Sequelize Connection Manager
Creates and manages connections against a database, using sequelize.
The manager can be used to avoid having multiple connections running against the same database.
It stores each created connection in an internal connection storage and provides methods for creating and retrieving such a connection and for destroying it.
Usage
Usage is simple enough.
You need to have a valid Sequelize connection config at hand that you can pass to the manager.
With it, you can create, retrieve and close any Sequelize connection.
Create an instance
You can get an instance of the manager in one of two ways:
Manual instantiation
You can simply create an instance the usual way.
import {
SequelizeConnectionManager,
} from '@essential-projects/sequelize_connection_manager';
const sequelizeConnectionManager: SequelizeConnectionManager =
new SequelizeConnectionManager();Through IoC
The manager provides a module that can be used with addict-ioc.
The registration looks like this:
container
.register('SequelizeConnectionManager', SequelizeConnectionManager)
.singleton();It registers the manager as a Singleton component, meaning that any class that gets it as a dependency, will get the same instance.
To inject it into another class, use the following registration:
container
.register('SomeSampleRegistration', SomeSampleClass)
.dependencies('SequelizeConnectionManager');Then your class will get the manager injected into its constructor:
import {
SequelizeConnectionManager,
} from '@essential-projects/sequelize_connection_manager';
class SomeSampleClass {
private _sequelizeConnectionManager: SequelizeConnectionManager;
constructor(sequelizeConnectionManager: SequelizeConnectionManager) {
this._sequelizeConnectionManager = sequelizeConnectionManager
}
}Get a Connection
To retrieve a connection to a specific database, use the following call:
import * as Sequelize from 'sequelize';
const databaseConfig: Sequelize.Options = {
dialect: 'postgres',
database: 'sample_database',
username: 'someusername',
password: 'somepassword',
};
const sequelizeConnection: Sequelize.Sequelize =
await sequelizeConnectionManager.getConnection(config)This will get you a connection to the postgres database sample_database, using
the given credentials for authentication.
If no such connection has been established before, a new one will be created.
If a matching connection already exists, the manager will return that one instead.
Close a Connection
To close an existing connection, pass the same config to the following call:
await sequelizeConnectionManager.destroyConnection(config)Caution: Be advised that this will close the connection for any component that uses it!