haproxy-mcp/haproxy_mcp/tools/health.py

"""Health check tools for HAProxy MCP Server."""

import json
import os
import subprocess
import time
from typing import Annotated, Any

from pydantic import Field

from ..config import (
    MAP_FILE,
    SERVERS_FILE,
    HAPROXY_CONTAINER,
    StateField,
    STATE_MIN_COLUMNS,
)
from ..exceptions import HaproxyError
from ..validation import validate_domain, validate_backend_name
from ..haproxy_client import haproxy_cmd
from ..file_ops import get_backend_and_prefix
from ..utils import parse_stat_csv


def register_health_tools(mcp):
    """Register health check tools with MCP server."""

    @mcp.tool()
    def haproxy_health() -> str:
        """Check overall system health (MCP server, HAProxy, config files).

        Use this for monitoring integration. Returns "healthy" if all components are OK.

        Returns:
            JSON with:
            - status: "healthy" or "unhealthy"
            - components.mcp: MCP server status
            - components.haproxy: HAProxy connectivity, version, uptime
            - components.config_files: map_file and servers_file accessibility

        Example:
            # Returns: {"status": "healthy", "components": {"mcp": {"status": "ok"}, ...}}
        """
        result: dict[str, Any] = {
            "status": "healthy",
            "timestamp": time.time(),
            "components": {
                "mcp": {"status": "ok"},
                "haproxy": {"status": "unknown"},
                "config_files": {"status": "unknown"}
            }
        }

        # Check HAProxy connectivity
        try:
            info = haproxy_cmd("show info")
            for line in info.split("\n"):
                if line.startswith("Version:"):
                    result["components"]["haproxy"]["version"] = line.split(":", 1)[1].strip()
                elif line.startswith("Uptime_sec:"):
                    result["components"]["haproxy"]["uptime_sec"] = int(line.split(":", 1)[1].strip())
            result["components"]["haproxy"]["status"] = "ok"
        except HaproxyError as e:
            result["components"]["haproxy"]["status"] = "error"
            result["components"]["haproxy"]["error"] = str(e)
            result["status"] = "degraded"

        # Check container status
        try:
            container_result = subprocess.run(
                ["podman", "inspect", "--format", "{{.State.Status}}", HAPROXY_CONTAINER],
                capture_output=True, text=True, timeout=5
            )
            if container_result.returncode == 0:
                container_status = container_result.stdout.strip()
                result["components"]["container"] = {
                    "status": "ok" if container_status == "running" else container_status,
                    "state": container_status
                }
            else:
                result["components"]["container"] = {"status": "error", "error": container_result.stderr.strip()}
                result["status"] = "unhealthy"
        except subprocess.TimeoutExpired:
            result["components"]["container"] = {"status": "timeout"}
            result["status"] = "unhealthy"
        except Exception as e:
            result["components"]["container"] = {"status": "error", "error": str(e)}

        # Check configuration files
        files_ok = True
        file_status: dict[str, str] = {}
        for name, path in [("map_file", MAP_FILE), ("servers_file", SERVERS_FILE)]:
            if os.path.exists(path):
                file_status[name] = "ok"
            else:
                file_status[name] = "missing"
                files_ok = False

        result["components"]["config_files"]["files"] = file_status
        result["components"]["config_files"]["status"] = "ok" if files_ok else "warning"
        if not files_ok:
            result["status"] = "degraded"

        return json.dumps(result, indent=2)

    @mcp.tool()
    def haproxy_domain_health(
        domain: Annotated[str, Field(description="Domain name to check health for (e.g., api.example.com)")]
    ) -> str:
        """Check health status of backend servers for a specific domain.

        Returns JSON with status (healthy/degraded/down/no_servers), server list, and counts.
        """
        if not validate_domain(domain):
            return json.dumps({"error": "Invalid domain format"})

        try:
            backend, _ = get_backend_and_prefix(domain)
        except ValueError as e:
            return json.dumps({"error": str(e)})

        result: dict[str, Any] = {
            "domain": domain,
            "backend": backend,
            "status": "unknown",
            "servers": [],
            "healthy_count": 0,
            "total_count": 0
        }

        try:
            # Get server states
            state_output = haproxy_cmd("show servers state")
            stat_output = haproxy_cmd("show stat")

            # Build status map from stat output (has UP/DOWN/MAINT status)
            status_map: dict[str, dict[str, str]] = {}
            for stat in parse_stat_csv(stat_output):
                if stat["pxname"] == backend and stat["svname"] not in ["FRONTEND", "BACKEND"]:
                    status_map[stat["svname"]] = {
                        "status": stat["status"],
                        "check_status": stat["check_status"],
                        "weight": stat["weight"]
                    }

            # Parse server state for address info
            for line in state_output.split("\n"):
                parts = line.split()
                if len(parts) >= STATE_MIN_COLUMNS and parts[StateField.BE_NAME] == backend:
                    server_name = parts[StateField.SRV_NAME]
                    addr = parts[StateField.SRV_ADDR]
                    port = parts[StateField.SRV_PORT]

                    # Skip disabled servers (0.0.0.0)
                    if addr == "0.0.0.0":
                        continue

                    server_info: dict[str, Any] = {
                        "name": server_name,
                        "addr": f"{addr}:{port}",
                        "status": "unknown"
                    }

                    # Get status from stat output
                    if server_name in status_map:
                        server_info["status"] = status_map[server_name]["status"]
                        server_info["check_status"] = status_map[server_name]["check_status"]
                        server_info["weight"] = status_map[server_name]["weight"]

                    result["servers"].append(server_info)
                    result["total_count"] += 1

                    if server_info["status"] == "UP":
                        result["healthy_count"] += 1

            # Determine overall status
            if result["total_count"] == 0:
                result["status"] = "no_servers"
            elif result["healthy_count"] == result["total_count"]:
                result["status"] = "healthy"
            elif result["healthy_count"] > 0:
                result["status"] = "degraded"
            else:
                result["status"] = "down"

            return json.dumps(result, indent=2)

        except HaproxyError as e:
            return json.dumps({"error": str(e)})

    @mcp.tool()
    def haproxy_get_server_health(
        backend: Annotated[str, Field(default="", description="Optional: Backend name to filter (e.g., 'pool_1'). Empty = all backends")]
    ) -> str:
        """Get health status of all servers (low-level view). For domain-specific, use haproxy_domain_health."""
        if backend and not validate_backend_name(backend):
            return "Error: Invalid backend name (use alphanumeric, underscore, hyphen only)"
        try:
            result = haproxy_cmd("show stat")
            servers = []
            for stat in parse_stat_csv(result):
                if stat["svname"] not in ["FRONTEND", "BACKEND", ""]:
                    if backend and stat["pxname"] != backend:
                        continue
                    servers.append(
                        f"• {stat['pxname']}/{stat['svname']}: {stat['status']} "
                        f"(weight: {stat['weight']}, check: {stat['check_status']})"
                    )
            return "\n".join(servers) if servers else "No servers found"
        except HaproxyError as e:
            return f"Error: {e}"