express-http-context getting lost after calling mysql - mysql

Question

Need your help. I am trying to implement global request id for my nodejs application. For that I am using express-http-context lib to set request id. But it's not working as expected when my code access data from mysql database. Seems like there is a compatibility issue in cls used by express-http-context and mysql library.
Sample code and the output is provided below:
const app = require('express')();
const httpContext = require('express-http-context');
const mysql = require('mysql');
const { INTERNAL_SERVER_ERROR, OK, NOT_FOUND } = require('http-status-codes');
const http = require('http');
const uuidv4 = require('uuid/v4');
const pool = mysql.createPool({
host: '127.0.0.1',
port: 3306,
user: 'root',
password: 'Redhat#123',
database: 'user',
connectionLimit: 10,
});
pool.query('SELECT 1 + 1 AS solution', (error) => {
if (error) {
console.log('Unable to connect to MySQL:- ', error.message);
process.exit(1);
}
console.log('MySQL PING is Working');
});
app.use(httpContext.middleware);
app.use((req, res, next) => {
httpContext.set('requestId', uuidv4());
console.log('request Id set is: ', httpContext.get('requestId'));
next();
});
const getUserDetailsRepository = (userId, callback) => {
console.log('inside getuserDetails repository for request id: ', httpContext.get('requestId'));
pool.getConnection((connectionError, connection) => {
if (connectionError) {
console.log('got ConnError getuserDetails repository for request id: ', httpContext.get('requestId'));
callback(connectionError);
} else {
const query = 'SELECT * from user where id = ?';
connection.query(query, [userId], (queryError, results) => {
connection.release();
if (queryError) {
console.log('got queryError getuserDetails repository for request id: ', httpContext.get('requestId'), queryError.message);
callback(queryError);
} else {
console.log('Got response inside getuserDetails repository for request id: ', httpContext.get('requestId'));
callback(null, results);
}
});
}
});
};
const userGetDetails = (req, res, next) => {
const { userId } = req.params;
console.log('inside getUserDetails controller for request id: ', httpContext.get('requestId'));
getUserDetailsRepository(userId, (error, result) => {
if (error) {
console.log('got Error in getuserDetails controller for request id: ', httpContext.get('requestId'))
res.sendStatus(INTERNAL_SERVER_ERROR);
} else if (result) {
console.log('Got response inside getuserDetails repository for request id: ', httpContext.get('requestId'));
res.status(OK).json(result);
} else {
res.sendStatus(NOT_FOUND);
}
});
};
app.get('/user/:userId', userGetDetails);
const server = http.createServer(app);
server.listen(3000, () => console.log('Http server started listening on port'));
Output:
Http server started listening on port
MySQL PING is Working
request Id set is: ea4895ab-8003-4d28-99aa-b03af7027ae8
inside getUserDetails controller for request id: ea4895ab-8003-4d28-99aa-b03af7027ae8
inside getuserDetails repository for request id: ea4895ab-8003-4d28-99aa-b03af7027ae8
Got response inside getuserDetails repository for request id: undefined
Got response inside getuserDetails repository for request id: undefined

Answer 1

i hope this solution solve your problem and save many hours for anyone that have this problem
you can just use bindEmitter to solve the problem
app.use((req, res, next) => {
httpContext.ns.bindEmitter(req);
httpContext.ns.bindEmitter(res);
var requestId = req.headers["x-request-id"] || uuidv4();
httpContext.set("requestId", requestId);
console.log('request Id set is: ', httpContext.get('requestId'));
next();
});