List and describe workers natively, and release a replaced worker's activity leases

.github/workflows/server-parity.yml

@@ -24,6 +24,8 @@ on:
       - tests/Unit/ServerParityAdmissionContractTest.mjs
       - tests/Unit/ServerParityRoleTokenContractTest.mjs
       - tests/Unit/ServerParityWorkerDeregistrationContractTest.mjs
+      - tests/Unit/ServerParityWorkerListingContractTest.mjs
+      - tests/Unit/ServerParityWorkerReplacementContractTest.mjs
       - tests/Unit/ServerParityWaitingHistoryContractTest.mjs
       - tests/Unit/ServerParityTaskRetryContractTest.mjs
       - tests/Unit/ServerParityPublishedPatchContractTest.mjs
@@ -61,6 +63,8 @@ on:
       - tests/Unit/ServerParityAdmissionContractTest.mjs
       - tests/Unit/ServerParityRoleTokenContractTest.mjs
       - tests/Unit/ServerParityWorkerDeregistrationContractTest.mjs
+      - tests/Unit/ServerParityWorkerListingContractTest.mjs
+      - tests/Unit/ServerParityWorkerReplacementContractTest.mjs
       - tests/Unit/ServerParityWaitingHistoryContractTest.mjs
       - tests/Unit/ServerParityTaskRetryContractTest.mjs
       - tests/Unit/ServerParityPublishedPatchContractTest.mjs
@@ -1420,7 +1424,7 @@ jobs:
             -e COMPOSER_HOME=/tmp/composer -v "$PWD:/source" -w /source "$image" \
             install --working-dir=scripts/conformance/server-parity --no-interaction --no-progress
           docker run --rm --user=1000:1000 --entrypoint node -v "$PWD:/source:ro" -w /source \
-            "$image" --test tests/Unit/ServerParityRunnerTest.mjs tests/Unit/ServerParityCooperativeContractTest.mjs tests/Unit/ServerParityChildCancellationContractTest.mjs tests/Unit/ServerParityScheduleContractTest.mjs tests/Unit/ServerParityVisibilityContractTest.mjs tests/Unit/ServerParityAdmissionContractTest.mjs tests/Unit/ServerParityRoleTokenContractTest.mjs tests/Unit/ServerParityWorkerDeregistrationContractTest.mjs tests/Unit/ServerParityPatchDeploymentContractTest.mjs tests/Unit/ServerParityWaitingHistoryContractTest.mjs tests/Unit/ServerParityTaskRetryContractTest.mjs tests/Unit/ServerParityPublishedPatchContractTest.mjs tests/Unit/ServerParityPublishedPatchTransportTest.mjs tests/Unit/ServerParityRecordFileTest.mjs > parity-evidence/comparator-tests.txt
+            "$image" --test tests/Unit/ServerParityRunnerTest.mjs tests/Unit/ServerParityCooperativeContractTest.mjs tests/Unit/ServerParityChildCancellationContractTest.mjs tests/Unit/ServerParityScheduleContractTest.mjs tests/Unit/ServerParityVisibilityContractTest.mjs tests/Unit/ServerParityAdmissionContractTest.mjs tests/Unit/ServerParityRoleTokenContractTest.mjs tests/Unit/ServerParityWorkerDeregistrationContractTest.mjs tests/Unit/ServerParityWorkerListingContractTest.mjs tests/Unit/ServerParityWorkerReplacementContractTest.mjs tests/Unit/ServerParityPatchDeploymentContractTest.mjs tests/Unit/ServerParityWaitingHistoryContractTest.mjs tests/Unit/ServerParityTaskRetryContractTest.mjs tests/Unit/ServerParityPublishedPatchContractTest.mjs tests/Unit/ServerParityPublishedPatchTransportTest.mjs tests/Unit/ServerParityRecordFileTest.mjs > parity-evidence/comparator-tests.txt
           docker run --rm --user=1000:1000 --cpus=1 --memory=256m --memory-swap=256m \
             --network=none --entrypoint node -v "$PWD:/source:ro" -w /source \
             "$image" --test tests/Unit/ServerParityCodecDeadlineLoadTest.mjs > parity-evidence/codec-load-tests.txt

docs/rust-server-port.md

@@ -14,29 +14,75 @@ qualify a later tree.
 
