fix(terminal): reconnect to running executions after page refresh by waleedlatif1 · Pull Request #3200 · simstudioai/sim

waleedlatif1 · 2026-02-11T21:47:38Z

Summary

Add Redis event buffer that dual-writes execution events alongside SSE for reconnection
Add SSE reconnection endpoint (GET /api/workflows/[id]/executions/[executionId]/stream)
Client detects running entries after page refresh and reconnects to replay events from Redis
Server remains sole authority for execution IDs — client receives via X-Execution-Id header
Defers clearing old console entries until first reconnection event arrives (no visual jitter)
Graceful degradation: works without Redis (reconnection returns 404, entries marked stale)

Type of Change

Bug fix

Testing

Tested manually

Checklist

Code follows project style guidelines
Self-reviewed my changes
Tests added/updated and passing
No new warnings introduced
I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

vercel · 2026-02-11T21:47:43Z

The latest updates on your projects. Learn more about Vercel for GitHub.

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Feb 12, 2026 2:59am

greptile-apps · 2026-02-11T21:50:30Z

Greptile Overview

Greptile Summary

Adds Redis-backed event buffering and SSE reconnection to restore running executions after page refresh. The implementation dual-writes execution events to Redis alongside SSE streaming, allowing clients to detect running console entries on mount and reconnect to replay missed events.

Key changes:

New event-buffer.ts with Redis sorted sets for event storage (1-hour TTL, 1000 event limit per execution)
New reconnection endpoint GET /api/workflows/[id]/executions/[executionId]/stream with polling for terminal status
Client-side reconnection logic in use-workflow-execution.ts detects running entries after hydration, cancels zombies, and replays events
Defers clearing old console entries until first reconnection event arrives to prevent visual jitter
Graceful degradation: works without Redis (reconnection returns 404, entries marked as unavailable)

Issues addressed:

Previous review flagged zadd bug and invalid from handling — both are now fixed
Server remains sole authority for execution IDs via X-Execution-Id header

Minor style concerns:

Reconnection cleanup logic uses dual flags (cleanupRan and reconnectionComplete) that could be simplified
cancelRunningEntries timing relative to reconnection setup could be clearer

Confidence Score: 4/5

Safe to merge with minor style improvements recommended
Critical bugs from previous review (zadd and from validation) are fixed. Core reconnection logic is sound with proper auth checks, graceful degradation, and duplicate execution handling. Two style comments suggest minor cleanup opportunities but don't affect correctness.
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts — reconnection cleanup logic could be simplified (see comments on lines 2098 and 2245)

Important Files Changed

Filename	Overview
apps/sim/lib/execution/event-buffer.ts	new Redis-backed event buffer with proper zadd implementation, validates ID reservation logic correctly
apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts	new SSE reconnection endpoint with proper `from` parameter validation and auth checks, polls for new events until terminal status
apps/sim/app/api/workflows/[id]/execute/route.ts	integrates event writer to dual-write execution events to Redis alongside SSE streaming, returns `X-Execution-Id` header
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts	adds reconnection logic in useEffect to detect running entries after page refresh, has minor style issues with state management but core logic is sound
apps/sim/hooks/use-execution-stream.ts	adds `reconnect` method to hook for connecting to the stream endpoint with `fromEventId` query parameter

Sequence Diagram

sequenceDiagram
    participant User
    participant Browser
    participant ExecuteAPI as /api/workflows/[id]/execute
    participant EventBuffer as Redis Event Buffer
    participant StreamAPI as /api/workflows/[id]/executions/[executionId]/stream
    participant Console as Terminal Console Store

    Note over User,Console: Initial Execution
    User->>Browser: Start workflow execution
    Browser->>ExecuteAPI: POST with workflow input
    ExecuteAPI->>EventBuffer: createExecutionEventWriter(executionId)
    ExecuteAPI->>EventBuffer: setExecutionMeta(status: active)
    ExecuteAPI-->>Browser: SSE stream + X-Execution-Id header
    
    loop Execution Events
        ExecuteAPI->>EventBuffer: writer.write(event)
        ExecuteAPI->>Browser: SSE event
        Browser->>Console: addConsole(entry with isRunning: true)
    end
    
    ExecuteAPI->>EventBuffer: setExecutionMeta(status: complete)
    ExecuteAPI->>EventBuffer: writer.close()
    ExecuteAPI->>Browser: [DONE]
    Browser->>Console: Update entries (isRunning: false)

