feat: Adds tdbg migration script to power migrations via visibility by davidporter-id-au · Pull Request #10495 · temporalio/temporal

davidporter-id-au · 2026-06-02T22:37:37Z

What changed?

Adds a cli set of flags to the tdbg schedule migrate subcommand, to fetch from visibility (or stdin) and perform a migration.

Using Visibility

tdbg schedule migrate --target chasm --from-visibility
[dry-run] would migrate default/verify-sa-1780095016 -> chasm
Dry-run: 1 schedule(s) would be migrated. Re-run with --execute to perform.

tdbg --namespace default schedule migrate --target workflow  --from-visibility --execute
migrated default/verify-sa-1780095016 -> workflow
Done: 1 migrated, 0 failed (of 1).

Using stdin:

./tdbg schedule migrate --target chasm --from-visibility --output-log target.log
[dry-run] would migrate default/schedule-6 -> chasm
[dry-run] would migrate default/schedule-5 -> chasm
[dry-run] would migrate default/schedule-4 -> chasm
...
[dry-run] would migrate default/schedule-8 -> chasm
[dry-run] would migrate default/schedule-7 -> chasm
[dry-run] would migrate default/YourScheduleId-5 -> chasm
Dry-run: 20 schedule(s) would be migrated. Re-run with --execute to perform.
➜  temporal git:(bugfix/handling-list-with-migration-problems) ✗ head target.log
{"timestamp":"2026-06-05T06:41:27Z","namespace":"default","schedule_id":"schedule-6","target":"chasm","status":"dry-run"}
{"timestamp":"2026-06-05T06:41:27Z","namespace":"default","schedule_id":"schedule-5","target":"chasm","status":"dry-run"}
{"timestamp":"2026-06-05T06:41:27Z","namespace":"default","schedule_id":"schedule-
....
8","target":"chasm","status":"dry-run"}
{"timestamp":"2026-06-05T06:41:27Z","namespace":"default","schedule_id":"YourScheduleId-7","target":"chasm","status":"dry-run"}
➜  temporal git:(bugfix/handling-list-with-migration-problems) ✗ cat target.log | ./tdbg schedule migrate --target chasm
[dry-run] would migrate default/schedule-6 -> chasm
[dry-run] would migrate default/schedule-5 -> chasm
[dry-run] would migrate default/schedule-4 -> chasm
[dry-run] would migrate default/schedule-3 -> chasm
[dry-run] would migrate default/schedule-2 -> chasm
...
[dry-run] would migrate default/schedule-8 -> chasm
[dry-run] would migrate default/schedule-7 -> chasm
[dry-run] would migrate default/YourScheduleId-5 -> chasm
Dry-run: 20 schedule(s) would be migrated. Re-run with --execute to perform.

Why?

Temporal is moving to a V2/Chasm based scheduler. Migrating schedules manually is easier when done via visibility, so this is a hopefully more ergonomic set of commands for such a migration:

How did you test it?

Potential risks

Not likely to be a lot relating to the tool itself, the migration path probably needs a bit more testing through.

chaptersix · 2026-06-05T18:52:45Z

The two full queries used are:

- Workflow-backed / V1:
  `TemporalNamespaceDivision = 'TemporalScheduler' AND ExecutionStatus = 'Running'`

- CHASM / V2:
  `TemporalNamespaceDivision = '403648407' AND ExecutionStatus = 'Running'`

`403648407` is the farmhash fingerprint32 of `scheduler.scheduler`.

chaptersix

Review of the tdbg bulk migration changes. Overall looks solid -- nice dry-run default and structured logging. A few issues around flag validation and the default visibility query direction.

chaptersix · 2026-06-05T19:05:08Z

+		if err != nil {
+			return fmt.Errorf("unable to open output log %q: %w", logPath, err)
+		}
+		defer func() { _ = logFile.Close() }()


If ListWorkflowExecutions fails mid-pagination, workers may have already migrated some schedules, but summary.print is never called -- the user has no idea what already happened. Move summary.print(c, execute) before the listErr check so partial progress is always reported.

chaptersix · 2026-06-05T19:05:08Z

+		if len(nextPageToken) == 0 {
+			break
+		}
 	}


--output-log is silently ignored in stdin mode -- the migrateSummary is created without wiring up logEnc from FlagOutputLog. Either handle it here too, or reject the flag combination.

I think this now addressed with some validation at the top of the function

chaptersix · 2026-06-05T19:05:08Z

+	var listErr error
+	var nextPageToken []byte
+	for {
+		ctx, cancel := newContext(c)


--workers is also silently ignored in stdin mode (processes sequentially). Consider either applying the worker pool here too, or validating that --workers isn't set when using stdin.

now returns an error

Also, not sure if this comment was from an earlier line, it seems misaligned? no big deal either way

chaptersix · 2026-06-05T19:05:08Z

+				&cli.BoolFlag{
+					Name:  FlagExecute,
+					Usage: "Perform the migration. Without this flag, --from-visibility and stdin modes only print what they would do (dry-run)",
+				},


--query is accepted without --from-visibility and silently ignored (both in --schedule-id and stdin modes). Worth validating the combination up front.

I think tihs is addressed now

chaptersix · 2026-06-05T19:05:08Z

+	os.Stdin = f
+	defer func() {
+		os.Stdin = orig
+		_ = f.Close()


nit: withStdin mutates os.Stdin which is process-global. Worth a comment that these tests must not use t.Parallel().

Yeah, this one annoyed me. I was considering a larger refactor to fix but it got out of hand. Imho it'd be better to pass the os.ReadWriter interface down rather than just reaching in to Os.Stdin like this

chaptersix · 2026-06-05T19:06:53Z

The two full queries used are:

- Workflow-backed / V1:
  `TemporalNamespaceDivision = 'TemporalScheduler' AND ExecutionStatus = 'Running'`

- CHASM / V2:
  `TemporalNamespaceDivision = '403648407' AND ExecutionStatus = 'Running'`

`403648407` is the farmhash fingerprint32 of `scheduler.scheduler`.

would be great to add this to the help text

davidporter-id-au added 3 commits June 2, 2026 14:57

migration script

42a78f7

Merge branch 'main' into feature/adding-fast-migration

11c4580

lint

26bfb0d

davidporter-id-au changed the title ~~migration script~~ feat: Adds tdbg migration script to power migrations via visibility Jun 5, 2026

lint

f63b002

davidporter-id-au requested review from chaptersix and lina-temporal June 5, 2026 06:52

davidporter-id-au marked this pull request as ready for review June 5, 2026 06:52

davidporter-id-au requested a review from a team as a code owner June 5, 2026 06:52

chaptersix reviewed Jun 5, 2026

View reviewed changes

davidporter-id-au added 4 commits June 5, 2026 13:07

Feedback/fix

a4cc287

Merge branch 'main' into feature/adding-fast-migration

25588b2

feedback 2

739ba3a

Merge branch 'main' into feature/adding-fast-migration

7e5f39b

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davidporter-id-au commented Jun 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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davidporter-id-au Jun 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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chaptersix commented Jun 5, 2026

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davidporter-id-au commented Jun 2, 2026 •

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davidporter-id-au Jun 17, 2026 •

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