 ## Current state
 
-Updated October 19, 2026, after merging #460.
-
-- **Merged native slices.** [#478](https://github.com/durable-workflow/server/pull/478)
-  (run observation, timed waits, `all` barriers, terminal update closure and
-  cooperative cancellation with abandoned and independently cancelled
-  children), [#476](https://github.com/durable-workflow/server/pull/476)
-  (run activity metadata listing), [#494](https://github.com/durable-workflow/server/pull/494)
-  (CPU deadline-health observer timing) and [#460](https://github.com/durable-workflow/server/pull/460)
-  (read-only inspection of an existing PHP database). No native PR is open.
-- **Shared-suite reliability.** Each 13-job run still tends to show one
-  intermittent failure in a step its change does not touch, and qualification
-  records classify each one. Diagnosed and corrected: published PHP SQLite
-  reference lock pressure, and CPU observer client timing. Diagnosed, decision
-  pending: the query-authority deadline-boundary replay (see known gaps).
-  Not yet diagnosed: one native-test failure in `execution-and-codec` step 8 on
-  main's post-#478 run, which four local repetitions under the CI limits did
-  not reproduce.
-- **Next action.** Decide the query deadline-boundary replay contract and add
-  its fixture. Then correct native timer dispatch under CPU load with a
-  deadline-health control. Then continue the remaining parity families, the
-  backup-first in-place takeover and the performance baseline on disposable
-  hosts.
-
+Updated October 20, 2026.
+
+- **Merged on October 20.**
+  - [#507](https://github.com/durable-workflow/server/pull/507) gives codec work under the transition lock its own permit.
+  - [#508](https://github.com/durable-workflow/server/pull/508) keeps explicit worker command declarations.
+  - [#509](https://github.com/durable-workflow/server/pull/509) reports poll statuses as the worker protocol does.
+  - [#516](https://github.com/durable-workflow/server/pull/516) lets held long polls wait without the transition lock.
+  - [#517](https://github.com/durable-workflow/server/pull/517) designs the backup-first takeover.
+
+  Main's 13-job parity run passed at `ee88ac6ba`.
+- **Also merged.** [#515](https://github.com/durable-workflow/server/pull/515)
+  retries the PHP reference's lock-pressure refusals in the probes, after
+  passing all 13 parity jobs.
+- **Open, qualifying on main with #515.** Each of these failed or deferred parity only in
+  steps #515 corrects or that it doesn't touch.
+  - The query pair: [#499](https://github.com/durable-workflow/server/pull/499),
+    then [#510](https://github.com/durable-workflow/server/pull/510).
+  - The backup-first takeover stack: [#523](https://github.com/durable-workflow/server/pull/523)
+    (fingerprint), [#529](https://github.com/durable-workflow/server/pull/529)
+    (layouts) and [#532](https://github.com/durable-workflow/server/pull/532),
+    [#533](https://github.com/durable-workflow/server/pull/533) and
+    [#536](https://github.com/durable-workflow/server/pull/536) (SQLite,
+    PostgreSQL and MySQL/MariaDB takeover). Then
+    [#538](https://github.com/durable-workflow/server/pull/538) (SQLite WAL
+    preparation) and [#539](https://github.com/durable-workflow/server/pull/539)
+    (a PHP-accepted signal and an expired PHP lease resumed under native, plus
+    refusal of unsupported features).
+  - Immediate termination, and worker listing with registration facts.
+- **Parity surface.** With this branch, native serves 63 of published PHP's 173 API
+  routes. The missing families are listed below under "API surface still
+  missing".
+- **Next action.** Run parity once on each stack top (#510,
+  #539 and the worker listing branch) and merge each stack. Then port history
+  export, a large bundle the CLI and both SDKs use for replay. Multi-node
+  qualification and packaging the native binary into the server image remain
+  open gates.
+
+## API surface still missing
+
+These published PHP 2.9.8 routes have no native handler yet, by family. The
+CLI and Waterline use the first group.
+
+- **Used by the CLI or Waterline.**
+  - Schedule listing, update and backfill.
+  - Task queues and their build IDs.
+  - Namespace update, delete and external storage.
+  - Search attributes.
+  - `system` repair, retention and activity-timeout passes, metrics and
+    operator dashboards.
+  - Storage test.
+  - Activities (standalone).
+- **Worker protocol features.**
+  - Worker sessions.
+  - Update validation tasks.
+  - Prepared local activities.
+  - Cancellation scopes.
+  - Activity cancellation acknowledgement.
+- **Run operations.**
+  - History export.
+  - Archive.
+  - Redrive.
+  - Imports from embedded v2 and Waterline v1.
+- **Other families.**
+  - Message streams.
+  - Service catalogs and endpoints.
+  - Nexus operations.
+  - Runtime credentials.
+  - Deployments.
+  - Bridge adapters.
 ## Known gaps found in review
 
