Architecture of a microservice based web app

web-applications soa microservices
shreyj picture shreyj · Nov 11, 2014 · Viewed 11.7k times · Source

I am confused about the point at which a web application diverges into microservices - is it at url level or models level? As an example, Suppose I have a monolithic app that serves 3 pages. Say each page serves a separate usecase and I want to back each of them with their own microservices. Now, which of these is the correct way of implementing a microservice based architecture:

  • I create three different apps(microservices), each containing the (route, controller, models, templates) for one of the pages. And then based on which ever page is requested, I route the request to that particular app. This means that the whole page from database to HTML is served by a separate app. Basically, different pages in the same website are being completely served by different apps on the backend.
  • The 3 microservices do not handle the UI stuff but only the data for their usecases(models, controller, no templates) and expose it over a REST api. I have one public facing app. This app queries the three different apps(microservices) only for the data and then builds the html pages to be returned to browser. All the pages in a web app in this case are being served by a single app which internally makes use of three different microservices.

enter image description here

Answer

DeivinsonTejeda picture DeivinsonTejeda · Dec 22, 2014

You trouble is how model your microservices.

In term of microservices the second approach is most appropriate, which expose its logic through API.

Always when you model your microservices keep in mind the follow facts.

  • Loose Coupling: When services are loosely coupled, a change to one service should not require a change to another. The whole point of this Microservice thing is being able to make a change to one service, and deploy it, independent of a need to change any other part of the system. This is really quite important.

  • Strong Cohesion: We want related behaviour to sit together, and unrelated behaviour to sit elsewhere. Why? Well, if we want to change behaviour, we want to be able to change it in one place, and release that change as soon as possible.

Related questions

How do I resolve "HTTP Error 500.19 - Internal Server Error" on IIS7.0

What causes this error, how can I fix it? Detailed Error Information Module IIS Web Core Notification BeginRequest Handler Not yet determined Error Code 0x8007052e Config Error Can not log on locally to C:\inetpub\wwwroot as user administrator …

Read More
Memcached vs. Redis?

We're using a Ruby web-app with Redis server for caching. Is there a point to test Memcached instead? What will give us better performance? Any pros or cons between Redis and Memcached? Points to consider: Read/write speed. Memory usage. …

Read More
How to decide when to use Node.js?

I am new to this kind of stuff, but lately I've been hearing a lot about how good Node.js is. Considering how much I love working with jQuery and JavaScript in general, I can't help but wonder how to …

Read More