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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.

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