Nexus Standalone: wire up by stephanos · Pull Request #9837 · temporalio/temporal

stephanos · 2026-04-07T03:46:33Z

What changed?

Wire up Nexus Standalone with CHASM.

How did you test it?

stephanos · 2026-04-08T21:59:28Z

 	})

 	t.Run("ReturnsLastAttemptFailure", func(t *testing.T) {
-		t.Skip("Enable once standalone Nexus task and cancellation executors are wired through public Nexus task APIs")


Removed this (was slightly mislabelled)

stephanos · 2026-04-08T22:00:06Z


 		for _, tc := range testCases {
 			t.Run(tc.name, func(t *testing.T) {
-				t.Skip("Enable once standalone Nexus task and cancellation executors are wired through public Nexus task APIs")


Removed this (was slightly mislabelled)

stephanos · 2026-04-14T00:16:48Z

+				},
+				expectedStatus:         enumspb.NEXUS_OPERATION_EXECUTION_STATUS_CANCELED,
+				expectedFailureMessage: "cancel failure",
+			},


New test since cancellation is in now

stephanos · 2026-04-14T00:19:48Z

+		if o.Status == nexusoperationpb.OPERATION_STATUS_TIMED_OUT && o.LastAttemptFailure != nil {
+			return nil, o.LastAttemptFailure
+		}


This is the special case added here

If the operation fails with a timeout error, we still have the last attempt failure in the describe response, but that's different from the cause of the operation failure.

I must have misunderstood our standup conversation about this from a while ago; I'll remove it.

stephanos · 2026-04-14T02:03:21Z

+		return nil, err
+	}
+	return commonnexus.NexusFailureToTemporalFailure(nexusFailure)
+}


NexusTestEnv has a helper for this but the test hasn't been converted to use it yet; follow up ...

stephanos · 2026-04-14T02:13:23Z


 message StartNexusOperationRequest {
  string namespace_id = 1;
+  string endpoint_id = 2;


"breaking change"

Add API boilerplate for standalone Nexus Operations. - [x] built - [ ] run locally and tested manually - [x] covered by existing tests - [ ] added new unit test(s) - [ ] added new functional test(s)

Add Nexus Standalone feature flag. Tests will be added to respective API impl.

Add Nexus Standalone Describe and Start handlers. - [ ] built - [ ] run locally and tested manually - [ ] covered by existing tests - [x] added new unit test(s) - [x] added new functional test(s) --------- Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Add Nexus Standalone List and Count handlers. - [ ] built - [ ] run locally and tested manually - [ ] covered by existing tests - [ ] added new unit test(s) - [x] added new functional test(s)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bergundy · 2026-04-16T19:54:38Z

+
+	switch {
+	case !hasOutcome:
+		return nil, o.LastAttemptFailure


My only concern with how the code is structured is that it assumes that the caller of this function checked that the operation is closed already. Otherwise the last attempt as outcome would be incorrect.

The method had that issue before this refactor, right (it fell back to o.LastAttemptFailure)?

But I agree, that seems wrong - I'll make it return nil instead.

This originated in SAA; I see the outcome method there falls back to LastAttempt if there is no success/failure - but only if it's closed. I wonder what the use case is.

Do you think it's safe to assume that a closed operation will always have success/failure outcome set? Or do we need the fallback to LastAttemptFailure like SAA has?

We need to fallback to LastAttemptFailure. My point was about the function should be self-contained and not make an assumption on how it is called.

bergundy · 2026-04-16T20:01:23Z

+		if o.Status == nexusoperationpb.OPERATION_STATUS_TIMED_OUT && o.LastAttemptFailure != nil {
+			return nil, o.LastAttemptFailure
+		}


If the operation fails with a timeout error, we still have the last attempt failure in the describe response, but that's different from the cause of the operation failure.

bergundy · 2026-04-16T20:03:59Z

+
+		// Result is set by standalone operations. Workflow-attached operations store
+		// the result in the history event and remove the operation after this transition.
+		if event.Result != nil {


We can just always pass in the result IMHO. It doesn't matter for workflow operations since the operation would be immediately deleted from the tree and not take up any additional storage.

(which would make this if redundant)

bergundy · 2026-04-16T20:22:31Z

+		// Result is set by standalone operations. Workflow-attached operations store
+		// the result in the history event and remove the operation after this transition.
+		if event.Result != nil {
+			o.outcome(ctx).Variant = &nexusoperationpb.OperationOutcome_Successful_{


Maybe call outcome() getOrCreateOutcome() to clarify that this is what happens under the hood?

bergundy · 2026-04-16T20:24:22Z

 	}

+	var links []nexus.Link
+	if args.nexusLink != (nexus.Link{}) {


I would just make args.nexusLinks plural and not deal with the empty state. Also there should always be a link, so not sure why this line is needed.