 These are confirmed differences from the published PHP reference and open
@@ -85,6 +131,11 @@ contract fixture before its correction.
   or whether the fixture counts a boundary replay as the same claim, then add the
   fixture before changing either side.
 
+- **History retention.** Published PHP's worker heartbeat runs an inline
+  history retention pass, and the default namespace retention is bounded at
+  30 days, so PHP prunes old closed runs. Native has no retention yet. Its
+  heartbeat omits PHP's `retention` report rather than claim a pass. The
+  `system/retention` endpoints are absent too.
 - **Python worker shutdown after a late synchronous query handler (not yet
   diagnosed).** In the SQLite query-authority cohort on #515's run
   39431491496, the published Python SDK 2.5.15 client in `late-handler-sync`
@@ -93,6 +144,22 @@ contract fixture before its correction.
   then did not stop within the 5-second shutdown budget. Forty local
   repetitions of that case alone passed. Find what holds the query thread
   after the fence before changing either side.
+- **Workflow definition evolution (PHP main after #525, not yet released).**
+  Current PHP routes a run whose recorded workflow definition is gone to a
+  replacement definition that passes strict replay. It then reports
+  `definition_routing` on task queues and run diagnostics. It also records
+  each worker's protocol version under `_worker_protocol_version` in its
+  stored process metrics. That entry shows up in the worker listing. Native
+  follows the frozen published reference, which has none of this. Port it
+  with its own fixture once it is published.
+- **Trace context (Workflow #773 / workflow#788, not yet published).** A
+  Workflow minor will add nullable `observability_context` columns on runs,
+  commands and tasks, plus an entry in schedule metadata. Native-owned
+  databases are unaffected. A Server release carrying the columns is a new
+  takeover source layout, which native refuses with
+  `upgrade_source_catalog_unqualified` until its recipe lands. The recipe must
+  also refuse rows that carry trace context until native implements the
+  contract. The boundary is agreed on #325.
 - **Terminating a child run.** Published Workflow resolves the parent with
   `ChildRunTerminated` and the `terminated` child call status. Native refuses
   this with `422 termination_propagation_not_available` until the parent-side
@@ -166,6 +233,56 @@ support is not evidence of multi-node safety.
 Newest checkpoints first. Each entry is exact to the source, tree and runs it
 names, including unsuccessful observations.
 
+October 20, worker listing:
+
+- **Source.** Native serves `GET /api/workers` and `GET /api/workers/{id}`,
+  as published PHP's WorkerManagementController does:
+  - the summary fields;
+  - the `task_queue` and `status` filters, with stale workers hidden unless
+    asked for;
+  - the stale window;
+  - `404 worker_not_found`.
+
+  Operators may read these; only `DELETE` needs an admin. Named namespaces may
+  read them.
+- **Registration facts.** Registration and heartbeat now keep what PHP keeps:
+  - capacities, defaulting to 100, 100 and 10;
+  - task slots, bounded by those capacities;
+  - normalized process metrics;
+  - the heartbeat cadence;
+  - workflow definition fingerprints.
+
+  Re-registering an active worker with a changed fingerprint is refused with
+  `409 workflow_definition_changed`. Omitting an advertised one is refused with
+  `409 workflow_definition_fingerprint_missing`, and neither refusal changes
+  the registration. Omitting the fingerprints keeps the advertised one. A
+  heartbeat changes only what it reports. Its acknowledgement carries the
+  configured cadence and stale window.
+- **A replaced worker's activity leases.** A new process registering a
+  worker_id that holds activity leases now releases them at once, as PHP
+  does. Its running attempts close as `expired`, and the tasks return to
+  ready, so the next claim is attempt 2 of the same task. This holds even under
+  a one-attempt retry policy, since PHP checks no policy at claim time. Before
+  this, native left the task leased for the five-minute activity lease. The
+  expired attempt's completion now gets PHP's whole stale receipt:
+  `409 stale_attempt`, `recorded: false`, and the activity, attempt and task
+  statuses.
+- **Fixtures.**
+  - `worker-listing` registers two workers through the unchanged published
+    SDK. It then lists, filters, describes and refuses them, and
+    re-registers and deregisters them.
+  - `worker-replacement-activity-lease` replaces a worker holding an activity
+    lease, then completes the original and the replacement attempts.
+
+  The contracts check each HTTP target against the reviewed facts. Embedded
+  mode is explicitly inapplicable.
+- **Local evidence.** A local copy of the SQLite parity step recorded
+  published PHP 2.5.14, embedded PHP and native for both fixtures and
+  `namespace-isolation`. All three targets passed and the comparison passed.
+  Before the release, native failed the replacement fixture: its second claim
+  found no task. Native integration tests pass on SQLite, PostgreSQL, MySQL
+  and MariaDB.
+
 October 20, immediate termination:
 
