index.js

const { ApolloServer, PubSub } = require("apollo-server-express");

const { withFilter } = require("graphql-subscriptions");

const express = require("express");
const schema = require("./schema");
const { createServer } = require("http");

const { DUMMY_DATA, PORT } = require("./constants");
const units = require("./units");

const pubsub = new PubSub();
const app = express();
const httpServer = createServer(app);

const resolvers = {
  Query: {
    units: () => DUMMY_DATA
  },
  Subscription: {
    unitAdded: {
      subscribe: (_, variables, connection) => {
        setTimeout(() => {
          publishTestData({ url: variables.url });
        }, 1000);

        return withFilter(
          () => pubsub.asyncIterator("unitAdded"),
          (payload, variables) => {
            return payload.unitAdded.url === variables.url;
          }
        )(_, variables, connection);
      }
    }
  }
};
const server = new ApolloServer({
  typeDefs: schema,
  resolvers
});

server.applyMiddleware({ app, path: "/graphql" });
server.installSubscriptionHandlers(httpServer);

httpServer.listen(PORT, () => {
  console.log(
    `🚀 Server ready at http://localhost:${PORT}${server.graphqlPath}`
  );
  console.log(
    `🚀 Subscriptions ready at ws://localhost:${PORT}${
      server.subscriptionsPath
    }`
  );
});

/*
  TODO
  [] Optimize memory usage
*/

const generateRandomType = () =>
  Math.random() > 0.66 ? "info" : Math.random() > 0.33 ? "warning" : "okay";

const publishTestData = ({ url }) => {
  /*
  `url` contains all input from a form
    Example value:
      http://123.2.2.2/51582/EBS#Elbrus    
  */
  let countOfUnitsPassed = 0;
  const countOfUnitsAll = units.length;
  const SUBSCRIPTION_NAME = "unitAdded";

  units.forEach(async unit => {
    const { title, run } = unit;
    let payload = {};

    try {
      const responseFromUnit = await run({ url });
      countOfUnitsPassed++;
      payload[SUBSCRIPTION_NAME] = {
        id: Date.now(),
        url,
        status: countOfUnitsPassed === countOfUnitsAll ? "resolved" : "pending",
        type: responseFromUnit.error ? "error" : generateRandomType(),
        title,
        description: responseFromUnit.result,
        details: responseFromUnit.details
      };
    } catch (e) {
      countOfUnitsPassed++;
      payload[SUBSCRIPTION_NAME] = {
        id: Date.now(),
        url,
        status: countOfUnitsPassed === countOfUnitsAll ? "resolved" : "pending",
        type: "error",
        title,
        description: "ERROR"
      };
    }
    pubsub.publish(SUBSCRIPTION_NAME, payload);
  });
};