haproxy-mcp/CLAUDE.md

# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

HAProxy Dynamic Load Balancer Management Suite - a system for runtime management of HAProxy without restarts. Provides MCP interface for dynamic domain/server management with HTTP, HTTPS, and HTTP/3 (QUIC) support.

**Key Feature:** Zero-reload domain management using HAProxy map files and pool backends.

## Architecture

```
┌──────────────────────────────────────────────────┐
│ HAProxy (host network)                           │
│ TCP 80/443 (HTTP/1.1, HTTP/2) + UDP 443 (HTTP/3) │
│ Runtime API: localhost:9999                      │
│ MCP Proxy: mcp.inouter.com → localhost:8000      │
└──────────────┬───────────────────────────────────┘
               │
         ┌─────▼─────┐
         │ MCP       │
         │ Server    │
         │ :8000     │
         └───────────┘
```

### Domain Routing Flow
```
Request → HAProxy Frontend
    ↓
domains.map lookup (Host header)
    ↓
pool_N backend (N = 1-100)
    ↓
Server (from servers.json, auto-restored on startup)
```

## Services

### HAProxy (Podman Quadlet)
```bash
systemctl start haproxy      # Start
systemctl stop haproxy       # Stop
systemctl restart haproxy    # Restart
systemctl status haproxy     # Status
```
- Quadlet config: `/etc/containers/systemd/haproxy.container`
- Network mode: `host` (direct access to host services)

### MCP Server (systemd)
```bash
systemctl start haproxy-mcp     # Start
systemctl stop haproxy-mcp      # Stop
systemctl restart haproxy-mcp   # Restart
journalctl -u haproxy-mcp -f    # Logs
```
- Transport: `streamable-http`
- Internal: `http://localhost:8000/mcp`
- External: `https://mcp.inouter.com/mcp` (via HAProxy)
- **Auto-restore:** Servers restored from `servers.json` on startup

## Zero-Reload Domain Management

### How It Works
1. **domains.map**: Maps domain → pool backend (e.g., `example.com pool_1`)
2. **Pool backends**: 100 pre-configured backends (`pool_1` to `pool_100`)
3. **Runtime API**: Add/remove map entries and configure servers without reload
4. **servers.json**: Persistent server configuration, auto-restored on MCP startup

### Adding a Domain

**Default (HTTP/HTTPS/H3):**
```bash
haproxy_add_domain("example.com", "10.0.0.1")
# Creates: pool_N_1 (80), pool_N_ssl_1 (443), pool_N_h3_1 (443)
```

**Custom port (HTTP only):**
```bash
haproxy_add_domain("api.example.com", "10.0.0.1", 8080)
# Creates: pool_N_1 (8080) only
```

This will:
1. Find available pool (e.g., `pool_5`)
2. Add to `domains.map`: `example.com pool_5`
3. Update HAProxy runtime map: `add map ... example.com pool_5`
4. Configure server(s) in pool via Runtime API
5. Save to `servers.json` for persistence

**No HAProxy reload required!**

### Port Logic
| Setting | Servers Created |
|---------|-----------------|
| Default (80/443) | HTTP + HTTPS + HTTP/3 (3 servers) |
| Custom port | HTTP only (1 server) |

### Files
| File | Purpose |
|------|---------|
| `domains.map` | Domain → Pool mapping |
| `servers.json` | Server IP/port persistence |
| `haproxy.cfg` | Pool backend definitions (static) |

## SSL/TLS Certificates

### Current Setup
| Item | Value |
|------|-------|
| ACME Client | certbot + dns-cloudflare |
| Cert Directory | `/opt/haproxy/certs/` (auto-loaded by HAProxy) |
| Deploy Hook | `/etc/letsencrypt/renewal-hooks/deploy/haproxy-deploy.sh` |

### How It Works
1. HAProxy binds with `crt /etc/haproxy/certs/` (directory, not file)
2. All `.pem` files in directory are auto-loaded
3. SNI selects correct certificate based on domain
4. Certbot deploy hook auto-creates combined PEM on issue/renewal

### Adding New Certificate
```bash
# Issue certificate (Let's Encrypt)
certbot certonly \
  --dns-cloudflare \
  --dns-cloudflare-credentials ~/.secrets/cloudflare.ini \
  -d "newdomain.com" -d "*.newdomain.com"
```

Deploy hook automatically:
1. Combines `fullchain.pem + privkey.pem` → `/opt/haproxy/certs/newdomain.com.pem`
2. Restarts HAProxy
3. **No manual cfg modification needed!**

### Google Trust Services (optional)
```bash
certbot certonly \
  --server https://dv.acme-v02.api.pki.goog/directory \
  --eab-kid "KEY_ID" \
  --eab-hmac-key "HMAC_KEY" \
  --dns-cloudflare \
  --dns-cloudflare-credentials ~/.secrets/cloudflare.ini \
  -d "domain.com" -d "*.domain.com"
```

### Certificate Commands
```bash
# List certificates
certbot certificates

# Renew all (dry run)
certbot renew --dry-run

# Renew all (force)
certbot renew --force-renewal

# Check loaded certs in HAProxy
ls -la /opt/haproxy/certs/
```

### Cloudflare Credentials
- File: `~/.secrets/cloudflare.ini`
- Format: `dns_cloudflare_api_token = TOKEN`

## HTTP/3 (QUIC)

Frontend supports all protocols:
```
TCP 443: HTTP/1.1, HTTP/2
UDP 443: HTTP/3 (QUIC)
```

Clients receive `alt-svc: h3=":443"; ma=86400` header for HTTP/3 upgrade.

