mcp-hydrolix

"""Environment configuration for the MCP Hydrolix server. This module handles all environment variable configuration with sensible defaults and type conversion. """ from dataclasses import dataclass import os from typing import Optional from enum import Enum from .auth.credentials import HydrolixCredential, ServiceAccountToken, UsernamePassword class TransportType(str, Enum): """Supported MCP server transport types.""" STDIO = "stdio" HTTP = "http" SSE = "sse" @classmethod def values(cls) -> list[str]: """Get all valid transport values.""" return [transport.value for transport in cls] @dataclass class HydrolixConfig: """Configuration for Hydrolix connection settings. This class handles all environment variable configuration with sensible defaults and type conversion. It provides typed methods for accessing each configuration value. Required environment variables: HYDROLIX_HOST: The hostname of the Hydrolix server Optional environment variables (with defaults): HYDROLIX_TOKEN: Service account token to the Hydrolix Server (this or user+password is required) HYDROLIX_USER: The username for authentication (this or token is required) HYDROLIX_PASSWORD: The password for authentication (this or token is required) HYDROLIX_PORT: The port number (default: 8088) HYDROLIX_VERIFY: Verify SSL certificates (default: true) HYDROLIX_CONNECT_TIMEOUT: Connection timeout in seconds (default: 30) HYDROLIX_SEND_RECEIVE_TIMEOUT: Send/receive timeout in seconds (default: 300) HYDROLIX_DATABASE: Default database to use (default: None) HYDROLIX_PROXY_PATH: Path to be added to the host URL. For instance, for servers behind an HTTP proxy (default: None) HYDROLIX_MCP_SERVER_TRANSPORT: MCP server transport method - "stdio", "http", or "sse" (default: stdio) HYDROLIX_MCP_BIND_HOST: Host to bind the MCP server to when using HTTP or SSE transport (default: 127.0.0.1) HYDROLIX_MCP_BIND_PORT: Port to bind the MCP server to when using HTTP or SSE transport (default: 8000) """ def __init__(self) -> None: """Initialize the configuration from environment variables.""" self._validate_required_vars() # Credential to use for clickhouse connections when no per-request credential is provided self._default_credential: Optional[HydrolixCredential] = None # Set the default credential to the service account from the environment, if available if (global_service_account := os.environ.get("HYDROLIX_TOKEN")) is not None: self._default_credential = ServiceAccountToken( global_service_account, f"https://{self.host}/config" ) elif (global_username := os.environ.get("HYDROLIX_USER")) is not None and ( global_password := os.environ.get("HYDROLIX_PASSWORD") ) is not None: # No global service account available. Set the default credential to the username/password # from the environment, if available self._default_credential = UsernamePassword(global_username, global_password) def creds_with(self, request_credential: Optional[HydrolixCredential]) -> HydrolixCredential: if request_credential is not None: return request_credential elif self._default_credential is not None: return self._default_credential else: raise ValueError( "No credentials available for Hydrolix connection. " "Please provide credentials either through HYDROLIX_TOKEN or " "HYDROLIX_USER/HYDROLIX_PASSWORD environment variables, " "or pass credentials explicitly via the creds parameter." ) @property def host(self) -> str: """Get the Hydrolix host. Called during __init__""" return os.environ["HYDROLIX_HOST"] @property def port(self) -> int: """Get the Hydrolix port. Defaults to 8088. Can be overridden by HYDROLIX_PORT environment variable. """ if "HYDROLIX_PORT" in os.environ: return int(os.environ["HYDROLIX_PORT"]) return 8088 @property def database(self) -> Optional[str]: """Get the default database name if set.""" return os.getenv("HYDROLIX_DATABASE") @property def verify(self) -> bool: """Get whether SSL certificate verification is enabled. Default: True """ return os.getenv("HYDROLIX_VERIFY", "true").lower() == "true" @property def connect_timeout(self) -> int: """Get the connection timeout in seconds. Default: 30 """ return int(os.getenv("HYDROLIX_CONNECT_TIMEOUT", "30")) @property def send_receive_timeout(self) -> int: """Get the send/receive timeout in seconds. Default: 300 (Hydrolix default) """ return int(os.getenv("HYDROLIX_SEND_RECEIVE_TIMEOUT", "300")) @property def proxy_path(self) -> Optional[str]: return os.getenv("HYDROLIX_PROXY_PATH") @property def mcp_server_transport(self) -> str: """Get the MCP server transport method. Valid options: "stdio", "http", "sse" Default: "stdio" """ transport = os.getenv("HYDROLIX_MCP_SERVER_TRANSPORT", TransportType.STDIO.value).lower() # Validate transport type if transport not in TransportType.values(): valid_options = ", ".join(f'"{t}"' for t in TransportType.values()) raise ValueError(f"Invalid transport '{transport}'. Valid options: {valid_options}") return transport @property def mcp_bind_host(self) -> str: """Get the host to bind the MCP server to. Only used when transport is "http" or "sse". Default: "127.0.0.1" """ return os.getenv("HYDROLIX_MCP_BIND_HOST", "127.0.0.1") @property def mcp_bind_port(self) -> int: """Get the port to bind the MCP server to. Only used when transport is "http" or "sse". Default: 8000 """ return int(os.getenv("HYDROLIX_MCP_BIND_PORT", "8000")) def get_client_config(self, request_credential: Optional[HydrolixCredential]) -> dict: """ Get the configuration dictionary for clickhouse_connect client. Args: request_credential: Optional credentials to use for this request. If not provided, falls back to the default credential for this HydrolixConfig Returns: dict: Configuration ready to be passed to clickhouse_connect.get_client() Raises: ValueError: If no credentials could be inferred for the request (either from the startup environment or provided in the request) """ config = { "host": self.host, "port": self.port, "secure": True, "verify": self.verify, "connect_timeout": self.connect_timeout, "send_receive_timeout": self.send_receive_timeout, "client_name": "mcp_hydrolix", } # Add optional database if set if self.database: config["database"] = self.database if self.proxy_path: config["proxy_path"] = self.proxy_path # Add credentials config |= self.creds_with(request_credential).clickhouse_config_entries() return config def _validate_required_vars(self) -> None: """Validate that all required environment variables are set. Called during __init__. Raises: ValueError: If any required environment variable is missing. """ missing_vars = [] required_vars = ["HYDROLIX_HOST"] for var in required_vars: if var not in os.environ: missing_vars.append(var) # HYDROLIX_USER and HYDROLIX_PASSWORD must either be both present or both absent if ("HYDROLIX_USER" in os.environ) != ("HYDROLIX_PASSWORD" in os.environ): raise ValueError( "User/password authentication is only partially configured: set both HYDROLIX_USER and HYDROLIX_PASSWORD" ) if missing_vars: raise ValueError(f"Missing required environment variables: {', '.join(missing_vars)}") # Global instance placeholder for the singleton pattern _CONFIG_INSTANCE = None def get_config(): """ Gets the singleton instance of HydrolixConfig. Instantiates it on the first call. """ global _CONFIG_INSTANCE if _CONFIG_INSTANCE is None: # Instantiate the config object here, ensuring load_dotenv() has likely run _CONFIG_INSTANCE = HydrolixConfig() return _CONFIG_INSTANCE