_ is a forbidden character for container (repository)

[dadoonet]

According to Containers naming guide:

A container name must be a valid DNS name, conforming to the following naming rules:

• Container names must start with a letter or number, and can contain only letters, numbers, and the dash (-) character.
• Every dash (-) character must be immediately preceded and followed by a letter or number; consecutive dashes are not permitted in container names.
• All letters in a container name must be lowercase.
• Container names must be from 3 through 63 characters long.

We need to fix the documentation and control that before calling Azure API.

[imotov]

@dadoonet the documentation fix is good, but I think we should either move snapshot name validation from SnapshotService to the repository level and make it possible to override snapshot validation rules by repository implementation or we can try to escape the snapshot name when creating the snapshot. I would prefer the former solution even though it is more involving.

[dadoonet]

@imotov agreed. Having a new method which actually let every repository plugin validate the repository settings would be nice for the future. Something like:

void validateRepositorySettings() throws RepositoryException;

At the moment, I suggest that I first update the documentation.

Wondering when this new feature should come? Within elasticsearch 2.0? Having that in 1.4 will break the plugin compatibility (not a big deal though as I update plugins for every elasticsearch major release).