trying embedded caddy reverse proxy

proxy/README.md

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+# Netbird Reverse Proxy
+
+A lightweight, configurable reverse proxy server with graceful shutdown support.
+
+## Features
+
+- Simple reverse proxy with customizable headers
+- Configuration via environment variables or JSON file
+- Graceful shutdown with configurable timeout
+- Structured logging with logrus
+- Configurable timeouts (read, write, idle)
+- Health monitoring support
+
+## Building
+
+```bash
+# Build the binary
+GOWORK=off go build -o bin/proxy ./cmd/proxy
+
+# Or use make if available
+make build
+```
+
+## Configuration
+
+The proxy can be configured using either environment variables or a JSON configuration file. Environment variables take precedence over file-based configuration.
+
+### Environment Variables
+
+| Variable | Description | Default |
+|----------|-------------|---------|
+| `NB_PROXY_LISTEN_ADDRESS` | Address to listen on | `:8080` |
+| `NB_PROXY_TARGET_URL` | Target URL to proxy requests to | **(required)** |
+| `NB_PROXY_READ_TIMEOUT` | Read timeout duration | `30s` |
+| `NB_PROXY_WRITE_TIMEOUT` | Write timeout duration | `30s` |
+| `NB_PROXY_IDLE_TIMEOUT` | Idle timeout duration | `60s` |
+| `NB_PROXY_SHUTDOWN_TIMEOUT` | Graceful shutdown timeout | `10s` |
+| `NB_PROXY_LOG_LEVEL` | Log level (debug, info, warn, error) | `info` |
+
+### Configuration File
+
+Create a JSON configuration file:
+
+```json
+{
+  "listen_address": ":8080",
+  "target_url": "http://localhost:3000",
+  "read_timeout": "30s",
+  "write_timeout": "30s",
+  "idle_timeout": "60s",
+  "shutdown_timeout": "10s",
+  "log_level": "info"
+}
+```
+
+## Usage
+
+### Using Environment Variables
+
+```bash
+export NB_PROXY_TARGET_URL=http://localhost:3000
+export NB_PROXY_LOG_LEVEL=debug
+./bin/proxy
+```
+
+### Using Configuration File
+
+```bash
+./bin/proxy -config config.json
+```
+
+### Combining Both
+
+Environment variables override file configuration:
+
+```bash
+export NB_PROXY_LOG_LEVEL=debug
+./bin/proxy -config config.json
+```
+
+### Docker Example
+
+```bash
+docker run -e NB_PROXY_TARGET_URL=http://backend:3000 \
+           -e NB_PROXY_LISTEN_ADDRESS=:8080 \
+           -p 8080:8080 \
+           netbird-proxy
+```
+
+## Architecture
+
+The application follows a clean architecture with clear separation of concerns:
+
+```
+proxy/
+├── cmd/
+│   └── proxy/
+│       └── main.go          # Entry point, CLI handling, signal management
+├── config.go                # Configuration loading and validation
+├── server.go                # Server lifecycle (Start/Stop)
+├── go.mod                   # Module dependencies
+└── README.md
+```
+
+### Key Components
+
+- **config.go**: Handles configuration loading from environment variables and files using the `github.com/caarlos0/env/v11` library
+- **server.go**: Encapsulates the HTTP server and reverse proxy logic with proper lifecycle management
+- **cmd/proxy/main.go**: Entry point that orchestrates startup, graceful shutdown, and signal handling
+
+## Graceful Shutdown
+
+The server handles SIGINT and SIGTERM signals for graceful shutdown:
+
+1. Signal received (Ctrl+C or kill command)
+2. Server stops accepting new connections
+3. Existing connections are allowed to complete within the shutdown timeout
+4. Server exits cleanly
+
+Press `Ctrl+C` to trigger graceful shutdown:
+
+```bash
+^C2026-01-13 22:40:00 INFO Received signal: interrupt
+2026-01-13 22:40:00 INFO Shutting down server gracefully...
+2026-01-13 22:40:00 INFO Server stopped successfully
+2026-01-13 22:40:00 INFO Server exited successfully
+```
+
+## Headers
+
+The proxy automatically sets the following headers on proxied requests:
+
+- `X-Forwarded-Host`: Original request host
+- `X-Origin-Host`: Target backend host
+- `X-Real-IP`: Client's remote address
+
+## Error Handling
+
+- Invalid backend connections return `502 Bad Gateway`
+- All proxy errors are logged with details
+- Configuration errors are reported at startup
+
+## Development
+
+### Prerequisites
+
+- Go 1.25 or higher
+- Access to `github.com/sirupsen/logrus`
+- Access to `github.com/caarlos0/env/v11`
+
+### Testing Locally
+
+Start a test backend:
+
+```bash
+# Terminal 1: Start a simple backend
+python3 -m http.server 3000
+```
+
+Start the proxy:
+
+```bash
+# Terminal 2: Start the proxy
+export NB_PROXY_TARGET_URL=http://localhost:3000
+./bin/proxy
+```
+
+Test the proxy:
+
+```bash
+# Terminal 3: Make requests
+curl http://localhost:8080
+```
+
+## License
+
+Part of the Netbird project.