Pursue

For events and triggers using AWS SQS.

Environment Setup

1. QUEUE_URL: The url link to the queue. (SQS url)
2. QUEUE_CALLBACK_URL: The url that is called by queue.
3. AWS_SQS_REGION: Region of AWS queue
4. AWS_SQS_API_VERSION: SQS API version

How to use

1. Create a object with key as name of handler and value as function that should run when the handler is called.

    const handlers = {
        sendEmailToBuyer: (args) => console.log(`Thank you for buying the product: ${args.productName} with us.`),
        sendEmailToSeller: (args) => console.log(`Congratulations! Your product ${args.productName} is purchased.`)
    }

2. Pass the handler object as argument while creating class Handler

   import { Handler } from '@maskeynihal/pursue';
   
   // const handlers = {} define the handler function as given in step 1.
   
   const handlerClass = new Handler(handlers)

3. Create a event and handler mapper object.

   // const handlerClass = new Handler(handlers)
   
   const eventHandlerMapper = {
    productSold: [
        handlerClass.keys.sendEmailToBuyer,
        handlerClass.keys.sendEmailToSeller
    ]
   }

4. Pass the eventHandlerMapper object as argument while creating class EventHandlerMapper

   import { EventHandlerMapper } from '@maskeynihal/pursue';
   
   // const eventHandlerMapper = {}
   
   const eventHandlerMapperClass = new EventHandlerMapper(eventHandlerMapper)

5. Create a new class Job and pass the two classes Handler and EventHandlerMapper as argument

   import { Job } from '@maskeynihal/pursue';
   
   // handlerClass
   // eventHandlerMapperClass
   
   const job = new Job(handlerClass, eventHandlerMapperClass);

6. Create a route file to handle the callback from the queue

   // import the instance of job
   // import job from './job';
   
   // using express
   router.get('/api/queue/callback', (req, res) => {
       job.dispatch(req.body.scope, req.body.data);
   
       res.json({
           message: "Dispatched!"
       })
   });

Triggering Event

The instance of the class Job should be exported from a file so that it's always pointing to same class (singleton).

All the event key can be found from the instance of class Job. Event can be triggered calling the trigger function from instance of the class.

// Get the required key
import job from './job';

const eventKey = job.events.productSold;

job.trigger(eventKey, {
    productName: "Macbook 16 inch"
});