dome-throttle

Token-bucket rate limiting and budget tracking for MCPDome.

What it does

• Provides RateLimiter with global, per-identity, and per-tool token-bucket rate limiting, using DashMap for lock-free concurrent access.
• TOCTOU-safe bucket access — uses DashMap's entry() API for atomic get-or-insert, eliminating race conditions in concurrent bucket creation.
• LRU eviction with TTL — DashMap entries are automatically cleaned up when the map exceeds max_entries, preventing unbounded memory growth from unique identity/tool combinations.
• Provides BudgetTracker for cumulative spend tracking per identity with configurable rolling time windows, caps, and TTL-based eviction.
• Returns DomeError::RateLimited or DomeError::BudgetExhausted on violation, allowing the interceptor chain to block and audit the request.
• Supports configurable bucket sizes, refill rates, global limits, and budget limits via RateLimiterConfig and BudgetTrackerConfig.

Usage

[dependencies]
dome-throttle = "0.4"

use dome_throttle::{RateLimiter, RateLimiterConfig};

let limiter = RateLimiter::new(RateLimiterConfig::default());
limiter.check_rate_limit("user:alice", Some("read_file"))?;

Part of MCPDome

This crate is part of MCPDome, a security gateway for the Model Context Protocol. See the main repository for full documentation.

License

Apache-2.0