Design of the service responsible for dispatching orders to participating businesses
Proposed
In the Non-functional requirements we described why ease of integration is crucial to the success of Hey, Blue!. To fulfill this requirement we decided to let Hey, Blue! handle all the order stuff. Businesses are just required to post their offerings via a webform and to ship received orders to the customer. For sending the order to the Business we have a dedicated Dispatcher service. This service must be designed to easily integrate many different kinds of businesses.
The Dispatcher service will follow the pattern of a Microkernel architecture. The core system is responsible for taking orders, updating their state and posting notifications about shipment state. It is connected asynchronously to the Order and Notification services. The Dispatcher service is expandable by Plugins where each Plugin represents one participating Business. The plugin is responsible to place Hey, Blue! orders at the respective Business.
This architecture makes onboarding of new Businesses easy and allows the system to integrate all thinkable kinds of interfaces. Larger Businesses may expose some kind of API to place Orders but smaller Businesses may take Orders by Mail or even Phone or Fax. For each new Business the Hey, Blue! team has to develop a new Plugin with customized code that supports the specialized needs of the Business. This way the participation in Hey, Blue! is very inclusive and no Business is excluded.