Custom errors

This section describes how to create custom exception classes for Meltano.

Creating a custom exception

All new custom exceptions must inherit from meltano.core.error.MeltanoError or one of its subclasses.

The meltano.core.error.MeltanoError initializer takes in a reason argument, which is a string describing the error, as well as the optional instruction argument that can be used to provide additional troubleshooting steps for the user.

from meltano.core.error import MeltanoError


class ScheduleDoesNotExistError(MeltanoError):
    """Occurs when a schedule does not exist."""

    def __init__(self, name: str):
        """Initialize the exception.

        Args:
            name: The name of the schedule that does not exist.
        """
        super().__init__(
            reason=f"Schedule '{name}' does not exist",
            instruction="Use `meltano schedule add` to add a schedule",
        )