How to check if graphql yoga server is running locally?

Question

I have a pubsub service running with Redis and I need to check if GraphQL Yoga server is up and running locally before I start it.

What's the best way to do it in Node.js with TypeScript?

healthCheckEndpoint is set to 'live', port 4000

Answer 1

In order to ensure Redis doesn't connect until GraphQL is running, you can import the redis library asynchronously inside the server's success callback.

index.js

import { createServer } from "node:http";
import { createYoga } from "graphql-yoga";
import { schema } from "./schema.js";
import redis from "./redis.js";

// Create a Yoga instance with a GraphQL schema.
const yoga = createYoga({ schema });

// Pass it into a server to hook into request handlers.
const server = createServer(yoga);

// Start the server and you're done!
server.listen(4000, async () => {
  console.info("GraphQL server is running on http://localhost:4000/graphql");

  await redis();

  return Promise.resolve();
});

redis.js

import Redis from "ioredis";

export default async () => {
  const redis = new Redis();
  return redis.set("mykey", "value");
};