Decorators

What are decorators?

Decorators is an elegant syntactic way that Python provides for extending what other functions do. Using the @ keyword one can annotate another function using such decorators.

Minos uses decorators to extend the functionality of certain methods and eliminate some boilerplate code that other way would distract the developer from its actual goal: building and application. Mainly, those decorators are used in the Command and Query services to define the means through which they are called.

Let’s consider the following example:

@enroute.broker.command("CreateProduct")
@enroute.rest.command("/products", "POST")
async def create_product(self, request: Request) -> Response:
    ...

Here we have a create_product() command, which deals with the business logic of creating a product within our system. By using the @enroute decorator, Minos extends its functionality and attaches that function to a REST endpoint as well as to an event.

Minos decorators

The @enroute decorator is divided in the following categories:

• @enroute.broker deals with event subscription. More information can be seen at Broker.

  • @enroute.broker.command(event: str) attaches the method to a command invoked through the broker.

  • @enroute.broker.query(event: str) attaches the method to a query invoked through the broker.

  • @enroute.broker.event(event: str) attaches the method to an event published by a microservice.

• @enroute.rest deals with REST endpoint definition. More information can be seen at REST.

  • @enroute.rest.command(endpoint: str, verb: str) attaches the method to a REST endpoint in the command service.

  • @enroute.rest.query(endpoint: str, verb: str) attaches the method to a REST endpoint in the query service.

• @enroute.periodic deals with periodic tasks. More information can be seen at Periodic.

  • @enroute.periodic.event(crontab: str | crontab.CronTab) attaches the method to a periodic event that will happen according to the given crontab definition.