Computer Management API

A REST API for managing company computers built with Go, GORM, and PostgreSQL/SQLite. Integrates with Greenbone notification service.

Overview

This API allows system administrators to track company-issued computers, assign them to employees, and receive notifications via the Greenbone notification service when an employee has 3 or more computers assigned.

Architecture Diagram

Right now we are using the Mermaid diagram extensively to present the architecture, so thought this could be a nice touch

graph TB
    subgraph "Client Layer"
        CLI[curl/HTTP Client]
        API_CALLS[API Calls]
    end

    subgraph "HTTP Layer"
        ROUTER[Gorilla Mux Router]
        MIDDLEWARE[Middleware<br/>- Logging<br/>- CORS]
        HANDLERS[Computer Handler<br/>- CreateComputer<br/>- GetAllComputers<br/>- GetComputerByID<br/>- UpdateComputer<br/>- DeleteComputer<br/>- GetComputersByEmployee]
    end

    subgraph "Business Logic Layer"
        SERVICE[Computer Service<br/>- Validation<br/>- 3+ Computer Check<br/>- Business Rules]
    end

    subgraph "Data Layer"
        REPO[Computer Repository<br/>- CRUD Operations<br/>- Count Operations]
        DB[(Database<br/>SQLite/PostgreSQL)]
    end

    subgraph "External Services"
        NOTIFY_CLIENT[Notification Client<br/>- Retry Logic<br/>- Exponential Backoff]
        GREENBONE_SERVER[Greenbone Notification<br/>:8080/api/notify]
    end

    subgraph "Models"
        COMPUTER_MODEL[Computer Model<br/>- ID: uint<br/>- MACAddress: string*<br/>- ComputerName: string*<br/>- IPAddress: string*<br/>- EmployeeAbbreviation: *string<br/>- Description: string<br/>- CreatedAt/UpdatedAt]
    end

    CLI --> ROUTER
    API_CALLS --> ROUTER
    ROUTER --> MIDDLEWARE
    MIDDLEWARE --> HANDLERS
    HANDLERS --> SERVICE
    SERVICE --> REPO
    SERVICE --> NOTIFY_CLIENT
    REPO --> DB
    NOTIFY_CLIENT --> GREENBONE_SERVER

    SERVICE --> COMPUTER_MODEL
    REPO --> COMPUTER_MODEL
    HANDLERS --> COMPUTER_MODEL

    classDef clientLayer fill:#e1f5fe,stroke:#0288d1,color:#000;
    classDef httpLayer fill:#f3e5f5,stroke:#8e24aa,color:#000;
    classDef businessLayer fill:#e8f5e8,stroke:#43a047,color:#000;
    classDef dataLayer fill:#fff3e0,stroke:#fb8c00,color:#000;
    classDef externalLayer fill:#fce4ec,stroke:#d81b60,color:#000;
    classDef modelLayer fill:#f1f8e9,stroke:#7cb342,color:#000;

    class CLI,API_CALLS clientLayer
    class ROUTER,MIDDLEWARE,HANDLERS httpLayer
    class SERVICE businessLayer
    class REPO,DB dataLayer
    class NOTIFY_CLIENT,GREENBONE_SERVER externalLayer
    class COMPUTER_MODEL modelLayer

Quick Start

Docker Setup (Recommended)

# Clean up any existing containers
docker-compose down --volumes

# Start all services
docker-compose up --build

Local Development

# Clone and setup
git clone <repository-url>
cd computer-management-api
go mod tidy

# Set environment variables to point to Greenbone service
export NOTIFICATION_URL=http://localhost:8080
export PORT=8081
export DB_TYPE=sqlite
export DATABASE_URL=computers.db

# Run API (Greenbone service should be running on port 8080)
go run cmd/api/main.go

Greenbone Integration

This API works with exercise-admin-notification(https://github.com/greenbone/exercise-admin-notification) service:

docker pull greenbone/exercise-admin-notification
docker run -p 8080:8080 greenbone/exercise-admin-notification

API Endpoints

POST /api/computers - Create a new computer

GET /api/computers - Get all computers

GET /api/computers/{id} - Get computer by ID

PUT /api/computers/{id} - Update computer

DELETE /api/computers/{id} - Delete computer

GET /api/employees/{abbr}/computers - Get computers by employee

GET /api/health - Health check

How to use it

Create Computer

curl -X POST http://localhost:8081/api/computers \
  -H "Content-Type: application/json" \
  -d '{
    "mac_address": "00:11:22:33:44:55",
    "computer_name": "MacBook Pro 2023",
    "ip_address": "192.168.1.100",
    "employee_abbreviation": "mmu",
    "description": "Development laptop"
  }'

Test Notification

# Create 3 computers for employee "mmu" to trigger the notification
for i in {1..3}; do
  curl -X POST http://localhost:8081/api/computers \
    -H "Content-Type: application/json" \
    -d "{
      \"mac_address\": \"00:11:22:33:44:0$i\",
      \"computer_name\": \"Computer $i\",
      \"ip_address\": \"192.168.1.$i\",
      \"employee_abbreviation\": \"mmu\",
      \"description\": \"Test computer $i\"
    }"
  echo "Created computer $i"
  sleep 1
done

Notification System

When an employee is assigned 3+ computers, the system sends a notification to the notification service:

Format:

{
  "level": "warning",
  "employeeAbbreviation": "mmu",
  "message": "Employee mmu has been assigned 3 computers"
}

Configuration

Environment Variables

DB_TYPE - Database type (sqlite/postgres) sqlite

DATABASE_URL - Database connection string computers.db

NOTIFICATION_URL - Greenbone notification service URL http://localhost:8080

PORT - API server port 8081

Testing

# Run all tests
go test ./...

# Run with coverage
go test -cover ./...

# Test specific package
go test ./pkg/services/

Project Structure

├── cmd/
│   └── api/main.go          # Main API server
├── pkg/
│   ├── handlers/            # HTTP handlers
│   ├── services/            # Business logic
│   ├── models/              # Data models & repository
│   └── notifications/       # Notification client
├── internal/db/             # Database setup
├── docker-compose.yml       # Docker services
└── Dockerfile              # Container build

Next Implementation(or what is it missing)

Security

JWT auth middleware
Rate limiting
Validation on inputs

Database

Migration for schema changes
Connection pooling

Monitoring

Metrics
Alerts

DevOps

Docker container limits and health checks
CI/CD
local/dev/prod environment

Other

Pagination

Jetlum/computer-management-api