    Note over User,Console: Page Refresh / Navigation
    User->>Browser: Refresh page
    Browser->>Browser: Zustand rehydrates from IndexedDB
    Browser->>Console: Load persisted entries
    
    alt Running entries found
        Browser->>Browser: Detect isRunning entries in console
        Browser->>Console: Sort by startedAt, pick most recent
        Browser->>Console: cancelRunningEntries (mark old zombies as cancelled)
        Browser->>StreamAPI: GET /stream?from=0
        StreamAPI->>StreamAPI: authorizeWorkflowByWorkspacePermission
        StreamAPI->>EventBuffer: getExecutionMeta(executionId)
        
        alt Buffer exists
            StreamAPI->>EventBuffer: readExecutionEvents(executionId, fromEventId)
            EventBuffer-->>StreamAPI: Buffered events
            StreamAPI-->>Browser: SSE replay of events
            Browser->>Console: clearOnce() - clear old entries
            Browser->>Console: Add/update entries from replayed events
            
            loop Poll for new events (until terminal status)
                StreamAPI->>EventBuffer: readExecutionEvents(lastEventId)
                StreamAPI->>EventBuffer: getExecutionMeta()
                alt New events available
                    StreamAPI-->>Browser: SSE new events
                    Browser->>Console: Update console entries
                end
            end
            
            StreamAPI->>Browser: [DONE]
            Browser->>Console: Mark execution complete
        else Buffer expired (404)
            StreamAPI-->>Browser: 404 error
            Browser->>Console: Mark entries with warning (unavailable)
        end
    end

greptile-apps

_{9 files reviewed, 3 comments}

_{Edit Code Review Agent Settings | Greptile}

apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts

apps/sim/lib/execution/event-buffer.ts

greptile-apps · 2026-02-11T21:50:41Z

Additional Comments (1)

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts
comparing execution IDs from different runs could fail if sorted entries span multiple executions - entries from old executions may remain with isRunning=true

… stream

…rd<string, unknown> Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

waleedlatif1 · 2026-02-11T21:58:39Z

@greptile
@cursor review

greptile-apps

_{9 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

apps/sim/lib/execution/event-buffer.ts

apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts

…oint Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

waleedlatif1 · 2026-02-11T22:35:00Z

@cursor review
@greptile

greptile-apps

_{9 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts

greptile-apps · 2026-02-11T22:38:41Z

Additional Comments (1)

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts
Cancel endpoint /api/workflows/${activeWorkflowId}/executions/${storedExecutionId}/cancel doesn't exist in this PR, will return 404

…ock (#3199)

…prop (#3201)

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…ock re-entry Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…ted by navigation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

waleedlatif1 · 2026-02-12T01:59:29Z

@greptile
@cursor review

greptile-apps

_{9 files reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

apps/sim/lib/execution/event-buffer.ts

waleedlatif1 · 2026-02-12T02:11:39Z

@cursor review

waleedlatif1 · 2026-02-12T02:16:06Z

@cursor review

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts

apps/sim/lib/execution/event-buffer.ts

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts

apps/sim/hooks/use-execution-stream.ts

waleedlatif1 · 2026-02-12T03:00:05Z

@cursor review

waleedlatif1 · 2026-02-12T03:00:08Z

@greptile

greptile-apps

_{12 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts

cursor

Cursor Bugbot has reviewed your changes and found 2 potential issues.

^{Bugbot Autofix is OFF. To automatically fix reported issues with Cloud Agents, enable Autofix in the Cursor dashboard.}

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts

) * fix(terminal): reconnect to running executions after page refresh * fix(terminal): use ExecutionEvent type instead of any in reconnection stream * fix(execution): type event buffer with ExecutionEvent instead of Record<string, unknown> Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * fix(execution): validate fromEventId query param in reconnection endpoint Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * Fix some bugs * fix(variables): fix tag dropdown and cursor alignment in variables block (#3199) * feat(confluence): added list space labels, delete label, delete page prop (#3201) * updated route * ack comments * fix(execution): reset execution state in reconnection cleanup to unblock re-entry Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * fix(execution): restore running entries when reconnection is interrupted by navigation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * done * remove cast in ioredis types * ack PR comments --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> Co-authored-by: Siddharth Ganesan <siddharthganesan@gmail.com>

fix(terminal): reconnect to running executions after page refresh

db19975

greptile-apps bot reviewed Feb 11, 2026

View reviewed changes

apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts Outdated Show resolved Hide resolved

