netimaaa · netimaaa · Jan 26, 2026
diff --git a/.gitignore b/.gitignore
@@ -1 +1,22 @@
-test
+# Python - app_python/
+app_python/__pycache__/
+app_python/*.py[cod]
+app_python/venv/
+app_python/env/
+app_python/*.log
+
+# Go - app_go/
+app_go/devops-info-service
+app_go/devops-info-service-*
+app_go/*.exe
+
+# IDE
+.idea/
+.vscode/
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Env
+.env
diff --git a/app_go/README.md b/app_go/README.md
@@ -0,0 +1,354 @@
+# DevOps Info Service (Go)
+
+A high-performance compiled implementation of the DevOps Info Service using Go's standard library. This version demonstrates the benefits of compiled languages for containerization and production deployments.
+
+## Overview
+
+This Go implementation provides the same functionality as the Python version but with:
+- **Faster startup time** - Compiled binary starts instantly
+- **Lower memory footprint** - Typically 10-20MB vs 50MB+ for Python
+- **Single binary deployment** - No runtime dependencies
+- **Better performance** - Native code execution
+- **Smaller container images** - Ideal for multi-stage Docker builds
+
+## Prerequisites
+
+- **Go**: 1.21 or higher
+- **No external dependencies** - Uses only Go standard library
+
+## Installation
+
+1. **Clone the repository** (if not already done):
+   ```bash
+   git clone <repository-url>
+   cd DevOps-Core-Course/app_go
+   ```
+
+2. **Initialize Go module** (already done):
+   ```bash
+   go mod init devops-info-service
+   ```
+
+3. **Verify installation**:
+   ```bash
+   go version
+   ```
+
+## Building the Application
+
+### Development Build
+
+Build for your current platform:
+
+```bash
+go build -o devops-info-service main.go
+```
+
+### Production Build
+
+Build with optimizations and reduced binary size:
+
+```bash
+# Standard build
+go build -ldflags="-s -w" -o devops-info-service main.go
+
+# Cross-compilation examples
+GOOS=linux GOARCH=amd64 go build -o devops-info-service-linux main.go
+GOOS=darwin GOARCH=arm64 go build -o devops-info-service-macos main.go
+GOOS=windows GOARCH=amd64 go build -o devops-info-service.exe main.go
+```
+
+**Build flags explained:**
+- `-ldflags="-s -w"` - Strip debug information and symbol table (smaller binary)
+- `GOOS` - Target operating system
+- `GOARCH` - Target architecture
+
+### Binary Size Comparison
+
+```bash
+# Check binary size
+ls -lh devops-info-service
+
+# Typical sizes:
+# - Standard build: ~6-8 MB
+# - Optimized build: ~4-5 MB
+# - Python equivalent: 50+ MB (with dependencies)
+```
+
+## Running the Application
+
+### Run Directly (Development)
+
+```bash
+# Run without building
+go run main.go
+
+# Run with custom configuration
+PORT=8080 go run main.go
+HOST=127.0.0.1 PORT=3000 go run main.go
+```
+
+### Run Compiled Binary
+
+```bash
+# Build first
+go build -o devops-info-service main.go
+
+# Run the binary
+./devops-info-service
+
+# Run with custom configuration
+PORT=8080 ./devops-info-service
+HOST=127.0.0.1 PORT=3000 ./devops-info-service
+```
+
+The service will be available at `http://localhost:8080` (default port for Go version)
+
+## API Endpoints
+
+### GET /
+
+Returns comprehensive service and system information.
+
+**Response Example:**
+```json
+{
+  "service": {
+    "name": "devops-info-service",
+    "version": "1.0.0",
+    "description": "DevOps course info service",
+    "framework": "Go net/http"
+  },
+  "system": {
+    "hostname": "my-laptop",
+    "platform": "darwin",
+    "platform_version": "go1.21.5",
+    "architecture": "arm64",
+    "cpu_count": 8,
+    "go_version": "go1.21.5"
+  },
+  "runtime": {
+    "uptime_seconds": 3600,
+    "uptime_human": "1 hours, 0 minutes",
+    "current_time": "2026-01-26T18:00:00.000000000Z",
+    "timezone": "UTC"
+  },
+  "request": {
+    "client_ip": "127.0.0.1:54321",
+    "user_agent": "curl/8.1.2",
+    "method": "GET",
+    "path": "/"
+  },
+  "endpoints": [
+    {
+      "path": "/",
+      "method": "GET",
+      "description": "Service information"
+    },
+    {
+      "path": "/health",
+      "method": "GET",
+      "description": "Health check"
+    }
+  ]
+}
+```
+
+**Testing:**
+```bash
+# Using curl
+curl http://localhost:8080/
+
+# Using curl with pretty print
+curl http://localhost:8080/ | jq
+
+# Using HTTPie
+http http://localhost:8080/
+```
+
+### GET /health
+
+Simple health check endpoint for monitoring.
