OpenAPI Lambda MCP Server

from __future__ import annotations as _annotations import inspect import warnings from pathlib import Path from typing import TYPE_CHECKING, Annotated, Any, Literal from pydantic import Field, ImportString, field_validator from pydantic.fields import FieldInfo from pydantic_settings import ( BaseSettings, EnvSettingsSource, PydanticBaseSettingsSource, SettingsConfigDict, ) from typing_extensions import Self from fastmcp.utilities.logging import get_logger logger = get_logger(__name__) LOG_LEVEL = Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"] DuplicateBehavior = Literal["warn", "error", "replace", "ignore"] if TYPE_CHECKING: from fastmcp.server.auth.auth import AuthProvider class ExtendedEnvSettingsSource(EnvSettingsSource): """ A special EnvSettingsSource that allows for multiple env var prefixes to be used. Raises a deprecation warning if the old `FASTMCP_SERVER_` prefix is used. """ def get_field_value( self, field: FieldInfo, field_name: str ) -> tuple[Any, str, bool]: if prefixes := self.config.get("env_prefixes"): for prefix in prefixes: self.env_prefix = prefix env_val, field_key, value_is_complex = super().get_field_value( field, field_name ) if env_val is not None: if prefix == "FASTMCP_SERVER_": # Deprecated in 2.8.0 logger.warning( "Using `FASTMCP_SERVER_` environment variables is deprecated. Use `FASTMCP_` instead.", ) return env_val, field_key, value_is_complex return super().get_field_value(field, field_name) class ExtendedSettingsConfigDict(SettingsConfigDict, total=False): env_prefixes: list[str] | None class ExperimentalSettings(BaseSettings): model_config = SettingsConfigDict( env_prefix="FASTMCP_EXPERIMENTAL_", extra="ignore", ) enable_new_openapi_parser: Annotated[ bool, Field( description=inspect.cleandoc( """ Whether to use the new OpenAPI parser. This parser was introduced for testing in 2.11 and will become the default soon. """ ), ), ] = False class Settings(BaseSettings): """FastMCP settings.""" model_config = ExtendedSettingsConfigDict( env_prefixes=["FASTMCP_", "FASTMCP_SERVER_"], env_file=".env", extra="ignore", env_nested_delimiter="__", nested_model_default_partial_update=True, validate_assignment=True, ) def get_setting(self, attr: str) -> Any: """ Get a setting. If the setting contains one or more `__`, it will be treated as a nested setting. """ settings = self while "__" in attr: parent_attr, attr = attr.split("__", 1) if not hasattr(settings, parent_attr): raise AttributeError(f"Setting {parent_attr} does not exist.") settings = getattr(settings, parent_attr) return getattr(settings, attr) def set_setting(self, attr: str, value: Any) -> None: """ Set a setting. If the setting contains one or more `__`, it will be treated as a nested setting. """ settings = self while "__" in attr: parent_attr, attr = attr.split("__", 1) if not hasattr(settings, parent_attr): raise AttributeError(f"Setting {parent_attr} does not exist.") settings = getattr(settings, parent_attr) setattr(settings, attr, value) @classmethod def settings_customise_sources( cls, settings_cls: type[BaseSettings], init_settings: PydanticBaseSettingsSource, env_settings: PydanticBaseSettingsSource, dotenv_settings: PydanticBaseSettingsSource, file_secret_settings: PydanticBaseSettingsSource, ) -> tuple[PydanticBaseSettingsSource, ...]: # can remove this classmethod after deprecated FASTMCP_SERVER_ prefix is # removed return ( init_settings, ExtendedEnvSettingsSource(settings_cls), dotenv_settings, file_secret_settings, ) @property def settings(self) -> Self: """ This property is for backwards compatibility with FastMCP < 2.8.0, which accessed fastmcp.settings.settings """ # Deprecated in 2.8.0 logger.warning( "Using fastmcp.settings.settings is deprecated. Use fastmcp.settings instead.", ) return self home: Path = Path.home() / ".fastmcp" test_mode: bool = False log_enabled: bool = True log_level: LOG_LEVEL = "INFO" @field_validator("log_level", mode="before") @classmethod def normalize_log_level(cls, v): if isinstance(v, str): return v.upper() return v experimental: ExperimentalSettings = ExperimentalSettings() enable_rich_tracebacks: Annotated[ bool, Field( description=inspect.cleandoc( """ If True, will use rich tracebacks for logging. """ ) ), ] = True deprecation_warnings: Annotated[ bool, Field( description=inspect.cleandoc( """ Whether to show deprecation warnings. You can completely reset Python's warning behavior by running `warnings.resetwarnings()`. Note this will NOT apply to deprecation warnings from the settings class itself. """, ) ), ] = True client_raise_first_exceptiongroup_error: Annotated[ bool, Field( default=True, description=inspect.cleandoc( """ Many MCP components operate in anyio taskgroups, and raise ExceptionGroups instead of exceptions. If this setting is True, FastMCP Clients will `raise` the first error in any ExceptionGroup instead of raising the ExceptionGroup as a whole. This is useful for debugging, but may mask other errors. """ ), ), ] = True resource_prefix_format: Annotated[ Literal["protocol", "path"], Field( default="path", description=inspect.cleandoc( """ When perfixing a resource URI, either use path formatting (resource://prefix/path) or protocol formatting (prefix+resource://path). Protocol formatting was the default in FastMCP < 2.4; path formatting is current default. """ ), ), ] = "path" client_init_timeout: Annotated[ float | None, Field( description="The timeout for the client's initialization handshake, in seconds. Set to None or 0 to disable.", ), ] = None # HTTP settings host: str = "127.0.0.1" port: int = 8000 sse_path: str = "/sse" message_path: str = "/messages/" streamable_http_path: str = "/mcp" debug: bool = False # error handling mask_error_details: Annotated[ bool, Field( default=False, description=inspect.cleandoc( """ If True, error details from user-supplied functions (tool, resource, prompt) will be masked before being sent to clients. Only error messages from explicitly raised ToolError, ResourceError, or PromptError will be included in responses. If False (default), all error details will be included in responses, but prefixed with appropriate context. """ ), ), ] = False server_dependencies: list[str] = Field( default_factory=list, description="List of dependencies to install in the server environment", ) # StreamableHTTP settings json_response: bool = False stateless_http: bool = ( False # If True, uses true stateless mode (new transport per request) ) # Auth settings server_auth: Annotated[ str | None, Field( description=inspect.cleandoc( """ Configure the authentication provider for the server by specifying the full module path to an AuthProvider class (e.g., 'fastmcp.server.auth.providers.google.GoogleProvider'). The specified class will be imported and instantiated automatically during FastMCP server creation. Any class that inherits from AuthProvider can be used, including custom implementations. If None, no automatic configuration will take place. This setting is *always* overridden by any auth provider passed to the FastMCP constructor. Note that most auth providers require additional configuration that must be provided via env vars. Examples: - fastmcp.server.auth.providers.google.GoogleProvider - fastmcp.server.auth.providers.jwt.JWTVerifier - mycompany.auth.CustomAuthProvider """ ), ), ] = None include_tags: Annotated[ set[str] | None, Field( default=None, description=inspect.cleandoc( """ If provided, only components that match these tags will be exposed to clients. A component is considered to match if ANY of its tags match ANY of the tags in the set. """ ), ), ] = None exclude_tags: Annotated[ set[str] | None, Field( default=None, description=inspect.cleandoc( """ If provided, components that match these tags will be excluded from the server. A component is considered to match if ANY of its tags match ANY of the tags in the set. """ ), ), ] = None include_fastmcp_meta: Annotated[ bool, Field( default=True, description=inspect.cleandoc( """ Whether to include FastMCP meta in the server's MCP responses. If True, a `_fastmcp` key will be added to the `meta` field of all MCP component responses. This key will contain a dict of various FastMCP-specific metadata, such as tags. """ ), ), ] = True mounted_components_raise_on_load_error: Annotated[ bool, Field( default=False, description=inspect.cleandoc( """ If True, errors encountered when loading mounted components (tools, resources, prompts) will be raised instead of logged as warnings. This is useful for debugging but will interrupt normal operation. """ ), ), ] = False show_cli_banner: Annotated[ bool, Field( default=True, description=inspect.cleandoc( """ If True, the server banner will be displayed when running the server via CLI. This setting can be overridden by the --no-banner CLI flag. Set to False via FASTMCP_SHOW_CLI_BANNER=false to suppress the banner. """ ), ), ] = True @property def server_auth_class(self) -> AuthProvider | None: from fastmcp.utilities.types import get_cached_typeadapter if not self.server_auth: return None # https://github.com/jlowin/fastmcp/issues/1749 # Pydantic imports the module in an ImportString during model validation, but we don't want the server # auth module imported during settings creation as it imports dependencies we aren't ready for yet. # To fix this while limiting breaking changes, we delay the import by only creating the ImportString # when the class is actually needed type_adapter = get_cached_typeadapter(ImportString) auth_class = type_adapter.validate_python(self.server_auth) return auth_class def __getattr__(name: str): """ Used to deprecate the module-level Image class; can be removed once it is no longer imported to root. """ if name == "settings": import fastmcp settings = fastmcp.settings # Deprecated in 2.10.2 if settings.deprecation_warnings: warnings.warn( "`from fastmcp.settings import settings` is deprecated. use `fastmcp.settings` instead.", DeprecationWarning, stacklevel=2, ) return settings raise AttributeError(f"module '{__name__}' has no attribute '{name}'")