Microservices best practice: Client libraries vs service mesh

[mikeparker]

Great doc on microservices best practice, I agree with most of it.

However, one thing that jumped out - it talks about client libraries and having retry behaviour, circuit breaking, logging etc inside those libraries. Have you considered having those pieces of functionality outside the containers in sidecars, so you don't need to implement the library in every language and don't need to constantly worry if you are using the latest library and hooking the various functions into the codebase correctly?

I know the document is an opinionated piece, I was just curious as to whether this should be explicitly called out as service meshes being deliberately ignored, or whether they warrant inclusion.