 - **Source.** Native serves `POST /api/workflows/{id}/terminate` and its

rust/src/runtime/execution.rs

@@ -705,8 +705,38 @@ impl Runtime {
             page_size: i64,
         ) -> Result<Value>
     );
-    delegate!(register(body: Value) -> Result<Value>);
-    delegate!(worker_heartbeat(body: Value) -> Result<Value>);
+    pub(crate) async fn register(&self, body: Value) -> Result<Value> {
+        match &*self.storage {
+            Storage::Sqlite(store) => store.register(body, &self.queries).await,
+            Storage::Postgres(store) => store.register(body, &self.queries).await,
+            Storage::MySql(store) => store.register(body, &self.queries).await,
+        }
+    }
+    pub(crate) async fn worker_heartbeat(&self, body: Value) -> Result<Value> {
+        match &*self.storage {
+            Storage::Sqlite(store) => store.worker_heartbeat(body, &self.queries).await,
+            Storage::Postgres(store) => store.worker_heartbeat(body, &self.queries).await,
+            Storage::MySql(store) => store.worker_heartbeat(body, &self.queries).await,
+        }
+    }
+    pub(crate) async fn list_workers(
+        &self,
+        task_queue: Option<&str>,
+        status: Option<&str>,
+    ) -> Result<Value> {
+        match &*self.storage {
+            Storage::Sqlite(store) => store.list_workers(task_queue, status, &self.queries).await,
+            Storage::Postgres(store) => store.list_workers(task_queue, status, &self.queries).await,
+            Storage::MySql(store) => store.list_workers(task_queue, status, &self.queries).await,
+        }
+    }
+    pub(crate) async fn describe_worker(&self, worker_id: &str) -> Result<Value> {
+        match &*self.storage {
+            Storage::Sqlite(store) => store.describe_worker(worker_id, &self.queries).await,
+            Storage::Postgres(store) => store.describe_worker(worker_id, &self.queries).await,
+            Storage::MySql(store) => store.describe_worker(worker_id, &self.queries).await,
+        }
+    }
     delegate!(deregister(worker_id: &str) -> Result<Value>);
     pub(crate) async fn deregister_fenced(&self, worker_id: &str, body: Value) -> Result<Value> {
         let codec = self.transition_codec.clone();

