Exceptions raised by the Horizon code and the machinery for handling them.
Exception to be raised when trying to create an API resource which already exists.
Used internally to track exceptions that have gone through horizon.exceptions.handle() more than once.
Base exception class for distinguishing our own exception classes.
Error class which can be raised from within a handler to cause an early bailout and redirect at the middleware level.
Raised when a user is trying to make requests and they are not logged in.
The included HorizonMiddleware catches NotAuthenticated and handles it gracefully by displaying an error message and redirecting the user to a login page.
Raised whenever a user attempts to access a resource which they do not have role-based access to (such as when failing the require_roles() decorator).
The included HorizonMiddleware catches NotAuthorized and handles it gracefully by displaying an error message and redirecting the user to a login page.
Generic error to replace all “Not Found”-type API errors.
Generic error to replace any “Recoverable”-type API errors.
Raised when a requested service is not available in the ServiceCatalog returned by Keystone.
Centralized error handling for Horizon.
Because Horizon consumes so many different APIs with completely different Exception types, it’s necessary to have a centralized place for handling exceptions which may be raised.
Exceptions are roughly divided into 3 types:
All other exceptions bubble the stack as normal unless the ignore argument is passed in as True, in which case only unrecognized errors are bubbled.
If the exception is not re-raised, an appropriate wrapper exception class indicating the type of exception that was encountered will be returned.