feat: add pprof for debuging

README.md

@@ -14,6 +14,54 @@ A lightweight SSH-based tunnel server written in Go that enables secure TCP and
 - Go 1.18 or higher
 - Valid domain name for subdomain routing
 
+## Environment Variables
+
+The following environment variables can be configured in the `.env` file:
+
+| Variable | Description | Default | Required |
+|----------|-------------|---------|----------|
+| `DOMAIN` | Domain name for subdomain routing | `localhost` | No |
+| `PORT` | SSH server port | `2200` | No |
+| `TLS_ENABLED` | Enable TLS/HTTPS | `false` | No |
+| `TLS_REDIRECT` | Redirect HTTP to HTTPS | `false` | No |
+| `CERT_LOC` | Path to TLS certificate | `certs/cert.pem` | No |
+| `KEY_LOC` | Path to TLS private key | `certs/privkey.pem` | No |
+| `SSH_PRIVATE_KEY` | Path to SSH private key (auto-generated if missing) | `certs/id_rsa` | No |
+| `CORS_LIST` | Comma-separated list of allowed CORS origins | - | No |
+| `ALLOWED_PORTS` | Port range for TCP tunnels (e.g., 40000-41000) | `40000-41000` | No |
+| `PPROF_ENABLED` | Enable pprof profiling server | `false` | No |
+| `PPROF_PORT` | Port for pprof server | `6060` | No |
+
+**Note:** All environment variables now use UPPERCASE naming. The application includes sensible defaults for all variables, so you can run it without a `.env` file for basic functionality.
+
+### SSH Key Auto-Generation
+
+If the SSH private key specified in `SSH_PRIVATE_KEY` doesn't exist, the application will automatically generate a new 4096-bit RSA key pair at the specified location. This makes it easier to get started without manually creating SSH keys.
+
+### Profiling with pprof
+
+To enable profiling for performance analysis:
+
+1. Set `PPROF_ENABLED=true` in your `.env` file
+2. Optionally set `PPROF_PORT` to your desired port (default: 6060)
+3. Access profiling data at `http://localhost:6060/debug/pprof/`
+
+Common pprof endpoints:
+- `/debug/pprof/` - Index page with available profiles
+- `/debug/pprof/heap` - Memory allocation profile
+- `/debug/pprof/goroutine` - Stack traces of all current goroutines
+- `/debug/pprof/profile` - CPU profile (30-second sample by default)
+- `/debug/pprof/trace` - Execution trace
+
+Example usage with `go tool pprof`:
+```bash
+# Analyze CPU profile
+go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30
+
+# Analyze memory heap
+go tool pprof http://localhost:6060/debug/pprof/heap
+```
+
 ## Contributing
 Contributions are welcome!