Connection fails: Error: connect ETIMEDOUT

Question

I am using Loopback with MySql. I am getting following error randomly when I run

nodemon .

or

node .

Web server listening at: http://0.0.0.0:3000
Browse your REST API at http://0.0.0.0:3000/explorer
Connection fails: Error: connect ETIMEDOUT
It will be retried for the next request.
events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: connect ETIMEDOUT
    at PoolConnection.Connection._handleConnectTimeout

1. How should I fix this issue? On Loopback side configuration or MySQL configuration? NOTE: I am using MAMP for MySQL.
2. It takes lot of time to start successfully without error. What should I do to fast restart?

Answer 1

This seems to be a known issue with MySQL and Loopback that causes the connection to time out under heavy load when Loopback is first starting:

https://github.com/strongloop/loopback-connector-mysql/issues/210

A few possible solutions:

• If you're running on a VM or container, increasing the CPU resources may fix the issue.

• Set connectTimeout and acquireTimeout in the datasource configuration (adjust the values as needed):

  {
  "mySQL":{
      //...
      "connectTimeout": 20000,
      "acquireTimeout": 20000
  }
  

  (https://github.com/strongloop/loopback-connector-mysql/issues/210#issuecomment-258089303)

• Here's another option:

  Our solution was to remove the initial database connection from the loopback boot by enabling lazyConnect in the datasource config, and then to separately call the datasource connection after the boot is finished. We came to a similar conclusion that CPU stress during the loopback boot causes the db connection to fail.

  (https://github.com/strongloop/loopback-connector-mysql/issues/210#issuecomment-758091028)

Answer 2

The most probable cause might be that some other service is using the same port, change the port.

I had similar issue with nodemon not with node though, because of not having system32 folder in my path variable.