Add specific exceptions for typical HTTP status codes

[franzliedke]

This means specific errors can be handled directly by rescuing specific exception classes, instead of rescuing e.g. Restify::ClientError and then checking the exception's code or status.

Open questions:

• Naming? I'd like to avoid the ...Error suffix, if possible, but that would probably mean we need a new namespace. Can subclasses be nested in their own parent class' namespace?
• Which error types do we want to handle? (It's easy to add new types later.) I went through our services and added those that we handle in a special way anywhere.

[franzliedke]

ping @mswart for input

[mswart]

@franzliedke Looks good. Would really like to use it.

[mswart]

I think the important error codes are implemented. Placing the exception classes side the parent class should work: like Restify::ClientError::NotFound

[jgraichen]

Naming? I'd like to avoid the ...Error suffix, if possible, but that would probably mean we need a new namespace. Can subclasses be nested in their own parent class' namespace?

Yes they can but I'd be fine with e.g. Restify::Unauthorized. There shouldn't by any collisions and it is much easier to write and read.

Which error types do we want to handle? (It's easy to add new types later.) I went through our services and added those that we handle in a special way anywhere.

Unless you want to auto generate classes from the Rack status code mapping I'm fine with adding only needed.

[franzliedke]

Okay, updated the class names as coordinated in person. Ready from my side. 😉