I've built a Node.js API that connects to a MySQL database. I use node-mysql2 as driver. The API and the database run in separate Docker container. At some point after deployment in a Kubernetes cluster I get the following error:
Error: Can't add new command when connection is in closed state
at PromiseConnection.query (/usr/src/app/node_modules/mysql2/promise.js:92:22)
I wonder why this error happens and how to catch and handle it using Node.js. These are code snippets of my Node.js API:
const mysql = require('mysql2/promise')
...
async function main() {
try {
const client = await mysql.createConnection({
host: DATABASE_HOST,
port: DATABASE_PORT,
user: DATABASE_USERNAME,
password: DATABASE_PASSWORD,
database: DATABASE_NAME
})
client.on('error', error => {
process.stderr.write(`${error.code}\n`) // PROTOCOL_CONNECTION_LOST
process.stderr.write(`An error occurred while connecting to the db: ${error.message}\n`)
process.exit(1)
})
} catch (error) {
process.stderr.write(`Error while creating db connection: ${error.code}\n`)
}
...
}
...
main().catch(err => {
process.stderr.write(`Error message: ${err.message}\n`)
process.exit(1)
})
Do you have an idea how to handle this error?
Do you close the connection after finishing with it?
client.end();
Also considered using a pool?
const pool = mysql.createPool({
host: DATABASE_HOST,
user: DATABASE_USERNAME,
database: DATABASE_NAME,
waitForConnections: true,
connectionLimit: 10,
queueLimit: 0
});
More info about pools: https://github.com/sidorares/node-mysql2#using-connection-pools
Related
I'm getting this error while accessing SQL Server database from aws-lambda. Everything works fine from local machine.Only having access issue when executing the code from lambda.
ConnectionError: Failed to connect to 10.2.3.44\SQLSRVR code: ETIMEOUT
This is my code snippet, any help would be appreciated!
const { Sequelize } = require('sequelize');
const sequelize = new Sequelize('DBname', null, null, {
dialect: 'mssql',
host: '10.2.3.44', //MSSQL Server IP sample
dialectOptions: {
authentication: {
type: 'ntlm',
options: {
domain: 'addidas',
userName: "uname",
password: "pwd"
}
},
options: {
instanceName: 'SQLSRVR'
}
}
})
async function connect() {
try {
await sequelize.authenticate();
console.log('Connection has been established successfully.');
} catch (error) {
console.error('Unable to connect to the database:', error);
}
}
connect();
It was because of the network restrictions only, as assumed. So had to assign lambdas in the same network which SQL server is hosted.
Thanks for all the suggestions.
I wrote a little service in NodeJS which connects to SQL Server.
In my local machine, the connection is established successfully.
After putting my files in a remote machine, I get this error:
ConnectionError: [Microsoft][ODBC Driver Manager] Data source name not
found and no default driver specified
I use windows authentication but when the username didn't have permissions, I got a different error.
const mssql = require("mssql/msnodesqlv8");
const mypool = new mssql.ConnectionPool({
driver: 'msnodesqlv8',
server: myhost,
database: mydb,
port: 1443,
options: {
trustedConnection: true,
enableArithAbort: true
}
});
mypool.connect().then(pool => {
console.log('Connected to MSSQL (DB: mydb)');
return pool;
}).catch(err => console.log('Database Connection Failed! Bad Config: ', err))
Try modifying the connection pool as below,
const pool=new sql.ConnectionPool (config, function(err){
if(err){
console.log('Error while creating connection pool \n'+err);
}
});
I'm tyring to make a connection from my nodejs script to my db connection, but seems like there is a suspicius issue i'm not able to figure out.
At the moment, this is my code:
const { Pool } = require('pg');
const pool = new Pool({
user: 'user',
host: '192.168.1.xxx',
database: 'database',
password: 'password',
port: 5432,
});
pool.on('error', (err, client) => {
console.error('Error:', err);
});
const query = `SELECT * FROM users`;
pool.connect()
.then((client) => {
client.query(query)
.then(res => {
for (let row of res.rows) {
console.log(row);
}
})
.catch(err => {
console.error(err);
});
})
.catch(err => {
console.error(err);
});
The issue seems to be in pool.connect(), but i can't understand what i'm missing because i got no errors in the log. I've installed pg module in the directory of my project with npm install --prefix pg and i know modules are loaded correctly.
