[workflows-shared] Add full step output retrieval to Workflows local explorer by pombosilva · Pull Request #14822 · cloudflare/workers-sdk

pombosilva · 2026-07-23T17:04:51Z

Fixes WOR-1510.

Adds a GET /workflows/{workflow_name}/instances/{instance_id}/step that returns a step's complete, untruncated output, serving ReadableStream outputs as raw application/octet-stream bytes, which the explorer UI fetches on demand when a step's inline preview was truncated.

Tests
- Tests included/updated
- Automated tests not possible - manual testing has been completed as follows:
- Additional testing not necessary because:
Public documentation
- Cloudflare docs PR(s):
- Documentation not necessary because: just adds a missing feature to local explorer

A picture of a cute animal (not mandatory, but encouraged)

changeset-bot · 2026-07-23T17:04:59Z

🦋 Changeset detected

Latest commit: bef29ae

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 8 packages

Name	Type
miniflare	Minor
@cloudflare/deploy-helpers	Patch
@cloudflare/pages-shared	Patch
@cloudflare/remote-bindings	Patch
@cloudflare/runtime-types	Patch
@cloudflare/vite-plugin	Patch
@cloudflare/vitest-pool-workers	Patch
wrangler	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

…explorer

github-actions · 2026-07-24T07:55:25Z

✅ All changesets look good

pkg-pr-new · 2026-07-24T07:58:01Z

@cloudflare/autoconfig

npm i https://pkg.pr.new/@cloudflare/autoconfig@14822

@cloudflare/config

npm i https://pkg.pr.new/@cloudflare/config@14822

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@14822

@cloudflare/deploy-helpers

npm i https://pkg.pr.new/@cloudflare/deploy-helpers@14822

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@14822

miniflare

npm i https://pkg.pr.new/miniflare@14822

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@14822

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@14822

@cloudflare/vite-plugin

npm i https://pkg.pr.new/@cloudflare/vite-plugin@14822

@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@14822

@cloudflare/workers-auth

npm i https://pkg.pr.new/@cloudflare/workers-auth@14822

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@14822

@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@14822

wrangler

npm i https://pkg.pr.new/wrangler@14822

commit: bef29ae

workers-devprod · 2026-07-24T08:36:49Z

Codeowners approval required for this PR:

@cloudflare/workflows
✅ @cloudflare/wrangler

Show detailed file reviewers

packages/workflows-shared/src/engine.ts: [@cloudflare/workflows]
packages/workflows-shared/tests/engine.test.ts: [@cloudflare/workflows]
packages/workflows-shared/tests/utils.ts: [@cloudflare/workflows]

devin-ai-integration

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

pombosilva · 2026-07-24T08:45:16Z

/bonk

ask-bonk · 2026-07-24T08:50:28Z

/bonk review — PR #14822

Reviewed the full stack of this change (engine → miniflare resource → OpenAPI/generated client → explorer UI). Summary: the implementation is correct, well-layered, and matches the local-explorer conventions. I verified locally and found no changes required.

What I checked

Engine (getStepOutput) — packages/workflows-shared/src/engine.ts:570
- Correctly resolves the step's groupKey from STEP_START/WAIT_START, then reconstructs status from the group's events.
- Streamed outputs are replayed via replayStreamFromMeta() (integrity-checked, only when Complete) and returned as a ReadableStream; non-stream outputs fall back to metadata.result.
- attempt handling is sound: ATTEMPT_FAILURE → errored with that attempt's error; in-flight (ATTEMPT_START only) → running; successful attempt correctly falls through to the shared stored value.
- waitForEvent maps WAIT_COMPLETE → payload, WAIT_TIMED_OUT → errored, else waiting.
Miniflare resource — packages/miniflare/src/workers/local-explorer/resources/workflows.ts:797
- ReadableStream outputs are streamed back as application/octet-stream; JSON otherwise via wrapResponse().
- Error mapping (step_not_found → 404, not_found/"Engine was never started" → 404, else 500) is consistent with the existing instance-details handler.
- The attempt + waitForEvent combination is rejected with a 400 before hitting the DO.
- Cross-instance forwarding via findWorkflowOwner() + fetchFromPeer() preserves the raw (including octet-stream) body.
- Nice cleanup extracting resolveEngineStub() and deduplicating the hex-vs-name DO id logic.
OpenAPI + generated client — spec added in openapi-filter-config.ts; types.gen.ts/zod.gen.ts/index.ts are consistent with it. validateQuery() coerces the string attempt param to a number, so the z.number() schema validates correctly.
UI — StepRow.tsx lazily fetches the full output only when the inline preview is a truncated stream preview (isTruncatedStreamPreview), decodes UTF-8 with a base64 fallback for binary, and cancels via an active flag on unmount. CopyButton disabled state and loading UI look right.

