Example http-client with circuit breaker support and keep alive connection with axios in Node.js

http-client.js

const axios = require("axios");
const Agent = require("agentkeepalive");
const CircuitBreaker = require("opossum");

// Replace with your configs
const TIMEOUT_DEFAULT = 2500;
const MAX_SOCKETS = 100;
const MAX_FREE_SOCKET = 10;
const TIME_OUT_KEEP_ALIVE = 60000;
const FREE_SOCKET_TIMEOUT = 30000;
const RESET_TIMEOUT_CIRCUIT_BREAKER = 15000;
const ERROR_THRESHOLD_PERCENT_CIRCUIT_BREAKER = 25;

// Replace with your logger
const logger = console;

/**
 * Create the configuration for agent http
 * @returns {object}
 */
function createHttpAgent() {
  return new Agent({
    maxSockets: MAX_SOCKETS,
    maxFreeSockets: MAX_FREE_SOCKET,
    timeout: TIME_OUT_KEEP_ALIVE,
    freeSocketTimeout: FREE_SOCKET_TIMEOUT,
  });
}

/**
 * Create the configuration for agent https
 * @returns {object}
 */
function createHttpsAgent() {
  return new Agent.HttpsAgent({
    maxSockets: MAX_SOCKETS,
    maxFreeSockets: MAX_FREE_SOCKET,
    timeout: TIME_OUT_KEEP_ALIVE,
    freeSocketTimeout: FREE_SOCKET_TIMEOUT,
  });
}

/**
 * Create an instance with axios with keep alive feature
 * @param {object} config
 * @returns {object}
 */
function createInstance(config) {
  const httpClient = axios.create(config || { timeout: TIMEOUT_DEFAULT });

  httpClient.defaults.httpAgent = createHttpAgent();
  httpClient.defaults.httpsAgent = createHttpsAgent();

  return httpClient;
}

/**
 * Create an instance for the circuit breaker for any method
 * @param {Function} handler
 * @param {object} options
 * @returns CircuitBreaker
 */
function createCircuitBreaker(handler, options) {
  const circuitBreaker = new CircuitBreaker(handler, {
    resetTimeout: RESET_TIMEOUT_CIRCUIT_BREAKER,
    errorThresholdPercentage: ERROR_THRESHOLD_PERCENT_CIRCUIT_BREAKER,
    timeout: TIMEOUT_DEFAULT,
    errorFilter: (err) => err.statusCode !== 401 || err.statusCode !== 403,
    ...options,
  });

  circuitBreaker.on("halfOpen", () => {
    logger.warn(
      `The Circuit Breaker is "HALF_OPEN" for "${circuitBreaker.name}"`
    );
  });

  circuitBreaker.on("open", () => {
    logger.error(`The Circuit Breaker is "OPEN" for "${circuitBreaker.name}"`);
  });

  circuitBreaker.on("success", (response) => {
    logger.debug(`API response: ${JSON.stringify(response, null, 2)}`);
  });

  return circuitBreaker;
}

// Example using the instance axios with the circuit breaker support
// Only for check, remove 
(async () => {
  async function getCountryArgentina() {
    const { data } = await axiosInstance.get(
      `https://restcountries.com/v3.1/name/argentina`,
      {
        params: { fields: "name, capital, flag" },
      }
    );

    return data;
  }

  const axiosInstance = createInstance();
  const circuitBreaker = createCircuitBreaker(getCountryArgentina);

  await circuitBreaker.fire();
})();

module.exports = { createInstance, createCircuitBreaker };