+
+**Response Example:**
+```json
+{
+  "status": "healthy",
+  "timestamp": "2026-01-26T18:00:00.000000000Z",
+  "uptime_seconds": 3600
+}
+```
+
+**Testing:**
+```bash
+curl http://localhost:8080/health
+```
+
+## Configuration
+
+The application supports the following environment variables:
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `HOST` | `0.0.0.0` | Host address to bind to |
+| `PORT` | `8080` | Port number to listen on |
+
+**Example:**
+```bash
+export HOST=127.0.0.1
+export PORT=9000
+./devops-info-service
+```
+
+## Development
+
+### Project Structure
+
+```
+app_go/
+├── main.go                   # Main application
+├── go.mod                    # Go module definition
+├── README.md                 # This file
+└── docs/                     # Lab documentation
+    ├── LAB01.md             # Lab submission
+    ├── GO.md                # Language justification
+    └── screenshots/         # Proof of work
+```
+
+### Code Quality
+
+The Go implementation follows best practices:
+- **Standard library only** - No external dependencies
+- **Structured types** - Clear data models with JSON tags
+- **Error handling** - Proper error checking and logging
+- **HTTP standards** - Correct status codes and headers
+- **Clean code** - Well-organized functions and comments
+
+### Testing
+
+```bash
+# Run the application
+go run main.go
+
+# In another terminal, test endpoints
+curl http://localhost:8080/
+curl http://localhost:8080/health
+
+# Test error handling
+curl http://localhost:8080/nonexistent
+
+# Load testing
+ab -n 1000 -c 10 http://localhost:8080/health
+```
+
+### Performance Benchmarking
+
+```bash
+# Build optimized binary
+go build -ldflags="-s -w" -o devops-info-service main.go
+
+# Measure startup time
+time ./devops-info-service &
+sleep 1
+kill %1
+
+# Measure memory usage
+ps aux | grep devops-info-service
+
+# Benchmark requests
+ab -n 10000 -c 100 http://localhost:8080/health
+```
+
+## Advantages Over Python Version
+
+### 1. Performance
+- **Startup**: < 10ms vs ~1000ms for Python
+- **Memory**: ~15MB vs ~50MB for Python
+- **Response time**: Consistently faster due to native compilation
+
+### 2. Deployment
+- **Single binary**: No runtime or dependencies needed
+- **Cross-compilation**: Build for any platform from any platform
+- **Container size**: Much smaller Docker images (multi-stage builds)
+
+### 3. Production Readiness
+- **Stability**: Compiled code catches many errors at build time
+- **Concurrency**: Native goroutines for handling multiple requests
+- **Resource efficiency**: Lower CPU and memory usage
+
+### 4. DevOps Benefits
+- **Faster CI/CD**: Quick builds and tests
+- **Smaller artifacts**: Faster deployments
+- **Better scaling**: More instances per server
+
+## Comparison: Go vs Python
+
+| Aspect | Go | Python (FastAPI) |
+|--------|----|--------------------|
+| **Startup Time** | < 10ms | ~1000ms |
+| **Memory Usage** | ~15MB | ~50MB |
+| **Binary Size** | ~5MB | N/A (needs runtime) |
+| **Dependencies** | None | FastAPI, Uvicorn |
+| **Build Time** | ~1s | N/A (interpreted) |
+| **Container Size** | ~10MB | ~100MB+ |
+| **Performance** | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
+| **Development Speed** | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ |
+
+## Troubleshooting
+
+### Port Already in Use
+
+```bash
+# Find process using the port
+lsof -i :8080
+
+# Kill the process or use a different port
+PORT=9000 ./devops-info-service
+```
+
+### Build Errors
+
+```bash
+# Clean build cache
+go clean -cache
+
+# Verify Go installation
+go version
+
+# Check module
+go mod verify
+```
+
+### Cross-Compilation Issues
+
+```bash
+# List available platforms
+go tool dist list
+
+# Build for specific platform
+GOOS=linux GOARCH=amd64 go build main.go
+```
+
+## Future Enhancements
+
+This service will be enhanced in future labs:
+- **Lab 2**: Multi-stage Docker builds (Go excels here)
+- **Lab 3**: Unit tests with Go's testing package
+- **Lab 8**: Prometheus metrics endpoint
+- **Lab 9**: Kubernetes deployment
+- **Lab 12**: Persistent storage
+
+## Resources
+
+- [Go Documentation](https://golang.org/doc/)
+- [Go net/http Package](https://pkg.go.dev/net/http)
+- [Effective Go](https://golang.org/doc/effective_go)
+- [Go by Example](https://gobyexample.com/)
+
+## License
+
+This project is part of the DevOps Core Course.
+
+## Author
+
+Created for Lab 01 - DevOps Info Service: Web Application Development (Bonus Task)