AWS Lambda function sometimes getting error when axios call API

Question

My Lambda function returns errors sometimes when call an API. (there is 2 different APIs that Lambda calls in same time)

There is very interesting that I put some console.log's before start API call but when Lambda starts it's return error immediately without printing any log and getting 2 type errors:

{
    “errorType”: “Runtime.UnhandledPromiseRejection”,
    “errorMessage”: “Error: socket hang up”,
    “trace”: [
        “Runtime.UnhandledPromiseRejection: Error: socket hang up”,
        ”    at process.<anonymous> (/var/runtime/index.js:35:15)“,
        ”    at process.emit (events.js:310:20)“,
        ”    at processPromiseRejections (internal/process/promises.js:209:33)“,
        ”    at processTicksAndRejections (internal/process/task_queues.js:98:32)”
    ]
}


{
  “errorType”: “Runtime.UnhandledPromiseRejection”,
  “errorMessage”: “Error: Client network socket disconnected before secure TLS connection was established”,
  “trace”: [
    “Runtime.UnhandledPromiseRejection: Error: Client network socket disconnected before secure TLS connection was established”,
    ”    at process.<anonymous> (/var/runtime/index.js:35:15)“,
    ”    at process.emit (events.js:310:20)“,
    ”    at processPromiseRejections (internal/process/promises.js:209:33)“,
    ”    at processTicksAndRejections (internal/process/task_queues.js:98:32)”
  ]
}

Note1: API is another Lambda function with same domain with proxy in Api Gateway but I checked that API always returns data as expected.

Note2: where is no any logs in CloudWatch based on this error.

Note3: Lambda running on Node v12, RAM is more that 3000 MB, and timeout is 60 seconds.

Note4: I commented one of 2 API's and right now getting below error:

{
     "errorType": "Runtime.UnhandledPromiseRejection",
     "errorMessage": "Error: read ECONNRESET",
      "trace": [
      "Runtime.UnhandledPromiseRejection: Error: read ECONNRESET",
      "    at process.<anonymous> (/var/runtime/index.js:35:15)",
      "    at process.emit (events.js:310:20)",
      "    at processPromiseRejections 
  (internal/process/promises.js:209:33)",
      "    at processTicksAndRejections 
  (internal/process/task_queues.js:98:32)"
    ]
  }

Handler:

'use strict'
console.log("in APP 1");
const awsServerlessExpress = require('aws-serverless-express');
console.log("APP 2");

//express app
const app = require('./start-server');
console.log("in APP 3");

const binaryMimeTypes = [
    'application/json',
    'text/html',
];
console.log("in APP 4");

const server = awsServerlessExpress.createServer(app,null,binaryMimeTypes);

console.log("in APP 5");

exports.handler = (event, context) => awsServerlessExpress.proxy(server, event, context)

Note5:

I can reach to APIs bu url always (as I tested right now there is no problem in responses but maybe 10 minutes later returns error, who knows) but I start to test in Api gateway in AWS panel and sometimes start getting below error:

Endpoint response body before transformations: {"Message":null}

I'm not really sure that Lambda is a stable platform.

In this Lambda I'm using ExpressJS and using Sequelize as ORM.

score 0 · Accepted Answer · answered Jul 28 '20 at 18:26

Ok, so there is 2 different problem was in here:

Lambda wrapping whole the application and starts handling errors such as Promise errors.

in order to prevent making internal server error in client side we have to mention .catch() after .then() function.

The another problem was Lambda function that representing our API (pull data from RDS by Sequelize and return as JSON). we still getting Message: null error but I think it must related to connection count to RDS or non-closed mySQL connections.

AWS Lambda function sometimes getting error when axios call API

1 Answers1