refactor: Modularize MCP server with command batching
- Split monolithic mcp/server.py (1874 lines) into haproxy_mcp/ package:
- config.py: Configuration constants and environment variables
- exceptions.py: Custom exception classes
- validation.py: Input validation functions
- haproxy_client.py: HAProxy Runtime API client with batch support
- file_ops.py: Atomic file operations with locking
- utils.py: CSV parsing utilities
- tools/: MCP tools organized by function
- domains.py: Domain management (3 tools)
- servers.py: Server management (7 tools)
- health.py: Health checks (3 tools)
- monitoring.py: Monitoring (4 tools)
- configuration.py: Config management (4 tools)
- Add haproxy_cmd_batch() for sending multiple commands in single TCP connection
- Optimize server operations: 1 connection instead of 2 per server
- Optimize startup restore: All servers in 1 connection (was 2×N)
- Update type hints to Python 3.9+ style (built-in generics)
- Remove unused imports and functions
- Update CLAUDE.md with new structure and performance notes
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
This commit is contained in:
kaffa
475
haproxy_mcp/tools/servers.py
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475
haproxy_mcp/tools/servers.py
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@@ -0,0 +1,475 @@
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"""Server management tools for HAProxy MCP Server."""
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import json
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import time
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from typing import Annotated
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from pydantic import Field
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from ..config import (
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MAX_SLOTS,
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MAX_BULK_SERVERS,
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MAX_SERVERS_JSON_SIZE,
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StateField,
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StatField,
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STATE_MIN_COLUMNS,
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)
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from ..exceptions import HaproxyError
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from ..validation import validate_domain, validate_ip, validate_backend_name
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from ..haproxy_client import haproxy_cmd, haproxy_cmd_checked, haproxy_cmd_batch
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from ..file_ops import (
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get_backend_and_prefix,
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load_servers_config,
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add_server_to_config,
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remove_server_from_config,
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)
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def configure_server_slot(backend: str, server_prefix: str, slot: int, ip: str, http_port: int) -> str:
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"""Configure a server slot in HAProxy.
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Args:
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backend: Backend name (e.g., 'pool_1')
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server_prefix: Server name prefix (e.g., 'pool_1')
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slot: Slot number (1-10)
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ip: Server IP address
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http_port: HTTP port
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Returns:
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Server name that was configured
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Raises:
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HaproxyError: If HAProxy command fails
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"""
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server = f"{server_prefix}_{slot}"
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# Batch both commands in single TCP connection
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haproxy_cmd_batch([
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f"set server {backend}/{server} addr {ip} port {http_port}",
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f"set server {backend}/{server} state ready"
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])
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return server
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def register_server_tools(mcp):
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"""Register server management tools with MCP server."""
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@mcp.tool()
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def haproxy_list_servers(
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domain: Annotated[str, Field(description="Domain name to list servers for (e.g., api.example.com)")]
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) -> str:
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"""List all servers for a domain with slot numbers, addresses, and status (UP/DOWN/MAINT).
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Example:
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haproxy_list_servers("api.example.com")
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# Output: pool_1_1: 10.0.0.1:8080 (UP)
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# pool_1_2: 10.0.0.2:8080 (UP)
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"""
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if not validate_domain(domain):
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return "Error: Invalid domain format"
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try:
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backend, _ = get_backend_and_prefix(domain)
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servers = []
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state = haproxy_cmd("show servers state")
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for line in state.split("\n"):
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parts = line.split()
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if len(parts) >= STATE_MIN_COLUMNS and parts[StateField.BE_NAME] == backend:
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addr = parts[StateField.SRV_ADDR]
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status = "active" if addr != "0.0.0.0" else "disabled"
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servers.append(
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f"• {parts[StateField.SRV_NAME]}: {addr}:{parts[StateField.SRV_PORT]} ({status})"
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)
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if not servers:
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return f"Backend {backend} not found"
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return f"Servers for {domain} ({backend}):\n" + "\n".join(servers)
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except (HaproxyError, ValueError) as e:
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return f"Error: {e}"
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@mcp.tool()
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def haproxy_add_server(
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domain: Annotated[str, Field(description="Domain name to add server to (e.g., api.example.com)")],
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slot: Annotated[int, Field(description="Server slot number 1-10, or 0 for auto-select next available slot")],
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ip: Annotated[str, Field(description="Server IP address (IPv4 like 10.0.0.1 or IPv6 like 2001:db8::1)")],
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http_port: Annotated[int, Field(default=80, description="HTTP port for backend connection (default: 80)")]
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) -> str:
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"""Add a server to a domain's backend pool for load balancing.
