hapi-message-manager

Hapi amqp message manager

A hapi-rascal https://github.com/sitamet/hapi-rascal driver. A wrapper for event management with keys based on the structure 'dom.obj.act.det'

• dom: domain where the event occurs or the command is targetted
• obj: object the message carries.
• act: action: [event|error|cmd command].
• det: action detail.

This service driver exposes:

• publish: a method used to publish events.
• Routing: a class that helps us to manage a message.
• subscribeThisProcessor: a method used to link an event message digest to a subscription.

IMPORTANT: this module is in design stage.

Dependencies

hapi-message-manager is a driver loaded by hapi-rascal https://github.com/sitamet/hapi-rascal (the amqp rascal plugin for hapijs).

Install

npm install hapi-rascal --save
npm install hapi-message-manager --save

Config

When starting your hapijs server, register this module after hapi-rascal:

{ register: require('hapi-rascal'), options: config.rascal },
...

where config.rascal config contains the driver options:

{
    'defaults': {...},
    'vhosts': {
        'test': {
            'connection': {...},
            'exchanges': {...},
            'publications': {
                'dom.obj.act.det': {...}
            },
            'queues': {...},
            'bindings': [...],
            'subscriptions': {...}
        }
    },
    'drivers': [{
        module: 'hapi-message-manager',
        name: 'events',
        options: {
            publication: 'dom.obj.act.det'
        }
    }]
}

Usage

This message-manager service gets exposed in drivers name under rascal plugin server.plugins.rascal.events

How to link a processMessage digest to a subscription:

To subscribe processMessage to our named subscription entity-product.tasks:

function processMessage(message, content, ackOrNack) {
    // message digest
}

server.plugins.rascal.events.subscribeThisProcessor(processMessage, 'entity-product.tasks');

How to publish a message:

server.plugins.rascal.events.publish({ 'foo': 'bar' }, 'test-domain.foo.cmd.update-foo');

// now you can await for its delivery:

try {
    await server.plugins.rascal.events.publish({ 'foo': 'bar' }, 'test-domain.foo.cmd.update-foo');
}
catch(err) {
    server.log('error', err);
}

How to deal with a message with the help of Routing:

let routing = server.plugins.rascal.events.Routing(message, content);

// routing provides getters to deal with all key segments based on structure 'dom.obj.act.det'
// i.e for a given key ´domain-one.object-type-a.cmd.do-something´ keyBare give us 'object-type-a.cmd.do-something'
switch (routing.keyBare()) {

    case 'object-type-a.cmd.do-something':
        // once exec the rounting delivers the 'object-type-a.event.do-something-done'
        // and if there is an err the 'object-type-a.error.do-something'
        doSomething(content.objectTypeA.id).exec(routing.reply.bind(routing));
        break;

    case 'object-type-b.cmd.update-b':

        // once updateB calls back, routing sets new content if no err
        // and reply emits a done with key object-type-b.event.update-b-done or
        // object-type-b.errir.update-b if the updateB fails
        updateB(content.objectTypeB, (err, objectTypeB) => {
            routing.setContent(err ? null : { objectTypeB }).reply(err);
        });
        break;
}

Running the tests

npm test