My web app uses Lambda using NodeJS and backend is RDS(MySQL). I'm using serverless-mysql to make db calls.
For some reason, the db call times out intermittently. I tried the following:
- Enabled flow logs to see if there are any errors (but couldn't find any reject statuses).
- Tried making the database publicly available and took lambda out of VPC (to see if it is an issue with VPC configuration). But still, it was failing intermittently. So VPC is out of the equation.
- RDS is not having any unusual spikes and connection exhaustion as monitoring shows a peak of only up to 3 connections. Lambda is always kept warm. I tried increasing the time out to up to 25 seconds. Still no luck.
Below is the code I use:
export async function get(event, context, callback) {
if (await warmer(event)) return 'warmed';
context.callbackWaitsForEmptyEventLoop = false;
try {
const userId = getUserIdFromIdentityId(event);
const query = "select * from UserProfile where UserId = ?";
const result = await mysql.query(query, [userId]);
console.log(result);
console.log('getting user account');
mysql.quit();
return success({
profileSettings: result.length > 0 ? result[0] : null,
});
} catch(e) {
console.log(e);
return failure();
}
}
Success function basically returns a json object like below:
return {
statusCode: 200,
headers: {
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Credentials": true
},
body: JSON.stringify(body)
};
mysql is initialized as below:
export const mysql = AWSXray.captureMySQL(require('serverless-mysql')({
config: {
host: process.env.dbHost,
user: process.env.dbUsername,
password: process.env.dbPassword,
database: process.env.database,
}
}));
The only error I can see in Cloudwatch logs is:
Task timed out after 10.01 seconds.