from_env

langchain_core.utils.utils.from_env(key: str, /) → Callable[[], str]

langchain_core.utils.utils.from_env(key: str, /, *, default: str) → Callable[[], str]

langchain_core.utils.utils.from_env(key: str, /, *, error_message: str) → Callable[[], str]

langchain_core.utils.utils.from_env(key: str, /, *, default: str, error_message: str | None) → Callable[[], str]

langchain_core.utils.utils.from_env(key: str, /, *, default: None, error_message: str | None) → Callable[[], str | None]

Create a factory method that gets a value from an environment variable.

Parameters:

• key – The environment variable to look up.

• default – The default value to return if the environment variable is not set.

• error_message – the error message which will be raised if the key is not found and no default value is provided. This will be raised as a ValueError.