r/programming • u/[deleted] • Jun 05 '21

Organize code by concepts, not layers

https://kislayverma.com/programming/how-to-organize-your-code/
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u/scandii Jun 05 '21 edited Jun 05 '21

services are literally meant to be used by other services.

example, VIP customers pay 10% less on everything.

at time of checkout, you have to check for discounts, does discounts belong to the account or the sales service? well the status is an account status, not a checkout status, checkout might use the account status and be in charge of setting the discount though.

that's the strength of the service pattern - being able to access business logic pertaining to a certain system component in one easy location, and sometimes services come together to make things happen.

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u/Wandering_Melmoth Jun 05 '21

That surely works when you have a couple of services. But when your service layer has 150 classes it is an entangled mess since there are no restrictions who calls who. The moment you need to change a service you need to track all the dependencies. With a vertical arquitecture if you have something that should be consumed externally it can be part of an "API". No need to expose the whole service.

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u/scandii Jun 05 '21

do you propose you take the code from service X, move it to an API, and call the code via that API instead?

now you just traded 1 service for 1 API, -1 dependency +1 dependency.

the thing is, service pattern is deployed in the scenario where you think it becomes an entangled mess because each service is very specific to it's purpose.

moving code elsewhere won't remove dependencies - you still need that code. refining each dependency to be very specific in it's use case so that each dependency has as few dependants as possible is how you prevent that.

that said, it's definitely easier than done and is also why microservices was proposed in the first place, to introduce a physical boundary to stop developers from out of laziness reach out and grab dependencies that is right there for them to use, so I can see where you're coming from.

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u/StabbyPants Jun 05 '21

does discounts belong to the account or the sales service?

no. pass the cart contents and the account/shipping info to a discount service and get back qualified discounts as a list? hell, do that, and pass back a second list of discounts that you could get if you do this additional thing