Hexagonal Architecture in Golang

This application implements a Golang backend using Hexagonal Architecture which aims to decouple the components of the domain/application from the frameworks like http server, storage and others.

To demonstrate this, this application implements a simple URL Shortener which makes use of different adapters. The application can be executed from command-line, or as a service (HTTP and gRPC).

Goals

• Implement some service using the principles of the Hexagonal Architecture.
• Use more than one framework for the same function, to demonstrante how the ports and adapters works in practice.
• Create a project template.

Storage adapters:

• MongoDB
• Redis

Serializer adapters:

• JSON
• MessagePack

Communication adapters:

• Gin http server
• Chi http server
• gRPC

Steps to run the cli application

The application needs an instance of Redis or MongoDB running. Just check the cmd/cli/main.go or cmd/http/main.go and adjust the connection string for your servers.

$ go run cmd/cli/main.go

You would get an output like the following:

Generating Code from URL: http://www.google.com
{"code":"LWK9v1Qng","url":"http://www.google.com","created_at":1650829428}

Retrieve the URL from code: LWK9v1Qng
{"code":"LWK9v1Qng","url":"http://www.google.com","created_at":1650829428}

Steps to run the service application

$ go run cmd/http/main.go

You would get an output like the following:

CHI  listening on :8000
GIN  listening on :9000
GRPC listening on :7000

From now, you can perform HTTP requests on http://localhost:8000 and http://localhost:9000

HTTP: Get Url (or redirect if call from browser)

Method GET
Endpoint: <hostname:port>/:code

Code is the short code generated from a given URL.

HTTP: Generate Shortcode

Method POST
Endpoint: <hostname:port>/

Payload:

{
    "url": "http://www.google.com"
}

Example using curl:

curl --request POST 'localhost:9000/' \
--header 'Content-Type: application/json' \
--data '{"url": "http://www.google.com.br"}'

Expected output

{"code":"AS4YOJQ7R","url":"http://www.google.com.br","created_at":1650830243}

gRPC

The code show how to use evans in interactive mode to perform gRPC call.

cd adapter/grpc/proto 
evans --host localhost --port 7000 --proto shortener_msg.proto,shortener_service.proto

TO-DO

• Add adapter for Jwt and Paseto tokens