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Each domain can have up to 10 servers (slots 1-10). HAProxy distributes traffic
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across all configured servers using round-robin.
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Example: haproxy_add_server("api.example.com", slot=1, ip="10.0.0.1", http_port=8080)
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"""
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if not validate_domain(domain):
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return "Error: Invalid domain format"
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if not ip:
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return "Error: IP address is required"
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if not validate_ip(ip):
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return "Error: Invalid IP address format"
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if not (1 <= http_port <= 65535):
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return "Error: Port must be between 1 and 65535"
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try:
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backend, server_prefix = get_backend_and_prefix(domain)
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# Auto-select slot if slot <= 0
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if slot <= 0:
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state = haproxy_cmd("show servers state")
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used_slots: set[int] = set()
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for line in state.split("\n"):
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parts = line.split()
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if len(parts) >= STATE_MIN_COLUMNS and parts[StateField.BE_NAME] == backend:
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if parts[StateField.SRV_ADDR] != "0.0.0.0":
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# Extract slot number from server name (e.g., pool_1_3 -> 3)
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server_name = parts[StateField.SRV_NAME]
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try:
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used_slots.add(int(server_name.rsplit("_", 1)[1]))
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except (ValueError, IndexError):
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pass
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for s in range(1, MAX_SLOTS + 1):
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if s not in used_slots:
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slot = s
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break
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else:
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return f"Error: No available slots (all {MAX_SLOTS} slots in use)"
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elif not (1 <= slot <= MAX_SLOTS):
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return f"Error: Slot must be between 1 and {MAX_SLOTS}, or 0/-1 for auto-select"
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# Save to persistent config FIRST (disk-first pattern)
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add_server_to_config(domain, slot, ip, http_port)
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try:
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server = configure_server_slot(backend, server_prefix, slot, ip, http_port)
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return f"Added to {domain} ({backend}) slot {slot}:\n{server} → {ip}:{http_port}"
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except HaproxyError as e:
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# Rollback config on HAProxy failure
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remove_server_from_config(domain, slot)
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return f"Error: {e}"
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except (ValueError, IOError) as e:
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return f"Error: {e}"
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@mcp.tool()
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def haproxy_add_servers(
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domain: Annotated[str, Field(description="Domain name to add servers to (e.g., api.example.com)")],
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servers: Annotated[str, Field(description='JSON array of servers. Each object: {"slot": 1-10, "ip": "10.0.0.1", "http_port": 80}. Example: \'[{"slot":1,"ip":"10.0.0.1"},{"slot":2,"ip":"10.0.0.2"}]\'')]
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) -> str:
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"""Add multiple servers to a domain's backend at once (bulk operation).
