Knex.js connection error when rerunning the function

Question

I'm using Knex to connect to an Azure database, run a query that returns the status of a database (COPYING/ONLINE). If I run this once, all is fine. But if I use a setInterval to rerun this (I want to know when the status changes from COPYING to ONLINE) I'm getting a connection error the second, and third, and.. time the function is called.

Here is my code

const knex = require('knex')({
  client: 'mssql',
  connection: {
    host: '***',
    user: '***',
    password: '***',
    options: { requestTimeout: 350000, encrypt: true },
  },
  pool: {
    min: 0,
    max: 15,
  },
});
async function copyStatus() {
  try {
    console.log('Running query');
    const status = await knex.raw(
      "SELECT name, state_desc FROM sys.databases WHERE name = 'Tide_QA_Dev_runtime' "
    );
    return status[0].state_desc;
    // console.log(status[0].state_desc);
  } catch (error) {
    console.log(error);
  } finally {
    console.log('Closing connection with database');
    await knex.destroy();
  }
}

function intervalFunc() {
  copyStatus().then(function (result) {
    if (result === 'ONLINE') {
      console.log('Database copy is done.');
    } else if (result === 'Database is still copying') {
      console.log('bezig');
    }
  });
}

setInterval(intervalFunc, 2000);

Here is my output

Closing connection with database
Database copy is done.
Running query
Error: Unable to acquire a connection
    at Client_MSSQL.acquireConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/client.js:286:13)
    at Runner.ensureConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:259:46)
    at Runner.run (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:30:30)
    at Raw.Target.then (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/builder-interface-augmenter.js:24:43)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
Closing connection with database
Running query
Error: Unable to acquire a connection
    at Client_MSSQL.acquireConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/client.js:286:13)
    at Runner.ensureConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:259:46)
    at Runner.run (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:30:30)
    at Raw.Target.then (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/builder-interface-augmenter.js:24:43)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
Closing connection with database```

It looks like the connection is made (see console log: Running query).
Any idea what's going on?

Answer 1

You should use code like below, it works for me.

const knex = require('knex')({
    client: 'mssql',
    connection: {
        // no tcp:
        server: 'j***2sqlserver.database.windows.net',
        user: 'j***2',
        password: 'J****0',
        database: 'yourdbname',
        port: 1433,
        options: { requestTimeout: 350000, encrypt: true },
    },
    pool: {
        min: 0,
        max: 15,
    },
});

My Test Result.

Answer 2

You should not call knex.destroy() if you are going to make more queries to the DB.

Move that knex.destroy() call to somewhere just before application is going to exit.