Rate limiting (token bucket)

[ralyodio]

📋 Product Requirements Document

PRD: Rate limiting (token bucket)

Issue: #157
Milestone: Phase 5: Webhook System
Labels: webhook-triggers, hacktoberfest

---

PRD: Implementing Rate Limiting Using Token Bucket Algorithm for MeshHook

Overview

The objective of this task is to integrate a rate limiting mechanism, specifically using the token bucket algorithm, into the MeshHook project’s webhook system. This enhancement is pivotal for controlling resource consumption, ensuring equitable resource distribution among tenants, and safeguarding the system against potential abuse. It aligns with MeshHook’s overarching goals of scalability, security, and robust workflow management, thereby supporting its mission to offer a webhook-first, deterministic, Postgres-native workflow engine that is both efficient and secure.

Functional Requirements

1. Token Bucket Algorithm Integration: Implement the token bucket algorithm to enforce rate limiting on webhook triggers.
2. Tenant/Project-Based Configuration: Allow rate limits to be configurable at the tenant or project level, ensuring flexibility and customization.
3. Rate Limit Status Headers: Append HTTP headers (X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset) to responses to provide clients with rate limit status information.
4. Handling Over Limit Requests: Implement logic to handle requests exceeding the rate limit, including issuing a 429 Too Many Requests response and logging the attempt.
5. Rate Limit Management API: Provide an API endpoint for administrators to configure rate limits per tenant or project.

Non-Functional Requirements

• Performance: The rate limiting feature must maintain a high-performance benchmark, adding no more than 10ms of overhead to any webhook request processing.
• Scalability: Design the rate limiting solution to easily scale with the growth in webhook traffic and the number of tenants.
• Reliability: Ensure the rate limiting operates reliably, accurately tracking and enforcing limits without erroneous blocking or allowance.
• Security: Utilize MeshHook’s existing role-level security (RLS) framework to secure access to rate limit configurations.

Technical Specifications

Architecture Context

MeshHook is built on a modern stack that includes SvelteKit for frontend interactions and Supabase (encompassing Postgres, Realtime, and more) for backend functionalities. The rate limiting feature will be integrated into the webhook processing flow, managed by SvelteKit services, with configurations stored and managed in the Postgres database.

Implementation Approach

1. Integration Point Analysis: Review the webhook processing pipeline to identify where rate limiting checks should be applied.
2. Design:
   • Data Model Extension: Update the tenant_settings table in Postgres to include rate_limit_rps (rate limit requests per second).
   • Algorithm Implementation: Select an efficient token bucket algorithm suitable for concurrent access and minimal performance impact.
   • API Development: Create an endpoint /api/v1/tenants/{tenantId}/rate_limit for updating tenant-specific rate limit settings.
3. Implementation: Develop the rate limiting feature, emphasizing efficiency and minimal impact on existing functionalities.
4. Testing: Execute thorough testing, covering various scenarios including limit overreaches and dynamic limit adjustments.
5. Documentation: Update both API and developer documentation to reflect the new rate limiting feature, including configuration and operation guidelines.

Data Model Changes

• Modify tenant_settings:
  • Add rate_limit_rps (INTEGER): Defines the maximum number of requests per second (RPS) each tenant is allowed.

API Endpoints

• Update Tenant Rate Limit:
  • Method: POST
  • Endpoint: /api/v1/tenants/{tenantId}/rate_limit
  • Payload: { "rate_limit_rps": number }
  • Response: 200 OK, { "message": "Rate limit updated successfully." }

Acceptance Criteria

• Token bucket rate limiting is implemented for all webhook triggers.
• Tenants can customize their rate limits through a dedicated API endpoint.
• Responses for exceeded limits correctly include rate limiting headers and a 429 status code.
• Integration and unit tests validate functionality against performance benchmarks.
• Documentation provides clear guidance on configuring and understanding rate limits.

Dependencies

• Access to the project's existing database schema for necessary modifications.
• Integration with MeshHook’s authentication and authorization mechanisms for secure API access.

Implementation Notes

Development Guidelines

• Adhere to MeshHook’s coding standards and architectural patterns.
• Ensure the rate limiting module is flexible for future enhancements or algorithm adjustments.

Testing Strategy

• Unit Testing: Focus on algorithm precision under various load conditions.
• Integration Testing: Validate the seamless operation of rate limiting within the webhook processing workflow, including dynamic configuration changes.

Security Considerations

• Confirm that rate limit setting changes are securely authenticated and authorized.
• Guard against potential denial-of-service strategies aimed at exploiting rate limiting logic.

Monitoring and Observability

• Implement logging for events when requests are rate-limited and for changes to rate limit configurations.
• Monitor the impact of rate limiting on overall webhook processing performance.

By adhering to these specifications, MeshHook will introduce a robust rate limiting feature that enhances its security, efficiency, and scalability, further solidifying its position as a leading workflow engine solution.

---

This PRD was AI-generated using gpt-4-turbo-preview from GitHub issue #157
Generated: 2025-10-10

📎 Generated Documentation

• 📄 PRD Document: 157-rate-limiting-token-bucket.md
• 🎨 PlantUML Diagram: 157-rate-limiting-token-bucket.puml
• 🖼️ Diagram Image: 157-rate-limiting-token-bucket.png

---

This issue body was auto-generated from the PRD. Original issue content is preserved in the PRD document.
Last updated: 2025-10-10

[pranjalarora98]

@ralyodio I would like to work on this issue