MongoDB connection error after 1084 inserts from NodeJS

Question

I am new to MongoDB and NodeJS. I wrote a simple app that tests the write speed of a RESTFUL state API:

const express = require('express')
const port = process.env.PORT
var MongoClient = require('mongodb').MongoClient;
const router = express.Router()

router.post('/mongo-log', async(req, res) => {
    try {
      let syserr = false;
      let e = null;
      await MongoClient.connect(process.env.MONGODB_URL,async function(err,db) {
        if(err)
        {
            console.log("-------------CONNECT ERROR----------");
            console.log(err);
            process.exit(1);
        }
        const dbo = db.db(process.env.MONGODB_NAME);
        await dbo.collection("mongolog").insertOne({details:req.body.details,createDate:(new Date())},function(err,res) {

          if(err)
          {
            console.log("-------------INSERT ERROR----------");
            console.log(err);
            process.exit(1);
          }

        });
      });
      if(e) throw e;
      res.status(201).send({"success":true})
    } catch (error) {
        console.log(error);
        res.status(400).send(error)
    }

  })

var cors = require('cors')

const app = express()

app.use(cors())
app.use(express.json())
app.use(router)

if(process.env.SSL_KEY && process.env.SSL_CRT) {
    const https = require('https')
    const fs = require('fs')
    const options = {
      key: fs.readFileSync(process.env.SSL_KEY),
      cert: fs.readFileSync(process.env.SSL_CRT)
    }

    var server = https.createServer(options, app)

    server.listen(port, () => {
      console.log("server starting on port : " + port)
    })
} else {
    app.listen(port, () => {
        console.log(`Server running on port ${port}`)
    })
}

I start the app with npm start from terminal. Then I wrote a separate python script with an infinite while loop without any sleeper/timeouts that just submits {details:{a bunch of nested objects}} with a request.post().

Everything works fine for a few seconds. But the moment my API has written exactly 1084 records to mongodb, I get the following error from one of my if statements above:

-------------CONNECT ERROR----------

MongoNetworkError: failed to connect to server [127.0.0.1:27017] on first connect [Error: write EPIPE at afterWriteDispatched (internal/stream_base_commons.js:150:25) at writeGeneric (internal/stream_base_commons.js:141:3) at Socket._writeGeneric (net.js:776:11) at Socket._write (net.js:788:8) at doWrite (_stream_writable.js:453:12) at writeOrBuffer (_stream_writable.js:435:5) at Socket.Writable.write (_stream_writable.js:315:11) at Connection.write (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connection.js:271:21) at runCommand (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connect.js:384:8) at performInitialHandshake (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connect.js:122:3) { name: 'MongoNetworkError', [Symbol(mongoErrorContextSymbol)]: {} }] at Pool. (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/topologies/server.js:438:11) at Pool.emit (events.js:210:5) at /home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/pool.js:561:14 at /home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/pool.js:994:11 at callback (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connect.js:97:5) at /home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connect.js:124:7 at _callback (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connect.js:349:5) at Connection.errorHandler (/home/john/projects/dbperformance/node_modules/mongodb/lib/core/connection/connect.js:365:5) at Object.onceWrapper (events.js:300:26) at Connection.emit (events.js:210:5) { name: 'MongoNetworkError', [Symbol(mongoErrorContextSymbol)]: {}

Why do I keep getting an error after each 1084 records?

tbking tbking · Accepted Answer · 2020-03-01T00:39:01

You shouldn't create a new "connection" to MongoDB on every request. Try moving the connection code outside the request handler.

await MongoClient.connect(process.env.MONGODB_URL,async function(err,db) {
router.post('/mongo-log', async(req, res) => {
     if(err)
        {
            console.log("-------------CONNECT ERROR----------");
            console.log(err);
            process.exit(1);
        }
        const dbo = db.db(process.env.MONGODB_NAME);

    try {
      let syserr = false;
      let e = null;
        await dbo.collection("mongolog").insertOne({details:req.body.details,createDate:(new Date())},function(err,res) {

          if(err)
          {
            console.log("-------------INSERT ERROR----------");
            console.log(err);
            process.exit(1);
          }

        });
      });
      if(e) throw e;
      res.status(201).send({"success":true})
    } catch (error) {
        console.log(error);
        res.status(400).send(error)
    }

  })

MongoDB connection error after 1084 inserts from NodeJS

1 Answers