Golang microservices - API Gateway

Stack

• Go 1.18
• Docker
• Docker Compose
• Pattern: API Gateway

Important

Docker, docker-compose, curl should be preinstalled to deploy and test application. Used Docker version 20.10.17 and docker-compose version 1.29.0.

Microservices entities

• Authenticator-Microservice
• User-Microservice
• Proxy-Microservice

Architecture

Authenticator-Microservice

Authenticator-Microservice authenticates client HTTP request if the request is valid or not by analyzing the value in the user request header Username. If the user with this header is present in the database, then it's a valid request otherwise the user request is not a valid request.

Implement API named /auth which will perform the above task. For every authenticated user request, it sends HTTP code 200 to the Proxy-Microservice and for every unauthenticated request, it sends HTTP status code 401 unauthorized

User-Microservice

Implements:

1. API: /user/profile Method: GET, Secured: true This API will return the username, dob (date of birth), age, email, and phone number.

Example

{
    "UserProfile": {
        "username": "Uncle Bob",
        "date_of_birth": "05-12-1952",
        "age": 69,
        "e-mail": "[email protected]",
        "phone_number": "760-474-1420"
    }
}

2. API: /microservice/name Method: GET , Secured: false This API will return the name of microservice (for our use case user-microservice ).

Example

{
    "MicroserviceName": "user-microservice"
}

Proxy-Microservice

The Proxy-Microservice is the contact point for the client. It does conditional routing based on these services: User-Microservice, Authenticator-Microservice.

1. If authentication is required for the request API, it routes it to Authenticator-Microservice and if the authenticator microservice returns status code 200, it then routes to User-Microservice otherwise it sends the request back to the user as the user request is unauthorized.

2. If the authentication is not required, then it routes directly to User-Microservice.

Configuration

1. Authenticator-Microservice - HTTP-port listening 8081 by default. You can change cofiguration params in config file config/envs/app.env. All testing data saved in directory data.

2. User-Microservice - HTTP-port listening 8082 by default. You can change cofiguration params in config file config/envs/app.env. All testing data saved in directory data.

3. Proxy-Microservice - HTTP-port listening 8888 by default. You can change cofiguration params in config file config/envs/app.env.

How to deploy

Deploy application:

docker-compose up --build 

It will run Authenticator-Microservice, User-Microservice, Proxy-Microservice. You can access to the app via Proxy-Microservice:

http://127.0.0.1:8888/user/profile

http://127.0.0.1:8888/microservice/name

Stop application:

docker-compose down

Testing

Makefile

Makefile - contains curl commands to send.

make test - send GET requests to retrieve data.

Example:

$ make test

Demo Data

All demo data is included in the application code (hardcoded).

The data for the User-Service service is located in the directory go-user-service/data/users.go.

var Users = map[string]models.User{
	"Uncle Bob": {
		Username:    "Uncle Bob",
		DateOfBirth: "05-12-1952",
		Age:         69,
		Email:       "[email protected]",
		PhoneNumber: "760-474-1420",
	},
	"Gopher": {
		Username:    "Gopher",
		DateOfBirth: "10-11-2009",
		Age:         13,
		Email:       "[email protected]",
		PhoneNumber: "304-786-2880",
	},
	"Deve": {
		Username:    "Deve",
		DateOfBirth: "29-04-2003",
		Age:         19,
		Email:       "[email protected]",
		PhoneNumber: "304-786-2880",
	},
	"Steve": {
		Username:    "Steve",
		DateOfBirth: "29-04-2000",
		Age:         22,
		Email:       "[email protected]",
		PhoneNumber: "304-786-2880",
	},
	"Molly": {
		Username:    "Molly",
		DateOfBirth: "29-04-1992",
		Age:         30,
		Email:       "[email protected]",
		PhoneNumber: "304-786-2880",
	},
}

The data for the Auth-Service service is located in the directory go-auth-service/data/users.go.

var Users = map[string]models.User{
	"Uncle Bob": {
		Username:   "Uncle Bob",
		AuthStatus: true,
	},
	"Gopher": {
		Username:   "Gopher",
		AuthStatus: true,
	},
	"Deve": {
		Username:   "Deve",
		AuthStatus: false,
	},
	"Steve": {
		Username:   "Steve",
		AuthStatus: true,
	},
	"Molly": {
		Username:   "Molly",
		AuthStatus: false,
	},
}