Verification run locally

pnpm -F @cloudflare/workflows-shared test:ci → 154 passed (incl. the 5 new getStepOutput cases). The boom/step-boom uncaught-exception log lines are expected from the failure-path tests.
pnpm -F @cloudflare/workflows-shared check:type → clean.

Minor, non-blocking notes (no action needed):

The OpenAPI attempt param declares exclusiveMinimum: 0, but generated zod is z.number().int() (codegen drops the bound). The handler doesn't rely on it, so it's cosmetic.
No miniflare-layer .spec.ts covers getWorkflowStepOutput (octet-stream response, 400 for attempt+waitForEvent, peer forwarding). The engine layer is well covered; a resource-level spec would be a nice future addition but isn't required given there's no existing workflows spec file.

LGTM. 🔨

ask-bonk · 2026-07-24T08:50:39Z

Posted my review on PR #14822.

Summary

@pombosilva invoked /bonk — a request to thoroughly review the PR. I reviewed the full stack of PR #14822 ("Add full step output retrieval to Workflows local explorer") across all layers and verified it locally.

Findings: the implementation is correct and no code changes were needed.

What I verified:

Engine (getStepOutput in engine.ts:570): correct group-key resolution, stream replay with integrity checks, sound attempt/waitForEvent/failure status mapping.
Miniflare resource (workflows.ts:797): octet-stream vs JSON responses, consistent error→HTTP mapping, the 400 guard for attempt+waitForEvent, and cross-instance peer forwarding that preserves raw bodies. Also a clean resolveEngineStub() refactor.
OpenAPI + generated client: spec and generated types.gen.ts/zod.gen.ts/index.ts are consistent; validateQuery coerces the string attempt param.
UI (StepRow.tsx): lazy full-output fetch only on truncated previews, UTF-8 decode with base64 fallback, proper unmount cancellation.

Verification:

pnpm -F @cloudflare/workflows-shared test:ci → 154 passed (incl. 5 new getStepOutput tests)
pnpm -F @cloudflare/workflows-shared check:type → clean

I noted two minor non-blocking observations (a cosmetic codegen gap on the attempt bound, and the absence of a miniflare-layer spec for the resource handler) but neither warrants changes. LGTM.

github run

vaishnav-mk · 2026-07-24T10:35:05Z

+		return () => {
+			active = false;
+		};
+	}, [needsFetch, workflowName, instanceId, step.name]);


i think restart from step can display stale output? it omits step output/version

vaishnav-mk · 2026-07-24T10:36:57Z

+		}
+		let active = true;
+		setState({ status: "loading" });
+		void workflowsGetStepOutput({


do you think 1gb of download all at once would crash the tab?

dario-piotrowicz

LGTM with a couple of minor suggestions 🙂

dario-piotrowicz · 2026-07-24T10:25:17Z

+	return (
+		typeof value === "string" &&
+		(value.endsWith(STREAM_PREVIEW_TRUNCATED_MARKER) ||
+			value.startsWith("[ReadableStream"))


Nit: I think a regex would be more correct here?

Suggested change

value.startsWith("[ReadableStream"))

/^\[ReadableStream:\s\d+\s\w+]$/.test(value)

(Then we can also have some other tests that make sure that incorrect string starting with [ReadableStream are not accepted)

[workflows-shared] Add full step output retrieval to Workflows local …

bef29ae

…explorer

pombosilva force-pushed the workflows-local-explorer-step-output branch from 943ca72 to bef29ae Compare July 24, 2026 07:54

workers-devprod added this to workers-sdk Jul 24, 2026

github-project-automation Bot moved this to Untriaged in workers-sdk Jul 24, 2026

pombosilva marked this pull request as ready for review July 24, 2026 08:36

pombosilva requested a review from workers-devprod as a code owner July 24, 2026 08:36

workers-devprod requested review from a team and dario-piotrowicz and removed request for a team July 24, 2026 08:36

devin-ai-integration Bot reviewed Jul 24, 2026

View reviewed changes

vaishnav-mk reviewed Jul 24, 2026

View reviewed changes

dario-piotrowicz approved these changes Jul 24, 2026

View reviewed changes

	value.startsWith("[ReadableStream"))
	/^\[ReadableStream:\s\d+\s\w+]$/.test(value)

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✅ Devin Review: No Issues Found

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pombosilva commented Jul 24, 2026

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ask-bonk Bot commented Jul 24, 2026

/bonk review — PR #14822

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vaishnav-mk Jul 24, 2026

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pombosilva commented Jul 23, 2026 •

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