database-dispatcher

DatabaseDispatcher is a package that returns the necessary DB driver from a received model. Access to the databases configuration then returns the driver instance with the connection. It caches the driver per config properties.

Installation

npm install @janiscommerce/database-dispatcher

# Then install all the drivers that you need.
npm install --save @janiscommerce/mysql
npm install --save @janiscommerce/mongodb
npm install --save @janiscommerce/elasticsearch
# or any other DBDriver if it's exists

Settings

Config file with Settings package, with settings in JSON file /path/to/root/.janiscommercerc.json into the key database, clients, databaseWriteType, databaseReadType:

{
	"database": {
		"core": {
			"type": "mysql",
			"host": "http://my-host-name.com",
			"database": "my-database"
			// ...
		},
		"other": {
			"type": "mongodb",
			"host": "http://other-host-name.com",
			"database": "my-database"
			// ...
		},
		"another": {
			"type": "elasticsearch",
			"host": "http://another-host-name.com",
			// ...
		}
	},
	"databaseWriteType": "mongodb",
	"databaseReadType": "mysql",
	"clients": {
		"database": {
			"fields": {
				"write": {
					"dbHost": "host",
					"database": "collection"
				},
				"read": {
					"url": "host",
					"dbDatabase": "database"
				}
			}
		}
	}
}

Database Settings

• Keys validations depends on the DBDriver.
• type: if it's not exist, databaseWriteType will be use as default.

Client Settings

To assign Read and Write types of DBDrivers.

• databaseWriteType: Required, Type of Write Database. It's the default DBDriver for every database.
• databaseReadType: Optional, Type of Read Database.

Mapped Aliases of Clients Objects

• clients.database.fields.write: For Write DB
• clients.database.fields.read: For Read DB

Structure:

• key: Field present in Client object
• value: Field needed in DBDriver

Example

In .janiscommercerc.json

{
	"clients": {
		"database": {
			"fields": {
				"write": {
					"url": "host",
					"index": "database"
				}
			}
		}
	},
	"databaseWriteType": "elasticsearch"
}

Client Object getted from Client DB

client = {
	id: '123'
	name: 'Company',
	url: 'http://company-host-name.com',
	index: 'company.index'
}

Config will be

config = {
	host: 'http://company-host-name.com',
	databse: 'company.index'
}

API

• getDatabaseByKey(databaseKey) Receives the database key [String] and returns the database driver instance associeted to a config. If the databaseKey dosen't exists in any config source will throw a DatabaseDispatcherError. The default value of databaseKey parameter is "_default".

• getDatabaseByConfig(config) Receives the config [Object] and returns the database driver instance.

• getDatabaseByClient(clientObject, useReadDB) Receives the client object [Object] and returns the database driver instance associeted to a config. If useReadDB ([Boolean]) doesn't exists or it's FALSE will try to get Write DBDriver Type by default, if it's TRUE will try to get Read DBDriver Type. If the databaseReadType doesn't exists will use databaseWriteType. If the databaseWriteType doesn't exists will be throw a DatabaseDispatcherError.

• clearCache() Clear the internal cache, including config and DB connections.

Errors

The errors are informed with a DatabaseDispatcherError. This object has a code that can be useful for a correct error handling. The codes are the following:

| Code | Description | |------|------------------------------------------------------| | 1 | Settings not found | | 2 | Invalid settings | | 3 | ConfigDB not found for databaseKey in Settings | | 4 | Invald ConfigDB found in Settings for a databaseKey | | 5 | Invalid Client Object | | 6 | DB Driver not installed | | 7 | Invalid DB Driver (not a valid Class) |

Usage

const DatabaseDispatcher = require('@janiscommerce/database-dispatcher');

/*
	/path/to/.jannsicommercerc.json
    database: {
		core: {
        	type: 'mysql',
        	host: 'foo',
        	...
		},
		...
	},
	databaseWriteType: 'mongodb',
	databaseReadType: 'elasticsearch',
	clients: {
		database: {
			fields: {
				write: {
					dbHost: 'host'
				},
				read: {
					url: 'host',
					index: 'database'
				}
			}
		}
	},
	...
*/

// Get by Key
const myDBConnection = DatabaseDispatcher.getDatabaseByKey('core'); // A new DBDriver instance is returned.

console.log(myDBConnection); // expected output: DBDriver


// Get Write DB by Client
const client = model.getClientById('123') // Or Any method you use to get client's objects

const myDBWriteConnection = DatabaseDispatcher.getDatabaseByClient(client); // A new DBDriver instance is returned.

console.log(myDBWriteConnection.constructor.name); // expected output: MongoDB


// Get Read DB by Client
const otherClient = model.getClientById('1234') // Or Any method you use to get client's objects

const myDBWriteConnection = DatabaseDispatcher.getDatabaseByClient(otherClient, true); // A new DBDriver instance is returned.

console.log(myDBWriteConnection.constructor.name); // expected output: ElasticSearch

DatabaseDispatcher.clearCache(); // cached connections and configs cleared.