feat: add GetTaskQueueUserData RPC to admin service

[veeral-patel]

What changed?

This PR adds a new GetTaskQueueUserData RPC to the admin service.

Given a namespace, task queue name, task queue type, and optional partition ID (default is 0, which is root), it returns the user data currently loaded by that partition.

This PR wraps the existing GetTaskQueueUserData RPC in Matching Service. We will also create a tdbg command which calls this Admin Service RPC, in a separate PR.

Why?

Each task queue family has associated metadata, stored in TaskQueueUserData. Metadata related to worker versioning, queue rate limiting, fairness are all stored in TaskQueueUserData.

TaskQueueUserData is replicated from the root partition to all other partitions.

However, there is no admin-accessible way to read the user data loaded by a specific partition or compare versions across partitions to diagnose replication lag.

Files changed

File	Change
proto/internal/.../adminservice/v1/request_response.proto	Added GetTaskQueueUserDataRequest and GetTaskQueueUserDataResponse messages
proto/internal/.../adminservice/v1/service.proto	Added GetTaskQueueUserData RPC to AdminService
service/frontend/admin_handler.go	Implemented AdminHandler.GetTaskQueueUserData: validates request, resolves namespace → ID, builds partition RPC name via tqid, calls matching service, returns per-type entry + version
service/frontend/admin_handler_test.go	Added unit tests

How did you test it?

• built
• run locally and tested manually
• added new unit test(s)
• added new integration test(s) - not applicable, not touching persistence layer
• added new functional test(s)

Unit tests

100% unit test coverage

Test case	Input	Expected
Nil request	request == nil	errRequestNotSet
Empty namespace	namespace == ""	errNamespaceNotSet
Namespace not found	Namespace registry returns not-found	Error propagated; matching never called
Invalid task queue name	task_queue starts with /_sys/	INVALID_ARGUMENT from tqid.NewTaskQueueFamily; matching never called
Root partition	partition_id=0, workflow type	Sends bare name my-queue to matching; returns correct user_data and version
Non-root partition	partition_id=1, workflow type	Sends mangled name /_sys/my-queue/1 to matching
No per-type data	Matching returns response with empty per_type map	user_data is nil; version still populated
Matching error	Matching client returns error	Error propagated to caller

Functional tests

Test	Setup	What it verifies
TestAdminGetTaskQueueUserData_RootPartition	Write fairness weight config to a workflow task queue	Admin RPC resolves namespace by name, routes to root partition (partition_id=0), returns version > 0 and non-nil per-type data
TestAdminGetTaskQueueUserData_NonRootPartition	Same write, then poll until non-root partition replicates	Admin RPC routes to a non-root partition (partition_id=1) via mangled name, returns the same version as root after replication

Manual tests

Setup

1. Build and start the server: make temporal-server && make start-sqlite
2. Create namespace: temporal operator namespace create default
3. Insert assignment rule: temporal task-queue versioning insert-assignment-rule

Case 1 — Root partition, workflow type

grpcurl -plaintext \
  -d '{"namespace":"default","task_queue":"my-queue","task_queue_type":"TASK_QUEUE_TYPE_WORKFLOW"}' \
  localhost:7233 \
  temporal.server.api.adminservice.v1.AdminService/GetTaskQueueUserData

{
  "version": "1"
}

Case 2 — Root partition, activity type

grpcurl -plaintext \
  -d '{"namespace":"default","task_queue":"my-queue","task_queue_type":"TASK_QUEUE_TYPE_ACTIVITY"}' \
  localhost:7233 \
  temporal.server.api.adminservice.v1.AdminService/GetTaskQueueUserData

{
  "version": "1"
}

Case 3 — Non-root partition, workflow type

grpcurl -plaintext \
  -d '{"namespace":"default","task_queue":"my-queue","task_queue_type":"TASK_QUEUE_TYPE_WORKFLOW","partition_id":1}' \
  localhost:7233 \
  temporal.server.api.adminservice.v1.AdminService/GetTaskQueueUserData

{
  "version": "1"
}

Case 4 — Non-root partition, activity type

grpcurl -plaintext \
  -d '{"namespace":"default","task_queue":"my-queue","task_queue_type":"TASK_QUEUE_TYPE_ACTIVITY","partition_id":1}' \
  localhost:7233 \
  temporal.server.api.adminservice.v1.AdminService/GetTaskQueueUserData

{
  "version": "1"
}

Case 5 — Non-root partition, activity type, with user data

Setup: Add rate limit config

grpcurl -plaintext \
  -d '{
    "namespace": "default",
    "task_queue": "my-queue",
    "task_queue_type": "TASK_QUEUE_TYPE_ACTIVITY",
    "update_queue_rate_limit": {
      "rate_limit": {
        "requests_per_second": 50.0
      },
      "reason": "manual test"
    }
  }' \
  localhost:7233 \
  temporal.api.workflowservice.v1.WorkflowService/UpdateTaskQueueConfig

grpcurl -plaintext \
  -d '{
    "namespace": "default",
    "task_queue": "my-queue",
    "task_queue_type": "TASK_QUEUE_TYPE_ACTIVITY"
  }' \
  localhost:7233 \
  temporal.server.api.adminservice.v1.AdminService/GetTaskQueueUserData

{
  "userData": {
    "config": {
      "queueRateLimit": {
        "rateLimit": {
          "requestsPerSecond": 50
        },
        "metadata": {
          "reason": "manual test",
          "updateTime": "2026-04-13T21:40:39.888Z"
        }
      }
    }
  },
  "version": "2"
}

Case 6 — Namespace not found

grpcurl -plaintext \
  -d '{"namespace":"nonexistent","task_queue":"my-queue","task_queue_type":"TASK_QUEUE_TYPE_WORKFLOW"}' \
  localhost:7233 \
  temporal.server.api.adminservice.v1.AdminService/GetTaskQueueUserData

ERROR:
  Code: NotFound
  Message: Namespace nonexistent is not found.

NOT_FOUND from namespace registry; matching never called.

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