SaFi Bank Space : Communication protocol between microservices

Status	COMPLETE
Impact	HIGH
Driver	Juraj Macháč (Unlicensed)
Approver	Ion Mudreac
Contributors	Jan Görig (Unlicensed) Slavomír Kocka (Unlicensed)
Informed
Due date	21 Mar 2022
Resources

Background

We are building an architecture based on microservices. Hence, it’s expected there will be a lot of communication between them. We need to choose a proper protocol. The most obvious protocols to choose from were gRPC and REST. Generally, gRPC seems to be more performant, but the team does not have experience with it.

The protocol will be used by the services, and it is expected that we will create a GQL service layer between the services and Frontend to provide a unified service which the FE will call, and also to make the FE save some networking.

Options considered

gRPC

REST

Description

Performance-oriented protocol over HTTP2 based on protobuffers

Standard representational state transfers. JSON over HTTP.

Pros and cons

better performance

shorter definitions, less boilerplate

contract first by definition

native data types

easy service creation without Spring Boot

no experience with it across the team

only fresh libraries supporting generating a GQL layer

well known across developers

simple to use in Spring Boot

accessible using external tools (e.g. curl). But there seem to be some tools for gRPC as well

better debug possibilities

less fear of the unknown

potentially worse performance

Estimated cost

MEDIUM

Action items

Outcome

REST was chosen for its broader use in the community, as well as having better support for tooling such as generating the GQL layer.

The performance downsides should be possible to minimize by leveraging the HTTP2