quick start

git clone https://github.com/ronaudinho/wp
cd wp/cmd/wp-sqlite
go run main.go

scripts

• scripts under script directory are to be run from root directory e.g bash script/test.sh instead of cd script; bash test.sh
• docker build using script requires binary to built first, hence

1. bash script/build.sh
2. bash script/dockerize.sh

• running on docker not tried locally, some issue with my docker container network to host connection LOL but i would assume it works on machine where docker is properly set up

problem assessment

• probably emulating chat application
• chat would use websocket for sending as well most likely, so slight modification to the usual flow

structure

an attempt to follow

• Uncle Bob's Clean Architecture
• Domain Driven Design
• Hexagonal

├── cmd                       	# entrypoint to application, allow for different implementations
│   └── wp-sqlite				# in this case, using SQLite for persistence
│   │   ├── main.go
│       └── ...
├── internal
│   ├── service					# service layer is for business logic
│   │   ├── message.go
│   │   └── message_test.go
│   ├── model                	# model layer is for shared model
│   │   └── message.go
│   ├── repository				# repository layer is for data persistence
│   │   └── sqlite				# in this case, using SQLite 
│   │       ├── message.go
│   │       └── message_test.go
│   └── handler					# handler layer is for interfaces with external application
│       ├── rest              	# in this case, using REST
│       │   ├── message.go
│       │  	└── message_test.go
│       └── websocket			# in this case, using websocket 
│           ├── message.go
│           └── message_test.go
├── pkg                       	# globally shared package
│       └── validator			# validator to validate request body 
│           ├── validate.go
│           ├── validate_test.go
│           └── ...
└── ...

choice of tools

websocket/mqtt

• based on quick searching, mqtt is a layer above websocket, go mqtt library depends on go websockets library, hence using websocket in this exercise
• websocket looks simpler and easier to implement for now

persistence layer

• while usage of database is not required, getting all previously sent messages calls for some persistence layer. could have use cache but using embedded database instead

misc

interface placement

• declaring interface in the place where it is consumed, as per this talk

short, repeated naming

• only for short-lived variables

testing

• black box testing preferance
• should have done white box testing for one unexported function in pkg/validator but nvm