Go project structures

source & credit : thank you Kat Zień
video
repository

Goals

• Consistent เพื่อให้โครงสร้างทุกส่วนของไปในทิศทางเดียวกัน
• Easy to understand
• Easy to change, loosely-coupled แก้ไขง่าย โดยไม่กระทบส่วนอื่น ๆ
• East to test
• Structure reflects the design exactly

Example

Beer reviewing service

Requirements

1. Users can add a beer
2. Users can add a review for a beer
3. Users can list all beers
4. Users can list all reviews for a selected beer.
5. Option to store data either in memory or JSON file
6. Ability to add some sample data

Flat structure

📦/
┣ 📜data.go
┣ 📜handlers.go
┣ 📜main.go
┣ 📜model.go
┣ 📜storage.go
┣ 📜storage_json.go
┣ 📜storage_mem.go
┗ 📜[file name]_test.go

main.go

• Get storage [Requirement 5]
• Call for routes to get service
• Mock data [Requirement 6]
• HTTP server listener

handlers.go

• Manage with request (header, body, params,etc...)
• Call data from storage

model.go

• Entities struct

---

Group by function (Layered archetecture)

• presentation / ui
• business logic
• external deps / infrastructure

📦/
┣ 📜data.go
┣ 📂handlers
┃ ┣ 📜beers.go
┃ ┗ 📜reviews.go
┣ 📂models
┃ ┣ 📜beer.go
┃ ┣ 📜review.go
┃ ┗ 📜storage.go
┗ 📂storage
┣ 📜json.go
┗ 📜memory.go

main.go

• Call for routes to get service

handlers

• request / response manage
• get storage

storage

• database services
  • struct
  • methods [ CRUD ]

Cons

เสี่ยงต่อการเกิด Circular dependencies สูง เช่น layer models ต้องถูกใช้งานจากทั้ง layer บน และ ล่าง

---

Group by module

📦/
┣ 📜main.go
┣ 📂beers
┃ ┣ 📜beer.go
┃ ┗ 📜handler.go
┣ 📂reviews
┃ ┣ 📜review.go
┃ ┣ 📜handler.go
┗ 📂storage
┣ 📜json.go
┣ 📜data.go
┣ 📜memory.go
┗ 📜storage.go

Cons

เสี่ยงต่อการเกิด Circular dependencies เนื่องจาก ข้อมูลมีการเชื่อมโยงกัน [Requirement 2, 4]

• Beer ก็ใช้งาน Review
• Review ก็ใช้งาน Beer

---

Group by context

Domain Driven Design

• Estalish your domain and business logic
• Define your bounded contexts, the models within each context and the ubiquitous language
• Catagorising the building blocks of your system

Building blocks

• Context beer tasting
• Language beer, review, storage
• Entities Beer, Review
• Value Objects Brewery, Author
• Aggregate Beer Reviewer
• Service Beer adder / adding, Beer lister / listing, Review lister
• Events Beer added, Review added, Beer already exists, Beer not found
• Repository Beer repository, Review repository

📦/
┣ 📂adding
┃ ┣ 📜endpoint.go
┃ ┗ 📜service.go
┣ 📂beers
┃ ┣ 📜beer.go
┃ ┗ 📜sample_beers.go
┣ 📂listing
┃ ┣ 📜endpoint.go
┃ ┗ 📜service.go
┣ 📂reviewing
┃ ┣ 📜endpoint.go
┃ ┗ 📜service.go
┣ 📂reviews
┃ ┣ 📜review.go
┃ ┗ 📜sample_reviews.go
┣ 📂storage
┃ ┣ 📜json.go
┃ ┣ 📜type.go
┃ ┗ 📜memory.go
┗ 📜main.go

---

Hexagonal Architecture

📦/
┣ 📂cmd
┃ ┣ 📂beer-server
┃ ┃ ┗ 📜main.go
┃ ┗ 📂sample-data
┃ ┗ 📜main.go
┗ 📂pkg
┣ 📂adding
┃ ┣ 📜endpoint.go
┃ ┗ 📜service.go
┣ 📂beers
┃ ┗ 📜beer.go
┣ 📂listing
┃ ┣ 📜endpoint.go
┃ ┗ 📜service.go
┣ 📂reviewing
┃ ┣ 📜endpoint.go
┃ ┗ 📜service.go
┣ 📂reviews
┃ ┗ 📜review.go
┣ 📂storage
┃ ┣ 📜json.go
┃ ┣ 📜type.go
┃ ┗ 📜memory.go
┣ 📂http
┃ ┣ 📂rest
┃ ┃ ┗ 📜handler.go
┃ ┣ 📂soap
┃ ┗ 📂rpc
┣ 📂resources
┃ ┗ 📂sample-data
┃ ┣ 📜sample_beers.go
┃ ┗ 📜sample_reviews.go

cmd

• commands to use service
  • use by request http protocal
  • use by using command line

resources/sample-data

• seperate sample data to individual folder