BullMQ

npm install healthzkit @healthzkit/bullmq bullmq@^5

import { Queue } from "bullmq";
import { createHealthKit, toFetchResponse } from "healthzkit";
import { bullmqAdapter } from "@healthzkit/bullmq/bullmq";

// Your application's Queue, also used by its producers.
const queue = new Queue("emails", {
  connection: {
    host: "127.0.0.1",
    port: 6379,
    connectTimeout: 1_000,
    commandTimeout: 1_000,
    maxRetriesPerRequest: 1,
    retryStrategy: () => null,
    enableOfflineQueue: false,
  },
});
queue.on("error", (error) => console.error("Queue connection error", error));

const kit = createHealthKit({
  checks: [
    {
      name: "email-queue",
      type: ["readiness"],
      adapter: bullmqAdapter({
        queue,
        thresholds: { waiting: 1_000, paused: 0 },
      }),
      timeout: 2_000,
      schedule: { intervalMs: 30_000 },
      onDegraded: { httpStatus: 503 },
    },
  ],
  output: { exposeError: false, exposeMetadata: false },
});
kit.start();

// Wire this into your framework's readiness route.
export async function readiness() {
  return toFetchResponse(await kit.handleReadiness());
}

// Invoke after your server stops accepting traffic and producers have drained.
export async function shutdown() {
  const deadline = setTimeout(() => process.exit(1), 5_000);
  deadline.unref();
  kit.beginDrain();
  try {
    await kit.close();
    await queue.close(); // Application-owned resources close after health checks.
  } finally {
    clearTimeout(deadline);
  }
}