Class: Service

Service is an abstract class which is only instantiated by layline.io itself and not for your direct use. It is directly related to the Services which you can define within layline.io. Examples are

• Cassandra Service
• JDBC Service
• Hazelcast Service
• HTTP Service
• Aerospike Service
• more

When configuring a Javascript Asset, you may also define one or more Services for use within that Javascript Asset. layline.io then exposes these assigned Services to Javascript via the services pseudo.class.

Let's assume you have a Javascript Asset with two assigned Services MyService_A and MyService_B. You can then access these Services within Javascript like this:

const SvcA = services.MyService_A;
const SvcB = services.MyService_B;

The way layline.io exposes this class is by providing an object services within a Javascript Asset. This is then used to access linked Services and their configured functions.

Let's look at this using an example:

Let's assume we have configured a Javascript Asset which is linked to A JDBC Service Asset by the name of MyDBService. The Service MyDBService has one Function MyInsert which you have defined when you set up the JDBC Service Asset using the UI.

You can access all Services which you may have linked to a Javascript Asset by using the services keyword like so:

Opening a connection:

let OUTPUT_PORT = null;
let connection = null;

// Initial setup
export function onInit() {
    OUTPUT_PORT = processor.getOutputPort('MyOutput');
}

export function onStreamStart() {
    // Open a connection to the DB service
    if (!connection) {
        connection = services.MyDBService.openConnection();
    }
    connection.beginTransaction();
}

Depending on the type of service you are addressing you have different options which you have to understand and know. A JDBC Service for example exposes a Connection whereas a HTTP Service does not.

Check the respective Service Asset documentation on how to use the Service within a Javascript Asset.

Abstract