Microservices should form a polytree

vedhant wrote: post #3

This actually makes a lot of sense. I have one question though. Why is having 2 microservices depend on a single service a problem?

The explanation given makes sense. If they're operating on the same data, especially if the result goes to the same consumer, are they really different services? On the other hand, if the shared service provides different data to each, is it really one microservice or has it started to become a tad monolithic in that it's one service performing multiple functions?

I like that the author provides both solutions: join (my preferred) or split the share.

Re: Microservices should form a polytree

#5

Post by jamesbelchamber » Fri, Dec 12, 2025, 4:39 PM UTC

Good practical explanation of something I felt but couldn't put a name to.

Re: Microservices should form a polytree

#6

Post by rco8786 » Fri, Dec 12, 2025, 4:40 PM UTC

Is there any way to actually enforce this in reality? Eventually some leaf service is going to need to hit an API on an upstream node or even just 2 leaf nodes that need to talk to each other.

Re: Microservices should form a polytree

#7

Post by jayd16 » Fri, Dec 12, 2025, 4:42 PM UTC

rco8786 wrote: post #6

Is there any way to actually enforce this in reality? Eventually some leaf service is going to need to hit an API on an upstream node or even just 2 leaf nodes that need to talk to each other.

IAM roles.

Said less snarky, it should be trivial to define and restrict the dependencies of services (Although there are many ways to do that). If its not trivial, that's a different problem.

Re: Microservices should form a polytree

#8

Post by jayd16 » Fri, Dec 12, 2025, 4:44 PM UTC

It's about the same for most code all the way down to single threaded function flow.

Re: Microservices should form a polytree

#9

Post by btbytes » Fri, Dec 12, 2025, 4:51 PM UTC

mapehe wrote: post #2

Hi, this is my company blog. Hope you like this week's post.

have you read about Erlang supervision trees? https://adoptingerlang.org/docs/development/supervision_tree...

Re: Microservices should form a polytree

#10

Post by buster » Fri, Dec 12, 2025, 4:51 PM UTC

Isn't it the same wisdom as to avoid cyclic dependencies?