apps/sim/lib/execution/event-buffer.ts Show resolved Hide resolved

fix(terminal): use ExecutionEvent type instead of any in reconnection…

fde8f97

… stream

vercel bot temporarily deployed to Preview February 11, 2026 21:52 Inactive

fix(execution): type event buffer with ExecutionEvent instead of Reco…

a5e8a30

…rd<string, unknown> Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vercel bot temporarily deployed to Preview February 11, 2026 21:57 Inactive

greptile-apps bot reviewed Feb 11, 2026

View reviewed changes

apps/sim/lib/execution/event-buffer.ts Show resolved Hide resolved

apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts Show resolved Hide resolved

fix(execution): validate fromEventId query param in reconnection endp…

ef477ba

…oint Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vercel bot temporarily deployed to Preview February 11, 2026 22:29 Inactive

greptile-apps bot reviewed Feb 11, 2026

View reviewed changes

apps/sim/app/api/workflows/[id]/executions/[executionId]/stream/route.ts Show resolved Hide resolved

Sg312 and others added 4 commits February 11, 2026 14:45

Fix some bugs

986cef3

fix(variables): fix tag dropdown and cursor alignment in variables bl…

5f3e76d

…ock (#3199)

feat(confluence): added list space labels, delete label, delete page …

7c4b925

…prop (#3201)

updated route

51bc5b5

cursor bot reviewed Feb 11, 2026

View reviewed changes

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Show resolved Hide resolved

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Show resolved Hide resolved

vercel bot deployed to Preview February 11, 2026 22:48 View deployment

Merge branch 'staging' into fix/refresh-resume

e1af0f4

vercel bot temporarily deployed to Preview February 11, 2026 22:49 Inactive

ack comments

3bb271d

vercel bot temporarily deployed to Preview February 11, 2026 22:51 Inactive

chore: merge staging and remove unrelated copilot/tmp changes

0c7a0bd

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vercel bot deployed to Preview February 11, 2026 23:42 View deployment

fix(execution): reset execution state in reconnection cleanup to unbl…

61a6b18

…ock re-entry Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vercel bot temporarily deployed to Preview February 11, 2026 23:44 Inactive

fix(execution): restore running entries when reconnection is interrup…

7af4025

…ted by navigation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vercel bot temporarily deployed to Preview February 11, 2026 23:56 Inactive

done

5b8dba0

vercel bot temporarily deployed to Preview February 12, 2026 01:59 Inactive

greptile-apps bot reviewed Feb 12, 2026

View reviewed changes

apps/sim/lib/execution/event-buffer.ts Outdated Show resolved Hide resolved

remove cast in ioredis types

19ccefa

vercel bot temporarily deployed to Preview February 12, 2026 02:15 Inactive

cursor bot reviewed Feb 12, 2026

View reviewed changes

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Outdated Show resolved Hide resolved

apps/sim/lib/execution/event-buffer.ts Show resolved Hide resolved

cursor bot reviewed Feb 12, 2026

View reviewed changes

ack PR comments

0634d05

vercel bot temporarily deployed to Preview February 12, 2026 02:59 Inactive

greptile-apps bot reviewed Feb 12, 2026

View reviewed changes

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Show resolved Hide resolved

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Show resolved Hide resolved

cursor bot reviewed Feb 12, 2026

View reviewed changes

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Show resolved Hide resolved

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-workflow-execution.ts Show resolved Hide resolved

waleedlatif1 merged commit 81dfeb0 into staging Feb 12, 2026
12 checks passed

waleedlatif1 deleted the fix/refresh-resume branch February 12, 2026 03:31

waleedlatif1 mentioned this pull request Feb 13, 2026

v0.5.89: resume execution on refresh, google books, tool input subblock improvements #3213

Merged

Conversation

waleedlatif1 commented Feb 11, 2026

Summary

Type of Change

Testing

Checklist

Uh oh!

vercel bot commented Feb 11, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

greptile-apps bot commented Feb 11, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Greptile Overview

Greptile Summary

Confidence Score: 4/5

Important Files Changed

Sequence Diagram

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

greptile-apps bot commented Feb 11, 2026

Uh oh!

waleedlatif1 commented Feb 11, 2026

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

waleedlatif1 commented Feb 11, 2026

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

greptile-apps bot commented Feb 11, 2026

Uh oh!

Uh oh!

Uh oh!

waleedlatif1 commented Feb 12, 2026

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

waleedlatif1 commented Feb 12, 2026

Uh oh!

waleedlatif1 commented Feb 12, 2026

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

waleedlatif1 commented Feb 12, 2026

Uh oh!

waleedlatif1 commented Feb 12, 2026

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

cursor bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

vercel bot commented Feb 11, 2026 •

edited

Loading

greptile-apps bot commented Feb 11, 2026 •

edited

Loading