rust/src/runtime/http.rs

@@ -152,7 +152,11 @@ pub fn router(runtime: Runtime) -> Router {
             "/api/worker/registrations/{worker_id}/deregister",
             post(deregister_fenced),
         )
-        .route("/api/workers/{worker_id}", delete(deregister))
+        .route("/api/workers", get(list_workers))
+        .route(
+            "/api/workers/{worker_id}",
+            get(describe_worker).delete(deregister),
+        )
         .route("/api/worker/workflow-tasks/poll", post(poll_workflow))
         .route(
             "/api/worker/workflow-tasks/{task_id}/deliver-cancellation",
@@ -274,7 +278,7 @@ async fn guard(State(runtime): State<Runtime>, mut request: Request, next: Next)
         &["worker", "operator", "admin"]
     } else if worker {
         &["worker"]
-    } else if path.starts_with("/api/workers/")
+    } else if path.starts_with("/api/workers/") && request.method() != Method::GET
         || path == "/api/namespaces" && request.method() == Method::POST
         || path.starts_with("/api/namespaces/")
             && path.ends_with("/external-storage")
@@ -413,6 +417,13 @@ fn named_namespace_operation(method: &str, path: &str) -> bool {
     if path == "/api/workflows" {
         return method == "POST";
     }
+    if path == "/api/workers"
+        || path
+            .strip_prefix("/api/workers/")
+            .is_some_and(|id| !id.is_empty() && !id.contains('/'))
+    {
+        return method == "GET";
+    }
     if let Some(path) = path.strip_prefix("/api/workflows/") {
         let parts: Vec<_> = path.split('/').collect();
         if matches!(
@@ -932,6 +943,24 @@ async fn worker_heartbeat(
 ) -> Result<Json<Value>> {
     runtime.worker_heartbeat(body).await.map(Json)
 }
+async fn list_workers(
+    Extension(runtime): Extension<Runtime>,
+    Query(query): Query<std::collections::HashMap<String, String>>,
+) -> Result<Json<Value>> {
+    runtime
+        .list_workers(
+            query.get("task_queue").map(String::as_str),
+            query.get("status").map(String::as_str),
+        )
+        .await
+        .map(Json)
+}
+async fn describe_worker(
+    Extension(runtime): Extension<Runtime>,
+    Path(worker_id): Path<String>,
+) -> Result<Json<Value>> {
+    runtime.describe_worker(&worker_id).await.map(Json)
+}
 async fn deregister(
     Extension(runtime): Extension<Runtime>,
     Path(worker_id): Path<String>,

rust/src/runtime/memos.rs

@@ -427,7 +427,7 @@ mod tests {
                 .unwrap(),
         );
         store.register(json!({"worker_id":"memo-unit-worker", "task_queue":"test", "runtime":"php",
-            "supported_workflow_types":["echo"], "supported_activity_types":[], "capabilities":["memo_upserts"]})).await.unwrap();
+            "supported_workflow_types":["echo"], "supported_activity_types":[], "capabilities":["memo_upserts"]}), &crate::runtime::QueryTaskConfig::default()).await.unwrap();
         let original = store
             .start(
                 json!({"workflow_id":"memo-unit", "workflow_type":"echo", "task_queue":"test",

rust/src/runtime/mod.rs

@@ -34,8 +34,8 @@ mod memo_limits;
 mod memos;
 pub mod mysql;
 mod namespaces;
-pub mod postgres;
 mod poll_readiness;
+pub mod postgres;
 mod previews;
 mod queries;
 mod query_authority;
@@ -66,6 +66,7 @@ mod wait_projection;
 mod wait_timeouts;
 mod worker_contracts;
 mod worker_incarnations;
+mod worker_management;
 mod workflow_failures;
 
 pub use execution::Runtime;

rust/src/runtime/query_authority.rs

@@ -13,6 +13,8 @@ pub struct QueryTaskConfig {
     pub lease_timeout_seconds: i64,
     pub receipt_ttl_seconds: i64,
     pub worker_stale_after_seconds: i64,
+    /// The worker heartbeat cadence advertised on registration and heartbeat.
+    pub worker_heartbeat_interval_seconds: i64,
     pub poll_timeout_seconds: i64,
 }
 
@@ -23,6 +25,7 @@ impl Default for QueryTaskConfig {
             lease_timeout_seconds: 60,
             receipt_ttl_seconds: 180,
             worker_stale_after_seconds: 30,
+            worker_heartbeat_interval_seconds: 10,
             poll_timeout_seconds: 5,
         }
     }
@@ -85,6 +88,8 @@ impl QueryTaskConfig {
                 heartbeat.saturating_mul(3).max(30),
             )?
             .max(1),
+            // PHP clamps the advertised cadence to one second through an hour.
+            worker_heartbeat_interval_seconds: heartbeat.clamp(1, 3600),
             poll_timeout_seconds: integer(
                 "DW_QUERY_TASK_POLL_TIMEOUT",
                 "WORKFLOW_SERVER_QUERY_TASK_POLL_TIMEOUT",