0xTim / vapor-clientratelimiter

Vapor Client Rate Limiter

Library for throttling requests to third party APIs to ensure you don't exceed a rate limit. Designed to be used when your application scales across multiple instances. Requires Postgres as it uses database locks to queue requests across instances.

Usage

Setup in configure.swift

let clientRateLimiterConfig = RateLimiterConfig(maxRequestsPerSecond: 5, timeout: 60)
app.clientRateLimiters.use {
    ClientRateLimiter(byteBufferAllocator: $0.allocator, logger: $0.logger, client: $0.client, db: $0.db, config: clientRateLimiterConfig)
}

Add the migrations for storing the data:

app.migrations.add(CreateHostRequestTime())
app.migrations.add(CreateRateLimitedRequest())

You can configure the maximum number of requests per second to send and a timeout for requests if you're under heavy load. Then, route requests through the clientRateLimiter:

let response = try await req.clientRateLimiter.get("https://www.google.com")

Custom Rate Limits Per Site

There is initial support for allowing different sites to have differnt rate limits. You can configure this when setting up the config like so:

let clientRateLimiterConfig = RateLimiterConfig(defaultMaxRequestsPerSecond: 5, timeout: 60, siteSpecificRPS: [
    "api.google.com": 100,
    "api.mysite.com": 10
])