redfish.RedfishConfigError does not implement the error interface

[ian-howell]

Problem description (if applicable)
The current implementation of redfish.RedfishConfigError does not have an Error method, and therefore doesn't implement the error interface. This can be annoying for a user trying to type switch on the error

Proposed change
Implement the Error method on redfish.RedfishConfigError. This error could also benefit from a renaming to more closely match the other errors in airshipctl

[alexander-hughes]

@ian-howell can you provide more information on this issue?

[ian-howell]

Sure. Go has a builtin interface called error. Basically, any struct that has the following method:

func (s myStruct) Error() string

implements the error interface, and can be used like a builtin error. That means we can do useful things such as check what kind of error we've received using errors.Is and errors.As.

This issue simply requires adding that method to the redfish error, and as mentioned, renaming it to match the conventions of other errors in airshipctl (e.g. ErrMissingConfig, ErrNotImplemented, etc)

[alexander-hughes]

Tracking work in Gerrit