Users Service

A RESTful API service for managing users, built with Go and PostgreSQL. This service provides endpoints for creating, reading, updating, and deleting users. It also includes Swagger documentation for easy API exploration and testing.

---

Description

The Users Service is designed to manage user data efficiently. It leverages:

• Go: A high-performance backend framework.
• PostgreSQL: A robust relational database for storing user data.
• Docker Compose: Simplifies containerized deployment of the application and database.
• Swagger: Provides interactive API documentation.

---

File Structure

users-service/
├── cmd/
│   └── server/
│       └── main.go                 # Main entry point of the application
├── docs/                           # Swagger documentation (auto-generated)
│   ├── docs.go
│   ├── swagger.json
│   └── swagger.yaml
├── internal/
│   ├── controller/
│   │   ├── user_controller.go      # Handles HTTP requests for user operations
│   │   └── user_controller_test.go # Unit tests for user_controller.go
│   ├── model/
│   │   └── user.go                 # Defines the User model
│   ├── repository/
│   │   ├── user_repository.go      # Interacts with the database
│   │   └── user_repository_test.go # Unit tests for user_repository.go
│   ├── service/
│       ├── user_service.go         # Business logic for user operations
│       └── user_service_test.go    # Unit tests for user_service.go
├── pkg/
│   └── database/
│       └── postgres.go             # Database connection and schema setup
├── generate_users.sh               # Script to generate a JSON file of test users
├── post-request-users.sh           # Script to bulk insert users into the database via API
├── docker-compose.yml              # Docker Compose configuration for app and PostgreSQL
├── Dockerfile                      # Dockerfile to build the Go application
├── go.mod                          # Go module dependencies
├── go.sum                          # Go module checksums
└── README.md                       # Project documentation (this file)

---

How to Build and Run

1. Prerequisites

• Docker and Docker Compose installed on your system.
• jq installed (used in post-request-users.sh).

2. Build and Run with Docker Compose

To build and run the service:

docker compose up --build -d

This will:

1. Build the Go application.
2. Start the application container (app) on port 8080.
3. Start a PostgreSQL container (postgres) on port 5432.

3. Verify the Service

Check if the service is running:

curl http://localhost:8080/users

---

How to Use

1. Generate Test Users

Run the generate_users.sh script to create a file called users.json with 100 test users:

./generate_users.sh

2. Insert Users into the Database

Use the post-request-users.sh script to bulk insert the generated users into the database via the API:

./post-request-users.sh

3. Access Swagger Docs

Swagger UI is available at:

http://localhost:8080/swagger/index.html

You can explore all API endpoints, view request/response schemas, and test the API directly from your browser.

---

API Endpoints

Method	Endpoint	Description
GET	/users	List all users
POST	/users	Create a new user
PUT	/users/{id}	Update an existing user
DELETE	/users/{id}	Delete a user

---

Environment Variables

The following environment variables are used in docker-compose.yml:

Variable	Default Value	Description
DB_HOST	postgres	Database host
DB_PORT	5432	Database port
DB_USER	postgres	Database username
DB_PASSWORD	postgres	Database password
DB_NAME	users_db	Database name

---

Development Notes

Running Locally Without Docker

If you want to run the service locally without Docker:

1. Start a PostgreSQL server locally.
2. Set environment variables (DB_HOST, etc.).
3. Run the Go application:

   go run cmd/server/main.go

Running Tests

Run unit tests for all components:

go test ./... -v