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Example: haproxy_add_servers("api.example.com", '[{"slot":1,"ip":"10.0.0.1"},{"slot":2,"ip":"10.0.0.2"}]')
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"""
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if not validate_domain(domain):
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return "Error: Invalid domain format"
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# Check JSON size before parsing
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if len(servers) > MAX_SERVERS_JSON_SIZE:
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return f"Error: servers JSON exceeds maximum size ({MAX_SERVERS_JSON_SIZE} bytes)"
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# Parse JSON array
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try:
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server_list = json.loads(servers)
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except json.JSONDecodeError as e:
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return f"Error: Invalid JSON - {e}"
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if not isinstance(server_list, list):
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return "Error: servers must be a JSON array"
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if not server_list:
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return "Error: servers array is empty"
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if len(server_list) > MAX_BULK_SERVERS:
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return f"Error: Cannot add more than {MAX_BULK_SERVERS} servers at once"
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# Validate all servers first before adding any
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validated_servers = []
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validation_errors = []
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for i, srv in enumerate(server_list):
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if not isinstance(srv, dict):
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validation_errors.append(f"Server {i+1}: must be an object")
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continue
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# Extract and validate slot
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slot = srv.get("slot")
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if slot is None:
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validation_errors.append(f"Server {i+1}: missing 'slot' field")
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continue
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try:
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slot = int(slot)
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except (ValueError, TypeError):
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validation_errors.append(f"Server {i+1}: slot must be an integer")
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continue
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if not (1 <= slot <= MAX_SLOTS):
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validation_errors.append(f"Server {i+1}: slot must be between 1 and {MAX_SLOTS}")
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continue
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# Extract and validate IP
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ip = srv.get("ip")
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if not ip:
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validation_errors.append(f"Server {i+1}: missing 'ip' field")
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continue
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if not validate_ip(ip):
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validation_errors.append(f"Server {i+1}: invalid IP address '{ip}'")
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continue
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# Extract and validate port
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http_port = srv.get("http_port", 80)
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try:
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http_port = int(http_port)
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except (ValueError, TypeError):
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validation_errors.append(f"Server {i+1}: http_port must be an integer")
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continue
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if not (1 <= http_port <= 65535):
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validation_errors.append(f"Server {i+1}: port must be between 1 and 65535")
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continue
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validated_servers.append({"slot": slot, "ip": ip, "http_port": http_port})
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# Return validation errors if any
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if validation_errors:
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return "Validation errors:\n" + "\n".join(f" • {e}" for e in validation_errors)
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# Check for duplicate slots
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slots = [s["slot"] for s in validated_servers]
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if len(slots) != len(set(slots)):
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return "Error: Duplicate slot numbers in servers array"
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# Get backend info
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try:
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backend, server_prefix = get_backend_and_prefix(domain)
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except ValueError as e:
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return f"Error: {e}"
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# Save ALL servers to config FIRST (disk-first pattern)
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for server_config in validated_servers:
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slot = server_config["slot"]
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ip = server_config["ip"]
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http_port = server_config["http_port"]
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add_server_to_config(domain, slot, ip, http_port)
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# Then update HAProxy
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added = []
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errors = []
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failed_slots = []
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try:
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for server_config in validated_servers:
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slot = server_config["slot"]
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ip = server_config["ip"]
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http_port = server_config["http_port"]
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try:
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configure_server_slot(backend, server_prefix, slot, ip, http_port)
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added.append(f"slot {slot}: {ip}:{http_port}")
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except HaproxyError as e:
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failed_slots.append(slot)
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errors.append(f"slot {slot}: {e}")
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except Exception as e:
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# Rollback all saved configs on unexpected error
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for server_config in validated_servers:
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remove_server_from_config(domain, server_config["slot"])
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return f"Error: {e}"
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# Rollback failed slots from config
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for slot in failed_slots:
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remove_server_from_config(domain, slot)
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# Build result message
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result_parts = []
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if added:
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result_parts.append(f"Added {len(added)} servers to {domain} ({backend}):")
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result_parts.extend(f" • {s}" for s in added)
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if errors:
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result_parts.append(f"Failed to add {len(errors)} servers:")
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result_parts.extend(f" • {e}" for e in errors)
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return "\n".join(result_parts) if result_parts else "No servers added"
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@mcp.tool()
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def haproxy_remove_server(
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domain: Annotated[str, Field(description="Domain name to remove server from (e.g., api.example.com)")],
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slot: Annotated[int, Field(description="Server slot number to remove (1-10)")]
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) -> str:
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"""Remove a server from a domain's backend at specified slot.
