In the previous section, we looked at accepting a new product order in an orchestration and returning a response to the submitter. What if we only want a one-way channel and want multiple consumers to subscribe to this new order? This screams for a more event-driven scenario where the publisher asynchronously sends data that is handled and acted upon by unknown downstream systems (for example, fulfillment systems and billing systems). In this case, we aren't interested in creating an orchestration that dictates our service contract but rather want to build a service on-ramp that simply gets data onto the message bus.
For this scenario, we will do the following: