Mongoose script doesn't terminate properly

Question

I have a node.js script that I want to run periodically that writes to mongodb using mongoose. It connects to mongodb, writes, and disconnects. The problem is that the script seems to hang sometimes. I have to manually terminate the script (ctrl+C).

mongoose.connect(MONGODB_URL);

var db = mongoose.connection;
db.on('error', function(err) {
    console.log(err);
});
db.on('open', function() {
    console.log('opened');
});
db.on('close', function() {
    console.log('closed');
});

Model.update(....., function(err) {
    if (err) throw err;
    mongoose.disconnect();
});

Everything seems to be fine. The script prints opened and closed and updates the database correctly, but doesn't terminate after that. I also disconnect inside the callout after all updates to the database are done so there shouldn't be any pending queries that would prevent the script from terminating.

A similar question was asked here: Properly close mongoose's connection once you're done But it doesn't look like there were any true solutions.

EDIT:
I can get it to terminate by adding process.exit() at the end, but that shouldn't be the case.

This exited fine when I tried it, so the problem is likely elsewhere in your code. — JohnnyHK, Dec 06 '15 at 16:58

score 2 · Answer 1 · answered Dec 05 '15 at 02:46

2

mongoose.connection.close() works for me but you need to make sure all your db operations have completed before calling it.

answered Dec 05 '15 at 02:46

Kunal Kapadia

3,223
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36

Raffi · Answer 2 · 2021-07-24T18:45:54.840

Here's a sample script for accessing a Mongo database:

const { Model } = require("../models");
const mongoose = require("mongoose");

async function run() {

    let c = `mongodb://${process.env.DBUSER}`;
    c += `:${process.env.DBPASS}`;
    c += `@${process.env.DBHOST}`;
    c += `:${process.env.DBPORT}`;
    c += `/${process.env.DBNAME}`;
    await mongoose.connect(
      c,
      { useNewUrlParser: true, useUnifiedTopology: true },
      () => {}
    );
    const db = mongoose.connection;
    db.on("error", console.error.bind(console, "MongoDB connection error:"));

    const instances = await Model.find({});
    for (const i of instances) {
      console.log(i.title);
    }

    mongoose.connection.close();
}


run().catch((error) => console.log(error.stack));

If this is saved in a file like script.js, just run node script.js.

Mongoose script doesn't terminate properly

2 Answers2