keys are taskIds, so the cache size tracks active tasks only. * A2AGatewayHttpHandler — Netty HTTP handler for the REST + SSE API (/a2a/tasks, /a2a/tasks/{id}, /a2a/tasks/{id}/stream, /a2a/health). SSE registers a StatusSubscriber so intermediate PENDING -> RUNNING -> COMPLETED transitions stream to the client. * A2AGatewayServer — Netty HTTP bootstrap. Production wires EventMeshA2ATransport (Runtime-bridged) for the A2AMessageTransport dependency; tests pass an in-process transport. The weather-agent demo from PR apache#5260 is removed — the demo client (A2AGatewayDemo) and the Meta-ized AgentCard registry land in Sub-PR D2. * AgentCardRegistry + InMemoryAgentCardRegistry — minimal discovery surface (isAgentRegistered / registerCard / getCard). A Meta-backed implementation backed by SessionStore (Sub-PR A) lands in D2. Status mapping (PR apache#5260 -> Sub-PR A/C) --------------------------------------- SUBMITTED -> PENDING, WORKING -> RUNNING, CANCELLED -> CANCELED (one L) The legacy wire vocabulary stays available via A2AGatewayService.TaskState and the toLegacyState() helper. JSON response payloads still emit SUBMITTED/WORKING/CANCELLED so existing A2A clients do not break. Documentation ------------- * docs/a2a-protocol/README.md carries an EXPERIMENTAL banner that lists the three pieces still missing for production (TaskExpirer, Meta-ized AgentCard, Testcontainers E2E) — all scheduled for Sub-PR D2. Acceptance against issue apache#5302 ------------------------------ * "A2A transport over the Runtime delivery path" — A2AGatewayService takes an A2AMessageTransport; production wires EventMeshA2ATransport which already bridges A2A onto UniIngressService (issue apache#5301 Sub-PR A's runtime ingress). The parallel InMemoryA2AMessageTransport is no longer required by the gateway path. * "A2A tasks persist through TaskStore and recover across restarts" — createTask / updateStatus / getTask all go through the persistent store. On a fresh JVM, a gateway that had pending tasks sees them with their last persisted status; in-flight work that was awaiting a response will be picked up on the next status callback. Tests (7, all passing) ---------------------- * A2AGatewayServiceTest — 6 tests: create+complete, cancel, cancel-on- unknown, submit-to-unregistered, parent-child index, task-not-found. Uses an in-process TaskStore (mirrors Sub-PR A's test stub) and an in-process A2AMessageTransport that handles A2A's + single-segment wildcards. * A2AGatewaySmokeTest — Netty HTTP /a2a/health loopback check. Not in D1 (Sub-PR D2) --------------------- * TaskExpirer reaper (periodic TaskStore.expireStale sweep). * Meta-backed AgentCardRegistry (SessionStore). * Testcontainers fault-injection E2E.
…5313) A2AGatewayHttpHandler.java: - Remove unused imports (A2AProtocolConstants, A2ATopicFactory, TaskState) - Expand try-catch blocks for limit/offset parsing (EmptyCatchBlock, NeedBraces) - Expand handleList loop control flow (NeedBraces) - Collapse duplicate blank line between package and imports (EmptyLineSeparator) A2AGatewayServiceTest.java: - Expand single-line if-blocks in InProcessTaskStore.listByAgent - Expand if-block in InProcessTransport.matches - Expand if-blocks in tearDown - Move taskId declaration closer to its use (VariableDeclarationUsageDistance) A2AGatewaySmokeTest.java: - Rewrite StubTaskStore / NoopTransport with multi-line method bodies (LeftCurly, RightCurlyAlone, NeedBraces, EmptyLineSeparator) - Add missing static imports (assertEquals, assertNotNull) Build PR apache#5313 fix.
…owup) A2AGatewayServiceTest.java: - Fix ImportOrder: AgentCapabilities before AgentCard (alphabetical) - Fix VariableDeclarationUsageDistance for f: inline taskId into submitTask call so the declaration is closer to first use A2AGatewaySmokeTest.java: - Fix ImportOrder: static Assertions imports before non-static TaskStore import Build PR apache#5313 followup.
…ollowup) The previous fixup broke the test logic by calling TaskResult.getTaskId() which does not exist. Restore the original taskId declaration pattern while keeping the f declaration within 3 lines of its first use: - Declare taskId first - Declare f immediately after - Inline cancelTask result into the assertTrue (no intermediate boolean) - Move f.get() call right after the cancel assertion so f's first use is within 3 lines of its declaration Build PR apache#5313 followup.
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No D1 code changes - all fixes are to satisfy Apache Checkstyle rules for the new files in D1. |
This was referenced Aug 28, 2026
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Brings the A2A Gateway back into the Runtime, this time with the unified control-plane stores from #5301 Sub-PR A/C as the durable backend.
What lands
Status mapping (PR #5260 → Sub-PR A/C)
The legacy wire vocabulary stays available via A2AGatewayService.TaskState and the toLegacyState() helper. JSON response payloads still emit SUBMITTED/WORKING/CANCELLED so existing A2A clients do not break.
Acceptance against issue #5302
Tests (7, all passing locally)
Not in D1 (Sub-PR D2)
Fixes #5302 P1 acceptance criteria (partial: A2A-via-Runtime transport + TaskStore persistence + Experimental banner). Closes #5302 for the parts of the acceptance criteria that this PR delivers; the remaining D2 work will be tracked in a follow-up issue.
Co-authored-by: qqeasonchen qqeasonchen@gmail.com