feat(redis): added redis option for rate limiter, 10x speed improvement in rate limit checks & reduction of DB load

[waleedlatif1]

Summary

• added redis option for rate limiter, 10x speed improvement in rate limit checks & reduction of DB load
• falls back to DB for self-hosters who don't use redis, no disruption

Type of Change

• New feature

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)

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1 Skipped Deployment

Project	Deployment	Preview	Comments	Updated (UTC)
docs	Skipped			Dec 9, 2025 4:31am

[greptile-apps]

Greptile Overview

Greptile Summary

Implemented Redis-based rate limiting with atomic Lua script operations, achieving 10x performance improvement over the DB-only approach. The implementation includes graceful fallback to database when Redis is unavailable, ensuring no disruption for self-hosters.

Key improvements:

• Redis rate limiting uses atomic INCR + EXPIRE in a single Lua script to prevent race conditions
• Database fallback maintains existing functionality for environments without Redis
• Rate limiter module relocated from services/queue to lib/core/rate-limiter for better organization
• Comprehensive test coverage for both Redis and DB paths, including failure scenarios
• Manual executions continue to bypass rate limiting as before

Architecture:

• Fixed-window rate limiting algorithm with per-minute windows
• Separate counters for sync/async API executions and API endpoint requests
• Organization-level rate limit pooling for team/enterprise subscriptions
• Automatic fallback on Redis errors with warning logs

Confidence Score: 4/5

• Safe to merge with minor considerations about Redis connection handling in production
• The implementation properly addresses previous race condition issues with atomic Lua operations, includes comprehensive fallback logic, and has good test coverage. Score is 4 (not 5) due to lack of Redis integration tests and potential edge cases around Redis connection lifecycle in serverless environments
• apps/sim/lib/core/rate-limiter/rate-limiter.ts - verify Redis connection behavior under load

Important Files Changed

File Analysis

Filename	Score	Overview
apps/sim/lib/core/rate-limiter/rate-limiter.ts	4/5	New Redis-based rate limiter with atomic Lua script operations and DB fallback; previous race conditions addressed
apps/sim/lib/core/rate-limiter/rate-limiter.test.ts	5/5	Comprehensive test coverage for Redis and DB fallback paths, Redis failure scenarios, and different trigger types
apps/sim/app/api/v1/middleware.ts	5/5	Import path updated to new rate limiter location
apps/sim/lib/execution/preprocessing.ts	5/5	Import path updated to new rate limiter location

Sequence Diagram

sequenceDiagram
    participant Client
    participant API as API Route/Middleware
    participant RL as RateLimiter
    participant Redis as Redis Client
    participant DB as Database
    
    Client->>API: API Request
    API->>RL: checkRateLimitWithSubscription()
    
    alt Manual Trigger
        RL->>API: allowed=true (bypass)
    else API/Webhook/Schedule Trigger
        RL->>Redis: getRedisClient()
        
        alt Redis Available
            Redis-->>RL: Redis instance
            RL->>Redis: eval(Lua: INCR + EXPIRE)
            Redis-->>RL: count
            
            alt count <= limit
                RL->>API: allowed=true, remaining
            else count > limit
                RL->>API: allowed=false, remaining=0
            end
            
        else Redis Unavailable/Error
            Redis-->>RL: null or error
            RL->>DB: SELECT rate limit record
            
            alt Record Expired/Missing
                RL->>DB: INSERT with onConflictDoUpdate
                DB-->>RL: new count
            else Record Valid
                RL->>DB: UPDATE (atomic increment)
                DB-->>RL: updated count
            end
            
            alt count <= limit
                RL->>API: allowed=true, remaining
            else count > limit
                RL->>DB: UPDATE isRateLimited=true
                RL->>API: allowed=false, remaining=0
            end
        end
    end
    
    API->>Client: Response

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[greptile-apps]

_{10 files reviewed, 1 comment}

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[waleedlatif1]

@greptile

[greptile-apps]

_{10 files reviewed, 1 comment}

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[waleedlatif1]

@greptile

[waleedlatif1]

@greptile

[greptile-apps]

_{12 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}