Move validation out into its own file without causing circular
import errors.
Fix some of the tests to import from the right place.
Also fix tests that were not using valid test data, as the validation
schema is now firing telling you that you couldn't "just" have this
dict without a build/image config key.
Signed-off-by: Mazz Mosley <mazz@houseofmnowster.com>
jsonschema provides a rich error tree of info, by parsing each error
we can pull out relevant info and re-write the error messages.
This covers current error handling behaviour.
This includes new error handling behaviour for types and formatting of
the ports field.
Signed-off-by: Mazz Mosley <mazz@houseofmnowster.com>
Define a schema that we can pass to jsonschema to validate against the
config a user has supplied. This will help catch a wide variety of common
errors that occur.
If the config does not pass schema validation then it raises an exception
and prints out human readable reasons.
Signed-off-by: Mazz Mosley <mazz@houseofmnowster.com>