bergundy · 2026-04-16T20:25:08Z


 message StartNexusOperationRequest {
  string namespace_id = 1;
+  string endpoint_id = 2;


Co-authored-by: Roey Berman <roey@temporal.io>

bergundy

Very close now. The comments are blocking but I trust you to merge only after addressing.

bergundy · 2026-04-18T19:01:34Z

You are missing populating a link for the standalone nexus operation. You need to generate a link in this format in loadStartArgs:

// A link to a standalone Nexus operation. message NexusOperation { string namespace = 1; string operation_id = 2; string run_id = 3; }

bergundy · 2026-04-18T19:03:23Z

+
+		// Result is set by standalone operations. Workflow-attached operations store
+		// the result in the history event and remove the operation after this transition.
+		if event.Result != nil {


(which would make this if redundant)

bergundy · 2026-04-18T19:04:39Z

 	})
+}
+
+func TestDescribeOutcome(t *testing.T) {


You need a test for when we use the last attempt failure instead of the outcome field.

@bergundy confused about this one; I had removed (dccc430) the "return last attempt failure as outcome" behavior entirely based on the first review comment.

I'll merge for now to unblock us but happy to address this as a follow-up.

I clarified the comment above.

…tephanos/ns-standalone-wire-up

stephanos force-pushed the stephanos/ns-standalone-wire-up branch from 2253f0c to b503714 Compare April 7, 2026 03:46

stephanos changed the title ~~Stephanos/ns standalone wire up~~ Nexus Standalone: wire up Apr 7, 2026

stephanos force-pushed the feature/nexus-standalone branch 2 times, most recently from 10d3595 to 83bfb53 Compare April 7, 2026 20:38

stephanos force-pushed the stephanos/ns-standalone-wire-up branch from b503714 to 56c2d98 Compare April 7, 2026 20:59

stephanos force-pushed the feature/nexus-standalone branch from 83bfb53 to 6a0bd6e Compare April 8, 2026 18:31

stephanos force-pushed the stephanos/ns-standalone-wire-up branch from 56c2d98 to 517d0bc Compare April 8, 2026 18:58

stephanos force-pushed the feature/nexus-standalone branch from 6a0bd6e to 88281af Compare April 8, 2026 19:17

stephanos force-pushed the stephanos/ns-standalone-wire-up branch 2 times, most recently from f69fecd to 7094ffa Compare April 8, 2026 21:52

stephanos commented Apr 8, 2026

View reviewed changes

stephanos force-pushed the stephanos/ns-standalone-wire-up branch 18 times, most recently from 470834e to 643f340 Compare April 9, 2026 03:31

stephanos force-pushed the feature/nexus-standalone branch from 22ed5f4 to 8b51e02 Compare April 13, 2026 19:48

stephanos force-pushed the stephanos/ns-standalone-wire-up branch from b936601 to 103b0e1 Compare April 13, 2026 20:29

stephanos force-pushed the feature/nexus-standalone branch from 8b51e02 to d13cafb Compare April 13, 2026 20:51

stephanos commented Apr 14, 2026

View reviewed changes

stephanos and others added 12 commits April 14, 2026 13:25

Standalone Nexus Operations API (#9458)

d641672

Add API boilerplate for standalone Nexus Operations. - [x] built - [ ] run locally and tested manually - [x] covered by existing tests - [ ] added new unit test(s) - [ ] added new functional test(s)

Nexus Standalone: Feature flag (#9567)

0f453f0

Add Nexus Standalone feature flag. Tests will be added to respective API impl.

Nexus Standalone: List + Count (#9559)

963d19c

Add Nexus Standalone List and Count handlers. - [ ] built - [ ] run locally and tested manually - [ ] covered by existing tests - [ ] added new unit test(s) - [x] added new functional test(s)

Nexus Standalone: Terminate + Cancel (#9624)

147664d

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Nexus Standalone: Delete (#9654)

f2397f4

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Nexus Standalone: Poll (#9780)

74205f2

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Fix nexusoperation after main rebase

c95b075

Clean go.sum after api update

06c514c

Nexus Standalone: translate already started err

b1edca1

Nexus CHASM async completion

aec2bf4

Nexus Standalone: wire up

d0e561a

bergundy reviewed Apr 16, 2026

View reviewed changes

stephanos and others added 6 commits April 17, 2026 09:07

60s long poll

512eff6

Co-authored-by: Roey Berman <roey@temporal.io>

plural nexus link

1b3c5aa

getOrCreateOutcome

5ac1c1a

event.Result

2257100

remove LastAttemptFailure

dccc430

isClosed guard

4927048

bergundy approved these changes Apr 18, 2026

View reviewed changes

stephanos added 3 commits April 21, 2026 14:12

drop if event.Result != nil

474d318

NexusLink

9edcb10

Merge remote-tracking branch 'origin/feature/nexus-standalone' into s…

ac606e1

…tephanos/ns-standalone-wire-up

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