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Example: haproxy_remove_server("api.example.com", slot=2)
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"""
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if not validate_domain(domain):
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return "Error: Invalid domain format"
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if not (1 <= slot <= MAX_SLOTS):
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return f"Error: Slot must be between 1 and {MAX_SLOTS}"
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try:
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backend, server_prefix = get_backend_and_prefix(domain)
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# Get current server info for potential rollback
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config = load_servers_config()
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old_config = config.get(domain, {}).get(str(slot), {})
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# Remove from persistent config FIRST (disk-first pattern)
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remove_server_from_config(domain, slot)
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try:
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# HTTP only - single server per slot
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server = f"{server_prefix}_{slot}"
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# Batch both commands in single TCP connection
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||||
haproxy_cmd_batch([
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f"set server {backend}/{server} state maint",
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f"set server {backend}/{server} addr 0.0.0.0 port 0"
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])
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return f"Removed server at slot {slot} from {domain} ({backend})"
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except HaproxyError as e:
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# Rollback: re-add config if HAProxy command failed
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if old_config:
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add_server_to_config(domain, slot, old_config.get("ip", ""), old_config.get("http_port", 80))
|
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return f"Error: {e}"
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except (ValueError, IOError) as e:
|
||||
return f"Error: {e}"
|
||||
|
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@mcp.tool()
|
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def haproxy_set_domain_state(
|
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domain: Annotated[str, Field(description="Domain name (e.g., api.example.com)")],
|
||||
state: Annotated[str, Field(description="Target state: 'ready' (normal), 'drain' (stop new connections), or 'maint' (maintenance)")]
|
||||
) -> str:
|
||||
"""Set state for all servers of a domain at once.
|
||||
|
||||
Example: haproxy_set_domain_state("api.example.com", state="drain")
|
||||
|
||||
Example:
|
||||
# Put all servers in maintenance for deployment
|
||||
haproxy_set_domain_state("api.example.com", "maint")
|
||||
|
||||
# Re-enable all servers after deployment
|
||||
haproxy_set_domain_state("api.example.com", "ready")
|
||||
"""
|
||||
if not validate_domain(domain):
|
||||
return "Error: Invalid domain format"
|
||||
if state not in ["ready", "drain", "maint"]:
|
||||
return "Error: State must be 'ready', 'drain', or 'maint'"
|
||||
|
||||
try:
|
||||
backend, _ = get_backend_and_prefix(domain)
|
||||
except ValueError as e:
|
||||
return f"Error: {e}"
|
||||
|
||||
# Get active servers for this domain
|
||||
try:
|
||||
servers_state = haproxy_cmd("show servers state")
|
||||
except HaproxyError as e:
|
||||
return f"Error: {e}"
|
||||
|
||||
changed = []
|
||||
errors = []
|
||||
|
||||
for line in servers_state.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]
|
||||
# Only change state for configured servers (not 0.0.0.0)
|
||||
if addr != "0.0.0.0":
|
||||
try:
|
||||
haproxy_cmd_checked(f"set server {backend}/{server_name} state {state}")
|
||||
changed.append(server_name)
|
||||
except HaproxyError as e:
|
||||
errors.append(f"{server_name}: {e}")
|
||||
|
||||
if not changed and not errors:
|
||||
return f"No active servers found for {domain}"
|
||||
|
||||
result = f"Set {len(changed)} servers to '{state}' for {domain}"
|
||||
if changed:
|
||||
result += ":\n" + "\n".join(f" • {s}" for s in changed)
|
||||
if errors:
|
||||
result += f"\n\nErrors ({len(errors)}):\n" + "\n".join(f" • {e}" for e in errors)
|
||||
|
||||
return result
|
||||
|
||||
@mcp.tool()
|
||||
def haproxy_wait_drain(
|
||||
domain: Annotated[str, Field(description="Domain name to wait for (e.g., api.example.com)")],
|
||||
timeout: Annotated[int, Field(default=30, description="Maximum seconds to wait (default: 30, max: 300)")]
|
||||
) -> str:
|
||||
"""Wait for all active connections to drain from a domain's servers.
|
||||
|
||||
Use after setting servers to 'drain' state before maintenance.
