前端还是后端应该调用微服务？

Question

I am confused as to whether my frontend application should be the one calling microservices or the backend?

For example: let say I have an "App A" which uses "Auth" and "Products" services. Should my "App A" server call auth and products services? Or should my frontend call these services directly?

I think in many cases, its more correct to call my services directly since I notice otherwise, my app server endpoints is purely a proxy to these services, which is quite useless.

Answer 1

As always... it depends. If your backend is purely proxying the calls, it is kind of useless. But you could also utilize it for logging, load balancing etc. Javascript apps for example cannot run in parallel and utilize all your cores. So this could be a reason to process requests in the backend as well. There is really no one-fits-all solution.

Answer 2

The approach you mentioned aligns well with the use case of API Gateway. And it is not really just a proxy. There are way too many things you can do around that, but perhaps the most important thing is security and abstraction. By allowing frontend to access the services directly you are exposing all your services to the internet and you have to put in mechanism to tackle vulnerabilities in each one of them. It make sense to do it in one place.

Second is discovery and maintainability of endpoints which is a better with such a solution

This may add one more hop but what you could do with this in place make it worth.

Logging, routing, downtime/error handling all can be managed well if you are not exposing services directly.

Another point with respect to Auth service, it may lie behind your proxy or could be the only other service exposed. There are some benefits in either of those approaches but since its not what you asked I will trim it to this.

Having said that, in the end it all really depends on your needs and your use cases. If security is not a prime concern or if you are working more around POC. But just consider the pros and cons of having one