2022

avoiding micro-monolIthS

MONOLITHIC BACKEND

HTTP Server

URL Router

View X

View Y

View Z

Model A

Model B

Database

HTTP

Function calls

Queries

The Monolith

Logic X, Y, Z

SPAGHETTI

MONOLITHIC BACKEND

component boundaries

• there is nothing wrong with monoliths

• ... provided they are well-structured

• humans tend to be lazy, incompetent and prone to errors

• humans break component boundaries and generate spaghetti over time

• let's enforce the boundaries then

NON-MONOLITHIC BACKEND

component boundaries

HTTP Server

URL Router

View X

View Y

View Z

Model A

Model B

Database

URL Router

URL Router

Model A

Model B

Model B

Business Logic

Logic X

Logic Y

Logic Z

COPY PASTA

NON-MONOLITHIC BACKEND

DATA BOUNDARIES?

HTTP Server

View X

View Y

View Z

Model A

Model B

Database B

Model A

Model B

Model B

Logic X

Logic Y

Logic Z

Database A

NON-MONOLITHIC BACKEND

data boundaries?

HTTP Server

View X

View Y

View Z

Model A

Database B

Model B

Logic X

Logic Y

Logic Z

Database A

View

B

View A

DISTRIBUTED SPAGHETTI

NON-MONOLITHIC BACKEND

distributed spaghetti

• call stack lives in the cloud:
  control flow is hard to follow
• inflexible:
  need to coordinate interface changes in multiple places
• duplicated views and clients:
  need to provide CRUD for all models used by siblings

The problem

Model A

Model B

Logic X

Logic Y

Logic Z

the solution

Logic X

Logic Y

Logic Z

Data
A

Data
B

Data
B

Data
A

Data
B

A pure function is a function that has the following properties:

1. The function return values are identical for identical arguments
2. The function application has no side effects

the solution

purity of essence

No matter what language you work in, programming in a functional style provides benefits. You should do it whenever it is convenient, and you should think hard about the decision when it isn't convenient.

John Carmack

the solution

BENEFITS OF PURITY

• Easy unit testing
• Self-documenting interface
• Straightforward control flow
• Easier memoization/caching

NON-MONOLITHIC BACKEND

DATA BOUNDARIES!

HTTP Server

View X

View B

Model A

Database B

Model B

Logic X

Database A

Data
A

Data
B

2022

avoiding micro-monoliths