|
||||
|
||||
Example: haproxy_wait_drain("api.example.com", timeout=60)
|
||||
"""
|
||||
if not validate_domain(domain):
|
||||
return "Error: Invalid domain format"
|
||||
if not (1 <= timeout <= 300):
|
||||
return "Error: Timeout must be between 1 and 300 seconds"
|
||||
|
||||
try:
|
||||
backend, _ = get_backend_and_prefix(domain)
|
||||
except ValueError as e:
|
||||
return f"Error: {e}"
|
||||
|
||||
start_time = time.time()
|
||||
while time.time() - start_time < timeout:
|
||||
try:
|
||||
stats = haproxy_cmd("show stat")
|
||||
total_connections = 0
|
||||
for line in stats.split("\n"):
|
||||
parts = line.split(",")
|
||||
if len(parts) > StatField.SCUR and parts[0] == backend and parts[1] not in ["FRONTEND", "BACKEND", ""]:
|
||||
try:
|
||||
scur = int(parts[StatField.SCUR]) if parts[StatField.SCUR] else 0
|
||||
total_connections += scur
|
||||
except ValueError:
|
||||
pass
|
||||
|
||||
if total_connections == 0:
|
||||
elapsed = int(time.time() - start_time)
|
||||
return f"All connections drained for {domain} ({elapsed}s)"
|
||||
|
||||
time.sleep(1)
|
||||
except HaproxyError as e:
|
||||
return f"Error checking connections: {e}"
|
||||
|
||||
return f"Timeout: Connections still active after {timeout}s"
|
||||
|
||||
@mcp.tool()
|
||||
def haproxy_set_server_state(
|
||||
backend: Annotated[str, Field(description="Backend name (e.g., 'pool_1')")],
|
||||
server: Annotated[str, Field(description="Server name (e.g., 'pool_1_1')")],
|
||||
state: Annotated[str, Field(description="'ready' (enable), 'drain' (graceful shutdown), or 'maint' (maintenance)")]
|
||||
) -> str:
|
||||
"""Set server state for maintenance or traffic control.
|
||||
|
||||
Example: haproxy_set_server_state("pool_1", "pool_1_2", "maint")
|
||||
"""
|
||||
if not validate_backend_name(backend):
|
||||
return "Error: Invalid backend name (use alphanumeric, underscore, hyphen only)"
|
||||
if not validate_backend_name(server):
|
||||
return "Error: Invalid server name (use alphanumeric, underscore, hyphen only)"
|
||||
if state not in ["ready", "drain", "maint"]:
|
||||
return "Error: state must be 'ready', 'drain', or 'maint'"
|
||||
try:
|
||||
haproxy_cmd_checked(f"set server {backend}/{server} state {state}")
|
||||
return f"Server {backend}/{server} set to {state}"
|
||||
except HaproxyError as e:
|
||||
return f"Error: {e}"
|
||||
|
||||
@mcp.tool()
|
||||
def haproxy_set_server_weight(
|
||||
backend: Annotated[str, Field(description="Backend name (e.g., 'pool_1')")],
|
||||
server: Annotated[str, Field(description="Server name (e.g., 'pool_1_1')")],
|
||||
weight: Annotated[int, Field(description="Weight 0-256 (higher = more traffic, 0 = disabled)")]
|
||||
) -> str:
|
||||
"""Set server weight for load balancing ratio control.
|
||||
|
||||
Example: haproxy_set_server_weight("pool_1", "pool_1_1", weight=2)
|
||||
"""
|
||||
if not validate_backend_name(backend):
|
||||
return "Error: Invalid backend name (use alphanumeric, underscore, hyphen only)"
|
||||
if not validate_backend_name(server):
|
||||
return "Error: Invalid server name (use alphanumeric, underscore, hyphen only)"
|
||||
if not (0 <= weight <= 256):
|
||||
return "Error: weight must be between 0 and 256"
|
||||
try:
|
||||
haproxy_cmd_checked(f"set server {backend}/{server} weight {weight}")
|
||||
return f"Server {backend}/{server} weight set to {weight}"
|
||||
except HaproxyError as e:
|
||||
return f"Error: {e}"
|
||||
Reference in New Issue
Block a user