Multiple service reproduction for turborepo

This reproduction is meant to illustrate that a change in a package used by one service can cause a rebuild in many other services.

flowchart LR
  service_d --> service_c
  service_c --> service_b
  service_b --> service_a

Loading

Scope

This repository is an extreme case where the dependency is completely linear. The APIs are also very minimal, in reality there would be many endpoints calling many other APIs, and services. In reality many different kinds of communication might also be involved such as RPC, Kafka, GraphQl, and more, this repository only has HTTP.

A more realistic example might look more a little like this:

flowchart TD
  gateway
  payment
  account
  stock
  catalog
  marketing
  admin
  user
  order
  kafka

  gateway --> account
  gateway --> stock
  gateway --> order
  gateway --> catalog

  gateway --> admin
  gateway --> user

  order --> account
  order --> payment
  order --> stock

  order --> kafka
  payment --> kafka
  kafka --> stock
  kafka --> marketing

  account --> user
  account --> admin

  catalog --> stock

  admin --> user
  marketing --> user

Loading

Yet, even in this example, there are some long chains. A change to the user service, that requires no change in any other service, would result in many unnecessary rebuilds, and deploys:

• marketing
• admin
• account
• gateway
• kafka
• payment
• order

Introduction

This repository has 4 services, a, b, c, and d. Each service has 3 packages, api, infra, and sdk. The infra package for a has a string constant, which is used to introduce a change in the reproduction. The infra package for b, c, and d contain a call to the previous API, using it's SDK. The api package contains a NestJS API, that uses the infra package. The sdk package contains an SDK generated based on an openapi.json file generated by the API.

When started, and the d API is called on http://localhost:3003 it makes a call to service c. Service c makes a call to b. Service b makes a call to service a. Service a returns the string in the services/a/infra/src/index.ts file.

Setup

Requires java because openapi-generator requires it. I used node 20.15.0 and Pnpm 9.9.0. I also included a Makefile, because it's very nice.

Reproduction

1. pnpm i
2. turbo run build
3. turbo run build --> full turbo
4. Change one character in the services/a/infra/src/index.ts file
5. turbo run build --> only 1/25 cached tasks (a polyfill package)
6. turbo run build --> full turbo
7. Change one character in the services/a/infra/src/index.ts file
8. turbo run build generate_sdk generate_metadata generate_openapi --only --filter=@multi-service-repro/service-a-* --> 0/6 cached tasks
9. turbo run build --> 2/25 cached
10. turbo run build --> full turbo
11. Try anything you like to make it work :)