feat(tasks): expose resume-chain presigned log urls on run detail

[charlesvien]

Problem

Clients bootstrap a task run's session history through the paginated session_logs/ endpoint. Every page re-downloads the run's entire log chain from S3 and re-parses every JSONL line just to slice out ~2 MB, so one cold load of a run with N bytes of history costs O(N²). Once a single page crosses the client's fetch timeout, the run becomes unloadable: retry restarts at offset 0 and dies the same way.

The run detail response already exposes a presigned log_url, but only for the run's own log, not its resume ancestors, so clients can't fetch the full history from object storage directly.

Changes

• Add log_urls to the run detail response: presigned S3 URLs for every JSONL log in the run's resume chain, oldest first, cached the same way as log_url.
• Returns an empty list when presigning is unavailable so clients can fall back to session_logs/.
• Regenerated OpenAPI types.

The PostHog Code client prefers downloading history straight from these URLs and keeps the paginated endpoint as fallback (PostHog/code#3489), which also preserves compatibility for old clients.

How did you test this code?

Added API tests to TestTaskRunAPI: a chainless run returns exactly its own presigned log URL, a resumed run returns the chain oldest first, and presigning being unavailable yields an empty list instead of a 500. All three pass locally via hogli test. ruff and hogli ci:preflight --fix are clean. I did not test against a live deployment.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

Docs update

N/A

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Authored by Claude Code (directed by @charlesvien) while debugging why very long-running cloud task runs fail to load their history in PostHog Code. The investigation traced the failure to session_logs doing a full chain read and full JSONL parse per page. We chose presigned chain URLs over byte-cursor ranged pagination in the endpoint because the presigned log_url pattern already exists on run detail and this removes Django from the history byte path entirely. A follow-up should address the append_log full read-modify-write on the write path. Skills used: /improving-drf-endpoints and /writing-tests (read as repo skill files).

[github-actions]

🤖 CI report

⚠️ Bundle size — 🔺 +90 B (+0.0%)

Uncompressed size of every built .js bundle, compared against the base branch.

Total: 64.77 MiB · 🔺 +90 B (+0.0%)

No file changed by more than 1000 B.

_{Posted automatically by build-bundle-size-report · uncompressed bytes from dist-report}

✅ Eager graph — within budget

How much code each root ships on the eager path — downloaded and parsed before the surface is interactive. Measured from the esbuild output chunks (post-tree-shake, static imports only); lazy import() / React.lazy chunks are not counted.

Root	Eager (shipped)	Δ vs base	Budget
entry (logged-out pages, app bootstrap) src/index.tsx	1.22 MiB · 22 files	no change	███░░░░░░░ 28.4% of 4.29 MiB
authenticated shell (every logged-in page) src/scenes/AuthenticatedShell.tsx	8.13 MiB · 2,978 files	🔺 +30 B (+0.0%)	█████████░ 87.9% of 9.25 MiB

🟢 node_modules/monaco-editor/ stays out of src/index.tsx
🟢 src/lib/components/ActivityLog/describers stays out of src/index.tsx
🟢 [object Object] stays out of src/index.tsx
🟢 [object Object] stays out of src/index.tsx
🟢 node_modules/monaco-editor/ stays out of src/scenes/AuthenticatedShell.tsx
🟢 src/lib/components/ActivityLog/describers stays out of src/scenes/AuthenticatedShell.tsx
🟢 [object Object] stays out of src/scenes/AuthenticatedShell.tsx
🟢 [object Object] stays out of src/scenes/AuthenticatedShell.tsx

Largest files eagerly shipped from src/index.tsx

Size	File
126.8 KiB	../node_modules/.pnpm/react-dom@18.3.1_react@18.3.1/node_modules/react-dom/cjs/react-dom.production.min.js
24.6 KiB	../node_modules/.pnpm/buffer@6.0.3/node_modules/buffer/index.js
6.3 KiB	../node_modules/.pnpm/react@18.3.1/node_modules/react/cjs/react.production.min.js
4.5 KiB	../node_modules/.pnpm/@jspm+core@2.1.0/node_modules/@jspm/core/nodelibs/browser/process.js
3.9 KiB	../node_modules/.pnpm/scheduler@0.23.2/node_modules/scheduler/cjs/scheduler.production.min.js
1.4 KiB	../node_modules/.pnpm/base64-js@1.5.1/node_modules/base64-js/index.js
1.3 KiB	src/RootErrorBoundary.tsx
912 B	../node_modules/.pnpm/ieee754@1.2.1/node_modules/ieee754/index.js
789 B	src/scenes/ChunkLoadErrorBoundary.tsx
762 B	src/index.tsx

Largest files eagerly shipped from src/scenes/AuthenticatedShell.tsx

Size	File
281.3 KiB	../node_modules/.pnpm/posthog-js@1.402.3/node_modules/posthog-js/dist/rrweb.js
267.7 KiB	../node_modules/.pnpm/@posthog+icons@0.38.0_react-dom@18.3.1_react@18.3.1__react@18.3.1/node_modules/@posthog/icons/dist/posthog-icons.es.js
235.5 KiB	src/taxonomy/core-filter-definitions-by-group.json
222.9 KiB	../node_modules/.pnpm/posthog-js@1.402.3/node_modules/posthog-js/dist/module.js
164.0 KiB	src/queries/validators.js
154.3 KiB	../node_modules/.pnpm/re2js@0.4.1/node_modules/re2js/build/index.esm.js
126.8 KiB	../node_modules/.pnpm/react-dom@18.3.1_react@18.3.1/node_modules/react-dom/cjs/react-dom.production.min.js
105.8 KiB	src/lib/api.ts
93.3 KiB	../node_modules/.pnpm/prosemirror-view@1.40.1/node_modules/prosemirror-view/dist/index.js
92.7 KiB	../packages/quill/packages/quill/dist/index.js

_{Posted automatically by check-eager-graph · sizes are eager output bytes (shipped, post-tree-shake) from the esbuild metafile · part of #32479}

✅ Dist folder size — 🔺 +131.0 KiB (+0.0%)

Total size of the built frontend/dist folder (all assets), compared against the base branch.

Total: 1312.62 MiB · 🔺 +131.0 KiB (+0.0%)

[trunk-io]

     

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[charlesvien]

@greptileai

[greptile-apps]

_{Reviews (1): Last reviewed commit: "Merge remote-tracking branch 'origin/mas..." | Re-trigger Greptile}