## MCP Security

HAProxy proxies MCP with Bearer Token authentication (configured in frontend ACL).

### Access Rules
| Source | Token Required |
|--------|----------------|
| Tailscale (100.64.0.0/10) | No |
| External (CF Worker, etc.) | Yes |

### Token Location
- File: `/opt/haproxy/conf/mcp-token.env`

### Connection Examples

**Tailscale (no auth):**
```bash
claude mcp add --transport http haproxy http://100.108.39.107:8000/mcp
```

**External (with auth):**
```bash
curl -X POST https://mcp.inouter.com/mcp \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}},"id":0}'
```

## MCP Tools (17 total)

### Domain Management
| Tool | Description |
|------|-------------|
| `haproxy_list_domains` | List all domains with pool mappings and servers |
| `haproxy_add_domain` | Add domain to available pool (no reload) |
| `haproxy_remove_domain` | Remove domain from pool (no reload) |

### Server Management
| Tool | Description |
|------|-------------|
| `haproxy_list_servers` | List servers for a domain |
| `haproxy_add_server` | Add server to slot (1-10), auto-saved |
| `haproxy_remove_server` | Remove server from slot, auto-saved |
| `haproxy_set_server_state` | Set state: ready/drain/maint |
| `haproxy_set_server_weight` | Set weight (0-256) |
| `haproxy_get_server_health` | Get UP/DOWN/MAINT status |

### Monitoring
| Tool | Description |
|------|-------------|
| `haproxy_stats` | HAProxy statistics |
| `haproxy_backends` | List backends |
| `haproxy_list_frontends` | List frontends with status |
| `haproxy_get_connections` | Active connections per server |

### Configuration
| Tool | Description |
|------|-------------|
| `haproxy_reload` | Validate and reload config |
| `haproxy_check_config` | Validate config syntax |
| `haproxy_save_state` | Save server state to disk (legacy) |
| `haproxy_restore_state` | Restore state from disk (legacy) |

## Key Conventions

### Pool-Based Routing
- Domains map to pools: `example.com` → `pool_N`
- 100 pools available: `pool_1` to `pool_100`
- Each pool has 10 server slots

### Server Naming
Pool backends use this naming:
- `pool_N_1` to `pool_N_10` - HTTP (always created)
- `pool_N_ssl_1` to `pool_N_ssl_10` - HTTPS (default ports only)
- `pool_N_h3_1` to `pool_N_h3_10` - HTTP/3 QUIC (default ports only)

**Examples:**
```
example.com (80/443 default):
  └─ pool_5_1, pool_5_ssl_1, pool_5_h3_1

api.example.com (custom port 8080):
  └─ pool_6_1 only
```

### Persistence
- **domains.map**: Survives HAProxy restart
- **servers.json**: Auto-restored by MCP on startup
- No manual save required - `haproxy_add_server` auto-saves

## HAProxy Runtime API

```bash
# Show domain mappings
echo "show map /usr/local/etc/haproxy/domains.map" | nc localhost 9999

# Add domain mapping (runtime only)
echo "add map /usr/local/etc/haproxy/domains.map example.com pool_5" | nc localhost 9999

# Show server state
echo "show servers state" | nc localhost 9999

# Show backends
echo "show backend" | nc localhost 9999

# Set server address
echo "set server pool_1/pool_1_1 addr 10.0.0.1 port 80" | nc localhost 9999

# Enable server
echo "set server pool_1/pool_1_1 state ready" | nc localhost 9999
```

## Directory Structure

```
/opt/haproxy/
├── mcp/                 # MCP server (streamable-http)
│   └── server.py        # Main MCP server (~1100 lines, 17 tools)
├── conf/
│   ├── haproxy.cfg      # Main HAProxy config (100 pool backends)
│   ├── domains.map      # Domain → Pool mapping
│   ├── servers.json     # Server persistence (auto-managed)
│   └── mcp-token.env    # Bearer token for MCP auth
├── certs/               # SSL/TLS certificates (HAProxy PEM format)
├── data/                # Legacy state files
├── scripts/             # Utility scripts
└── run/                 # Runtime socket files

/etc/letsencrypt/
├── live/                # Certbot certificates
└── renewal-hooks/deploy/
    └── haproxy-deploy.sh  # Auto-combine PEM & restart HAProxy

/etc/containers/systemd/
└── haproxy.container    # Podman Quadlet config
```

## Configuration Files

| File | Purpose |
|------|---------|
| `/opt/haproxy/conf/haproxy.cfg` | HAProxy main config |
| `/opt/haproxy/conf/domains.map` | Domain routing map |
| `/opt/haproxy/conf/servers.json` | Server persistence |
| `/opt/haproxy/certs/*.pem` | SSL certificates (auto-loaded) |
| `/etc/containers/systemd/haproxy.container` | Podman Quadlet |
| `/etc/systemd/system/haproxy-mcp.service` | MCP service |
| `/opt/haproxy/conf/mcp-token.env` | MCP auth token |
| `/etc/letsencrypt/renewal-hooks/deploy/haproxy-deploy.sh` | Cert deploy hook |
| `~/.secrets/cloudflare.ini` | Cloudflare API token |

## Startup Sequence

```
1. systemd starts haproxy.service
   ↓
2. HAProxy loads haproxy.cfg (100 pool backends)
   ↓
3. HAProxy loads domains.map (domain → pool mapping)
   ↓
4. systemd starts haproxy-mcp.service
   ↓
5. MCP server reads servers.json
   ↓
6. MCP server restores servers via Runtime API
   ↓
7. Ready to serve traffic
```