AWS: API gateway 502 error randomly with Runtime segmentation faults - amazon-web-services

Question

I am using AWS and have an api which is called via API gateway which calls a node.js lambda function.
Very often but randomly I get 502 responses but when I immediately try again with the exact same request I get a normal response. So I decided to search the logs to see if I could find any issues.
The following is what I found for 1 of the requests:
RequestId: xxxxx Error: Runtime exited with error: signal: segmentation fault Runtime.ExitError
as well as:
xxxx ERROR Uncaught Exception
{
"errorType": "Error",
"errorMessage": "Quit inactivity timeout",
"code": "PROTOCOL_SEQUENCE_TIMEOUT",
"fatal": true,
"timeout": 30000,
"stack": [
"Error: Quit inactivity timeout",
" at Quit.<anonymous> (/opt/nodejs/node_modules/mysql/lib/protocol/Protocol.js:160:17)",
" at Quit.emit (node:events:527:28)",
" at Quit.emit (node:domain:475:12)",
" at Quit._onTimeout (/opt/nodejs/node_modules/mysql/lib/protocol/sequences/Sequence.js:124:8)",
" at Timer._onTimeout (/opt/nodejs/node_modules/mysql/lib/protocol/Timer.js:32:23)",
" at listOnTimeout (node:internal/timers:559:17)",
" at processTimers (node:internal/timers:502:7)"
]
}
the following is my reusable sql connector:
const CustomSecret = require('../secrets/CustomSecret');
const mysql = require("mysql");
module.exports = class MySqlConnect {
databaseCredObject;
constructor() {
}
async queryDb(sql, args) {
if (!this.databaseCredObject) {
await this.fetchSecret();
}
let connection = null;
const connection_settings = {
host: this.databaseCredObject.host,
user: this.databaseCredObject.username,
password: this.databaseCredObject.password,
database: 'logbook'
};
connection = mysql.createConnection(connection_settings);
return new Promise((resolve, reject) => {
connection.connect(function (err) {
if (err) {
console.log('error when connecting to db:', err);
} else {
console.log('Connected');
connection.query(sql, args, function (err, result) {
connection.end();
if (err) {
return reject(err);
}
return resolve(result);
});
}
});
});
}
async fetchSecret() {
const databaseCredString = await CustomSecret.getSecret('secretname', 'eu-west-2');
this.databaseCredObject = JSON.parse(databaseCredString);
}
}
Finally this is an example of my lambda function (shortened version):
const {compress, decompress} = require("compress-json");
const MySqlConnect = require("customPackagePath/MySqlConnect");
const CustomJwt = require("customPackagePath/CustomJwt");
const AWS = require("aws-sdk");
const warmer = require("lambda-warmer");
exports.handler = async (event) => {
if (await warmer(event)) {
console.log("Warming");
return 'warmed';
}
let responseCode = 200;
let response = {};
response.headers = {
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*'
};
const bodyContent = JSON.parse(event.body);
const dataType = bodyContent.dataType;
const webAuth = new CustomJwt();
const decodedToken = webAuth.decodeToken(event.headers.Authorization);
const userUUID = decodedToken['uuid'];
const connection = new MySqlConnect();
let sql;
switch (dataType) {
case 'userPreferences':
sql = await connection.queryDb('SELECT * FROM user WHERE uuid = ?', [userUUID]);
break;
}
let data = [];
for (let index in sql) {
data.push(JSON.parse(JSON.stringify(sql[index])));
}
const returnData = {
data
};
let compressed = compress(returnData);
response.statusCode = responseCode;
response.body = JSON.stringify(compressed);
return response;
};
Now I am new to infrastructure stuff. But it seems to me that once a lambda function has been called, its not closing or ending correctly. Also I am using the lambda warmer to keep the functions warm as seen in the lambda code and not sure if that is causing any issues.
Appreciate any help with this as I can't seem to figure it out.
Thanks

Answer 1

After doing more research I decided to add this to my Lambda function:
exports.handler = async (event, context, callback) => {
and the return like this
callback(null, response);
and ever since this issue seems to have been resolved. I am not entirely sure why but for now its looking good :)