IDCardRenewer.js

"use strict";

const Redis = require("../../service/cache/redis");

class IDCardRenewer {
  constructor() {
    this.redis = null;
    this.refreshTimer = null;
    this.nodeIdKey = null;
    this.refreshDelay = 2000;
    this.disposed = true; // Disposed until initialized
  }

  async init(config) {
    if (!this.disposed) {
      return; // Already initialized
    }

    this.disposed = false;
    this.nodeIdKey = config.nodeIdKey;
    this.refreshDelay = config.refreshDelay || 2000;
    this.refreshMultiplier = config.refreshMultiplier;

    /**
     * Since we do not have access to the Kuzzle Context we can't use kuzzle.ask('core:cache:internal:*',...),
     * so we need to have an instance of Redis similar to the one used in the Cache Engine
     */
    try {
      const redisConf = config.redis || {};
      await this.initRedis(redisConf.config, redisConf.name);
    } catch (error) {
      // eslint-disable-next-line no-console
      console.error(
        `Failed to connect to redis, could not refresh ID card: ${error.message}`
      );
      this.parentPort.postMessage({
        error: `Failed to connect to redis, could not refresh ID card: ${error.message}`,
      });
      return;
    }

    /**
     * Early renew, otherwise we need to wait the refreshDelay before the first ID Card renewal
     * which could be enough to make the ID Card expire.
     */
    await this.renewIDCard();
    if (!this.disposed) {
      this.refreshTimer = setInterval(
        this.renewIDCard.bind(this),
        this.refreshDelay
      );
    }

    // Notify that the worker is running and updating the ID Card
    process.send({ initialized: true });
  }

  async initRedis(config, name) {
    const redis = new Redis(config, name);
    await redis.init();
    this.redis = redis;
  }

  async renewIDCard() {
    if (this.disposed) {
      return; // Do not refresh ID Card when worker has been disposed
    }

    try {
      const refreshed = await this.redis.commands.pexpire(
        this.nodeIdKey,
        this.refreshDelay * this.refreshMultiplier
      );
      // Unable to refresh the key in time before it expires
      // => this node is too slow, we need to remove it from the cluster
      if (refreshed === 0) {
        await this.dispose();
        process.send({
          error: "Node too slow: ID card expired",
        });
      }
    } catch (error) {
      await this.dispose();
      process.send({
        error: `Failed to refresh ID Card: ${error.message}`,
      });
    }
  }

  async dispose() {
    if (this.disposed) {
      return; // Already disposed
    }

    this.disposed = true;

    clearInterval(this.refreshTimer);
    this.refreshTimer = null;

    // If the worker is disposed before it had time to starts, redis service
    // may not have been initialized
    if (!this.redis) {
      return;
    }

    try {
      await this.redis.commands.del(this.nodeIdKey);
    } catch (error) {
      // eslint-disable-next-line no-console
      console.error(
        `Could not delete key '${this.nodeIdKey}' from redis: ${error.message}`
      );
    }
  }
}

const idCardRenewer = new IDCardRenewer();

process.on("message", async (message) => {
  if (message.action === "start") {
    // Simulate basic global Kuzzle Context
    global.kuzzle = { ...message.kuzzle };
    global.kuzzle.log = {
      debug: console.debug, // eslint-disable-line no-console
      error: console.error, // eslint-disable-line no-console
      info: console.info, // eslint-disable-line no-console
      warn: console.warn, // eslint-disable-line no-console
    };
    // Should never throw
    await idCardRenewer.init(message);
  } else if (message.action === "dispose") {
    // Should never throw
    await idCardRenewer.dispose();
    process.exit(0);
  }
});

module.exports = { IDCardRenewer };