Hetzner Cloud MCP Server

Instructions

Implementation Reference

• mcp_hetzner/server.py:844-899 (handler)

  The handler function decorated with @mcp.tool() that implements the logic for applying a firewall to specified servers or label-selected resources using the Hetzner Cloud client API. It validates inputs, converts params to domain objects, calls apply_to_resources, and returns actions.
  @mcp.tool() def apply_firewall_to_resources(params: FirewallResourcesParams) -> Dict[str, Any]: """ Apply a firewall to resources. Applies a firewall to multiple resources like servers or server groups by label. Examples: - Apply to server: {"firewall_id": 12345, "resources": [{"type": "server", "server_id": 123}]} - Apply by label: {"firewall_id": 12345, "resources": [{"type": "label_selector", "label_selector": "env=prod"}]} """ try: firewall = client.firewalls.get_by_id(params.firewall_id) if not firewall: return {"error": f"Firewall with ID {params.firewall_id} not found"} # Convert resource parameters to FirewallResource objects resources = [] for resource_param in params.resources: if resource_param.type == "server": if not resource_param.server_id: return {"error": "Server ID is required when resource type is 'server'"} server = client.servers.get_by_id(resource_param.server_id) if not server: return {"error": f"Server with ID {resource_param.server_id} not found"} resource = FirewallResource(type=resource_param.type, server=server) elif resource_param.type == "label_selector": if not resource_param.label_selector: return {"error": "Label selector is required when resource type is 'label_selector'"} label_selector = FirewallResourceLabelSelector(selector=resource_param.label_selector) resource = FirewallResource(type=resource_param.type, label_selector=label_selector) else: return {"error": f"Invalid resource type: {resource_param.type}. Must be 'server' or 'label_selector'"} resources.append(resource) # Apply the firewall to the resources actions = client.firewalls.apply_to_resources(firewall, resources) # Format the response return { "success": True, "actions": [ { "id": action.id, "status": action.status, "command": action.command, "progress": action.progress, "error": action.error, "started": action.started.isoformat() if action.started else None, "finished": action.finished.isoformat() if action.finished else None, } for action in actions ] if actions else None, } except Exception as e: return {"error": f"Failed to apply firewall to resources: {str(e)}"}
• mcp_hetzner/server.py:186-213 (schema)

  Pydantic BaseModel classes defining the input parameters for the tool: FirewallResourceParam for individual resources and FirewallResourcesParams as the top-level input schema requiring firewall_id and list of resources.
  class FirewallResourceParam(BaseModel): type: str = Field(..., description="Type of resource ('server' or 'label_selector')") server_id: Optional[int] = Field(None, description="Server ID (required when type is 'server')") label_selector: Optional[str] = Field(None, description="Label selector (required when type is 'label_selector')") # Create Firewall Parameter Model class CreateFirewallParams(BaseModel): name: str = Field(..., description="Name of the firewall") rules: Optional[List[FirewallRuleParam]] = Field(None, description="List of firewall rules") resources: Optional[List[FirewallResourceParam]] = Field(None, description="List of resources to apply the firewall to") labels: Optional[Dict[str, str]] = Field(None, description="User-defined labels (key-value pairs)") # Update Firewall Parameter Model class UpdateFirewallParams(BaseModel): firewall_id: int = Field(..., description="The ID of the firewall") name: Optional[str] = Field(None, description="New name for the firewall") labels: Optional[Dict[str, str]] = Field(None, description="User-defined labels (key-value pairs)") # Set Firewall Rules Parameter Model class SetFirewallRulesParams(BaseModel): firewall_id: int = Field(..., description="The ID of the firewall") rules: List[FirewallRuleParam] = Field(..., description="List of firewall rules") # Apply/Remove Firewall Resources Parameter Model class FirewallResourcesParams(BaseModel): firewall_id: int = Field(..., description="The ID of the firewall") resources: List[FirewallResourceParam] = Field(..., description="List of resources to apply/remove the firewall to/from")