I edited postgresql.conf:
# - Connection Settings -
listen_addresses = '*'
and pg_hba.conf
host database user 192.168.1.0/24 md5
to make the database reachable via lan and seems liek it works, because i'm able to connect successfully with apps like DBeaver...but i can't with NodeJS.
It's possible there is some kind of configuration i've to active?
I installed "pg": "^8.0.2" and created the database.js file with database credentials. But no matter what go wrong it never enters in the catch block to show error. Instead it always logs connected to the database. Can anyone point out what I'm doing wrong. Thank You!
Database.js
const Pool = require('pg').Pool;
const pool = new Pool({
user: 'roothjk',
host: 'localhost',
database: 'sf',
password: 'admin',
port: 5432
});
try {
pool.connect()
console.log('connected to the db');
} catch (e) {
console.log('Error connecting to db');
}
connect returns a Promise, and then you move to the next statement. Instead, you should use the then and cath methods:
pool.connect()
.then(c => console.log('connected to the db'))
.catch(e => console.log('Error connecting to db'));
I have recently deployed my node.js API application on live server. I am getting these issue on live server.
I have googled it, but could not get any exact solution. Can anyone suggest how can i solve this problem?
{ Error: read ETIMEDOUT at TCP.onread (net.js:622:25) errno: 'ETIMEDOUT', code: 'ETIMEDOUT', syscall: 'read', fatal: true }
{ Error: Can't add new command when connection is in closed state at PoolConnection._addCommandClosedState }
I amd using the mysql connection pool like this
var mysql = require('mysql2');
var mysqlPool = mysql.createPool({
host: 'localhost',
user: 'root',
password: 'xyz',
database: 'xyz',
waitForConnections: true,
connectionLimit: 10,
queueLimit: 0
});
module.exports = mysqlPool;
I had a similar problem and ended up having to put the connection request in it's own .js file and import it into the controller-
connectionRequest.js
module.exports = function () {
let mysql = require('mysql2')
let connCreds = require('./connectionsConfig.json');
//Establish Connection to the DB
let connection = mysql.createConnection({
host: connCreds["host"],
user: connCreds['username'],
password: connCreds['password'],
database: connCreds['database'],
port: 3306
});
//Instantiate the connection
connection.connect(function (err) {
if (err) {
console.log(`connectionRequest Failed ${err.stack}`)
} else {
console.log(`DB connectionRequest Successful ${connection.threadId}`)
}
});
//return connection object
return connection
}
Once I did that I was able to import it into my query on the controller file like so
ControllerFile.js
let connectionRequest = require('../config/connectionRequest')
controllerMethod: (req, res, next) => {
//Establish the connection on this request
connection = connectionRequest()
//Run the query
connection.query("SELECT * FROM table", function (err, result, fields) {
if (err) {
// If an error occurred, send a generic server failure
console.log(`not successful! ${err}`)
connection.destroy();
} else {
//If successful, inform as such
console.log(`Query was successful, ${result}`)
//send json file to end user if using an API
res.json(result)
//destroy the connection thread
connection.destroy();
}
});
},
After a lot of messing around I was able to solve the problem by destroying the connection, waiting (this is the important page) and getting the connection again.
conn = await connPool.getConnection();
// We have error: Can't add new command when connection is in closed state
// I'm attempting to solve it by grabbing a new connection
if (!conn || !conn.connection || conn.connection._closing) {
winston.info('Connection is in a closed state, getting a new connection');
await conn.destroy(); // Toast that guy right now
sleep.sleep(1); // Wait for the connection to be destroyed and try to get a new one, you must wait! otherwise u get the same connection
conn = await connPool.connection.getConnection(); // get a new one
}