Resilience

Resilience is built on [Cockatiel](https://github.com/connor4312/cockatiel) with redis.

Table of Contents

1. About The Project
   • Built With
2. Getting Started
   • Prerequisites
   • Installation
3. Usage
4. Contributing

About The Project

An enhancement to a circuit breaker with a rate limiter to protect your application from overloading due to excessive requests. The breaker can be used to stop sending requests to a service that is failing or is overloaded together with the rate limiter that limits the number of requests that can be made within a certain time period. Together, circuit breaker and rate limiter can help prevent your application from crashing or becoming unresponsive due to too many requests.

(back to top)

Built With

This project is built on the top of cockatiel.

• Cockatiel

(back to top)

Getting Started

You should have a basic setup of nodejs project using typescript

Prerequisites

Should have a sound knowledge of Circuit Breaker, Rate Limiter and typescript. Redis should be installed on your machine

Installation

1. Install redis sampling breaker package

   npm i @carbonteq/resilience

(back to top)

Usage

Then go forth with sampling breaker:

import {
  ExponentialBackoff,
  retry,
  handleAll,
  circuitBreaker,
  wrap,
  RedisSamplingBreaker
} from '@carbonteq/resilience';
import axios from "axios";
import Redis from "ioredis";

// Create a retry policy that'll try whatever function we execute 3
// times with a randomized exponential backoff.
const retry = retry(handleAll, { maxAttempts: 3, backoff: new ExponentialBackoff() });

// Create a circuit breaker that'll stop calling the executed function for 10
// seconds if it fails 5 times in a row. This can give time for e.g. a database
// to recover without getting tons of traffic.
const circuitBreakerPolicy = circuitBreaker(handleAll, {
  halfOpenAfter: 10 * 1000,
  breaker: new RedisSamplingBreaker({ threshold: 0.2, duration: 30 * 1000, redisClient: new Redis() }),
});

// Combine these! Create a policy that retries 3 times, calling through the circuit breaker
const retryWithBreaker = wrap(retry, circuitBreakerPolicy);

exports.handleRequest = async (req, res) => {
  const data = await retryWithBreaker.execute(() => axios.get("http://127.0.0.1:8080"));
  return res.json(data);
};

With rate limiting policy and sliding window counter driver:

import * as crypto from "crypto"
import axios from "axios";
import Redis from "ioredis";
import {handleAll, rateLimiter,SlidingWindowCounterDriver } from "@carbonteq/resilience";

exports.handleRequest = async (req, res) => {
  const hash = crypto.createHash("md5").update(req.ip).digest("hex");
  const rateLimiterPolicy = rateLimiter(handleAll, {
    redisClient: new Redis(),
    driver: new SlidingWindowCounterDriver({
      hash: hash,
      maxWindowRequestCount: 5,
      intervalInSeconds: 1 * 60,
    }),
  });

  const data = await rateLimiterPolicy.execute(() => axios.get("http://127.0.0.1:8080"));
  return res.json(data);
};

With rate limiting policy and leaky bucket driver:

import * as crypto from "crypto"
import axios from "axios";
import Redis from "ioredis";
import { handleAll, rateLimiter,LeakyBucketDriver } from "@carbonteq/resilience";

exports.handleRequest = async (req, res) => {
  const hash = crypto.createHash("md5").update(req.ip).digest("hex");
  const rateLimiterPolicy = rateLimiter(handleAll, {
    redisClient: new Redis(),
    driver: new LeakyBucketDriver({
      hash: hash,
      bucketSize: 5,
      fillRate: 10,
    }),
  });

  const data = await rateLimiterPolicy.execute(() => axios.get("http://127.0.0.1:8080"));
  return res.json(data);
};

Wrap both rate limiting and sampling breaker:

import * as crypto from "crypto"
import {
  handleAll,
  retry,
  circuitBreaker,
  rateLimiter,
  RedisSamplingBreaker,
  SlidingWindowCounterDriver
} from '@carbonteq/resilience';
import axios from "axios";
import Redis from "ioredis";

const circuitBreakerPolicy = circuitBreaker(handleAll, {
  halfOpenAfter: 10 * 1000,
  breaker: new SamplingBreaker({ threshold: 0.2, duration: 30 * 1000,redisClient: new Redis() }),
});

const retryPolicy = retry(handleAll, {
  maxAttempts: 3,
  backoff: new ExponentialBackoff(),
});
exports.handleRequest = async (req, res) => {
    const hash = crypto.createHash("md5").update(req.ip).digest("hex");
    const rateLimiterPolicy = rateLimiter(handleAll, {
      redisClient: new Redis(),
      driver: new SlidingWindowCounterDriver({
        hash: hash,
        maxWindowRequestCount: 5,
        intervalInSeconds: 1 * 60,
      }),
    });

  
  const retryWithBreaker = wrap(redisRateLimiterPolicy,retryPolicy,circuitBreakerPolicy);
  const data = await retryWithBreaker.execute(() => axios.get("http://127.0.0.1:8080"));
  return res.json(data);
};

(back to top)

Contributing

Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.

If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement". Don't forget to give the project a star! Thanks again!

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

(back to top)