Source code for dagster.core.definitions.logger

from dagster import check
from dagster.core.definitions.config import is_callable_valid_config_arg
from dagster.core.definitions.configurable import AnonymousConfigurableDefinition

from .definition_config_schema import convert_user_facing_definition_config_schema


[docs]class LoggerDefinition(AnonymousConfigurableDefinition):
    """Core class for defining loggers.

    Loggers are pipeline-scoped logging handlers, which will be automatically invoked whenever
    solids in a pipeline log messages.

    Args:
        logger_fn (Callable[[InitLoggerContext], logging.Logger]): User-provided function to
            instantiate the logger. This logger will be automatically invoked whenever the methods
            on ``context.log`` are called from within solid compute logic.
        config_schema (Optional[ConfigSchema]): The schema for the config. Configuration data available in
            `init_context.logger_config`.
        description (Optional[str]): A human-readable description of this logger.
    """

    def __init__(
        self,
        logger_fn,
        config_schema=None,
        description=None,
    ):
        self._logger_fn = check.callable_param(logger_fn, "logger_fn")
        self._config_schema = convert_user_facing_definition_config_schema(config_schema)
        self._description = check.opt_str_param(description, "description")

    @property
    def logger_fn(self):
        return self._logger_fn

    @property
    def config_schema(self):
        return self._config_schema

    @property
    def description(self):
        return self._description

    def copy_for_configured(self, description, config_schema, _):
        return LoggerDefinition(
            config_schema=config_schema,
            description=description or self.description,
            logger_fn=self.logger_fn,
        )


[docs]def logger(config_schema=None, description=None):
    """Define a logger.

    The decorated function should accept an :py:class:`InitLoggerContext` and return an instance of
    :py:class:`python:logging.Logger`. This function will become the ``logger_fn`` of an underlying
    :py:class:`LoggerDefinition`.

    Args:
        config_schema (Optional[ConfigSchema]): The schema for the config. Configuration data available in
            `init_context.logger_config`.
        description (Optional[str]): A human-readable description of the logger.
    """
    # This case is for when decorator is used bare, without arguments.
    # E.g. @logger versus @logger()
    if callable(config_schema) and not is_callable_valid_config_arg(config_schema):
        return LoggerDefinition(logger_fn=config_schema)

    def _wrap(logger_fn):
        return LoggerDefinition(
            logger_fn=logger_fn,
            config_schema=config_schema,
            description=description,
        )

    return _wrap