[bognition]

Hard agree with this article. Split up your application by domains, create public apis between modules, understand your dep tree and keep it clean.

The devil in the details is how you pull something like this off. At the end of the day is boils down to how do you enforce that your team does the right thing. You can have a single person that enforces standards with an iron fist, but this doesn't scale. You can teach everyone how this should work, but you're going to experience drift over time as people come and go. Or you can enforce it using technology and automation.

In the cases of the first choice, its going to restrict how big your team can get and will end up eating all of the time of your one person.

In the case of the second choice, a combination of the tragedy of the commons and regression to mean will degrade the system to spaghetti code.

For the third scenario language choice matters here a lot. In Java with multi maven modules you can setup maven to forbid imports of specific module types allowing you to make modules as private/public. In Python you can't do any of this.

[stingraycharles]

As with all of these things, it needs to come from the very, very top, otherwise it doesn’t work.

In the end, AWS only happened because of Jeff Bezos’ infamous “all intra-team communication now goes over HTTP, no exceptions, or you’re fired”-email.

The decision to prefer modules whenever they do the job, and defer only to microservices whenever they don’t, seems like the kind of mantra that needs to come from the CTO and made part of the company culture’s DNA.

[kevstev]

I think the real win with microservices is that when you are air-gapped between services, it really forces modularity and independence. Almost all the time in monoliths things slowly degrade into tangled dependencies. Once clean interfaces that just required a few specific parameters got lazy at some point and now the entire customer or order (or whatever) object is passed in and oops now the two are coupled.

This is of course still possible with a microservices architecture, but the barrier to changing a rest contract/API is usually much higher, and people think a lot more about what is being passed across the interface since that data is going to be sent over a wire.

Theoretically there is no difference, but its just far easier to slip when its one codebase and all it takes is someone a little too "LGTM" happy to let it through.