Brillo Developer Kit Schemas

The Brillo Developer Kit provides a number of configuration files for use by the end developer. Those files are expressed in XML and the schema files in this directory provide validation, in RELAX NG, for structural correctness.

Additional application layer validation is applied, but the schemas make it easier to know when a given file is semantically valid before exploring other problems.

The current supported schemas are as follows:

• bdk.rng: Specifies how to assemble device and developer software for defined Brillo devices from packs and targets.
• packs.rng: Specifies a collection of resources and how they map into a device.
• targets.rng: Specifies a target device and what tree of packs make up its software.

Format

The schema files are written in RELAX NG.

Testing

When updating the schemas with “breaking” changes, a new version should be added to the version list for all root nodes (bdk-config, packs, targets) and the prior version frozen and archived under “versions/<version_number>”.

Quick Tests

Quick validation can be performed with the xmllint tool:

$ xmllint file.xml - -relaxng bdk.rng

Or with better output:

$ jing bdk.rng file.xml

Or in python with:

from lxml import etree
rng_doc = etree.parse('bdk.rng')
rng = etree.RelaxNG(rng_doc)
doc = etree.parse('file.xml')
print rng.validate(doc) # => False
print rng.error_log # => Errors