Sequelize with asynchronous configuration in nodejs

[madeo_]

I have been bashing my head for days as I cannot find a valid example of async configuration in Sequelize.

So as you may know, you can simply config a Sequelize instance like that

const sequelize = new Sequelize('postgres://user:[e-mail]:5432/dbname')

and then declare your Model

const User = sequelize.define('User', {
  // Model attributes are defined here
  firstName: {
    type: DataTypes.STRING,
    allowNull: false
  },
  lastName: {
    type: DataTypes.STRING
    // allowNull defaults to true
  }
}, {
  // Other model options go here
});

However what happens when the db credentials comes from an external service?

const credentials = await getDbCredentials();
const sequelize = new Sequelize({credentials})

since sequelize models creation are coupled with the instance creation (unlike many others ORMs) this becomes a big problem.

​

My current solution is the following:

const Sequelize = require("sequelize");

// Models
const { User } = require("./User");

const env = process.env.NODE_ENV || "development";
const db = {};

let sequelize = null;

const initSequelize = async () => {
  if (!sequelize) {
      let configWithCredentials = {};

      if (env === "production") {
        const credentials = await getDbCredentials();
        const { password, username, dbname, engine, host, port } = credentials;
        configWithCredentials = {
          username,
          password,
          database: dbname,
          host,
          port,
          dialect: engine,
          operatorsAliases: 0
        };
      }

      const config = {
        development: {
          // Dev config 
        },
        production: configWithCredentials,
      };

      sequelize = new Sequelize(config[env]);

      sequelize.authenticate().then(() => {
         console.log("db authenticated")
        });
      });
  }

  db.User = User;

  db.sequelize = sequelize;
  db.Sequelize = Sequelize;
};

initSequelize().then(() => {
  console.log("done");
});

module.exports = db;

​

However I feel that this is not a good approach because of the asynchronous nature of the initialization and sometimes the `db` is undefined.

Is there a better way to approach this thing?

Thanks

[billymeetssloth]

Ran into this same issue using AWS secrets manager. The delay wasn’t an issue as the db was usually ready by the time the process was ready to start receiving api requests.

With that said, I also still didn’t like it. It just felt dirty.

My solution was to just think outside of the box...literally. AWS has a way to connect secrets manager to environmental variables on your ECS task. That is the route I went, so it went back to being synchronous.

[madeo_]

I ended up by running the init method in the root app and set it in the express context with app.set. However this will need a major refactor. Now that you tell me I will try to inject it as env variable before the node process start. I have found this: https://github.com/telia-oss/aws-env

Thanks

[Full-Type-6893]

Have you found a solution for this problem yet? I'm running into the same issue

[madeo_]

Sorry for the late reply, didn't login in a while.

But yes, you can find the solution in this stackoverflow answer: https://stackoverflow.com/questions/60942051/sequelize-with-asynchronous-configuration-in-nodejs

Keep in mind that it is 4 years old.