Authentification in just one file with Sequelize

I am trying to use Sequelize, but I don't know how to figure out that : I want to connect only one time in the start.js, and not in each file.

This is my start.js :

const Sequelize = require("sequelize");

// import environmental variables from our variables.env file
require("dotenv").config({ path: "variables.env" });

// Connect to our Database
const sequelize = new Sequelize(
process.env.DATABASE_NAME,
process.env.DATABASE_USER,
process.env.DATABASE_PASSWORD,
{
host: process.env.DATABASE_HOST,
dialect: "postgres",
operatorsAliases: false,
pool: {
max: 5,
min: 0,
acquire: 30000,
idle: 10000
}
}
);
// Try to authenticate to our databse
sequelize
.authenticate()
.then(() => {
console.log("🗄 Database connection successful !");
})
.catch(err => {
console.error("🗄 Database connection error...", err);
});

// Start our app!
const app = require("./app");
app.set("port", process.env.PORT || 7777);
const server = app.listen(app.get("port"), () => {
console.log(`🚅 Express running → PORT ${server.address().port}`);
});


And this is a random file (userController.js) when I want to execute a query :

const Sequelize = require("sequelize");
// This is the problem:
const sequelize = new Sequelize; // (.connection() ?)

exports.getUsers = async (req, res) => {
// Query the DB for a list of all users
const users = await sequelize.query("SELECT * FROM profils");
res.send({ users });
};


Thank you for your help ! : )

1 Answer
1

As the reference explains,

Sequelize will setup a connection pool on initialization so you should ideally only ever create one instance per database if you're connecting to the DB from a single process.

So there should be a single instance, likely defined in a separate module:

const Sequelize = require("sequelize");

module.exports = new Sequelize(...);


that is imported in both middleware and main modules. As the reference also states, authenticate isn't really necessary but can be used to as a step for initialization routine:

authenticate

require("dotenv").config({ path: "variables.env" });

const sequelize = require('./db');

// for testability purposes
module.exports = sequelize
.authenticate()
.then(() => {
// Start our app!
const app = require("./app");
...
// for testability purposes
return app;
})
.catch(err => {
console.error(err);
});


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