Validobj

Validobj is library that takes semistructured data (for example JSON and YAML configuration files) and converts it to more structured Python objects. It places the emphasis on:

• Good error messages (rather than avoiding extra work in the error handling code).
• Schema defined in terms of dataclasses and other high level objects such as enums, as well as a subset of the typing module.
• Simplicity of implementation (rather than full generality).

Validobj requires a modern Python version and has no other dependencies. It progressively supports typing features as they are implemented in the standard library and language: A limited subset of the parsing facilities work with Python 3.8, which is the minimum version. The custom validation module requires at least Python 3.9.

Documentation

https://validobj.readthedocs.io/en/latest/

Example

1. Define a schema using dataclasses

   importdataclassesimportenumfromtypingimportLiteralclassDiskPermissions(enum.Flag):
   READ=enum.auto()
   WRITE=enum.auto()
   EXECUTE=enum.auto()
   @dataclasses.dataclassclassJob:
   name: stros: set[Literal['windows', 'mac', 'linux']]
   script_path: strframework_version: tuple[int, int] = (1, 0)
   disk_permissions: DiskPermissions=DiskPermissions.READ@dataclasses.dataclassclassCIConf:
   stages: list[Job]
   global_environment: dict[str, str] =dataclasses.field(default_factory=dict)

2. Process a dictionary input into it using Validobj

   fromvalidobjimportparse_inputinp= {
   'global_environment': {'CI_ACTIVE': '1'},
   'stages': [
   {
   'name': 'compile',
   'os': ['linux', 'mac'],
   'script_path': 'build.sh',
   'disk_permissions': ['READ', 'WRITE', 'EXECUTE'],
   },
   {
   'name': 'test',
   'os': ['linux', 'mac'],
   'script_path': 'test.sh',
   'framework_version': [4, 0],
   },
   ],
   }
   print(parse_input(inp, CIConf))
   # This results in a dataclass instance with the correct types:## CIConf(stages=[# Job(name='compile',# os={'linux', 'mac'},# script_path='build.sh',# framework_version=(1, 0),# disk_permissions=<DiskPermissions.READ|WRITE|EXECUTE: 7>),# Job(name='test',# os={'linux', 'mac'},# script_path='test.sh',# framework_version=(4, 0),# disk_permissions=<DiskPermissions.READ: 1>)],# global_environment={'CI_ACTIVE': '1'}# )

The set of applied transformations as well as the interface to customise processing are described in the documentation

Installation

The package can be installed with pip:

python3 -m pip install validobj

As well as with conda, from the conda-forge channel:

conda install validobj -c conda-forge

The code is hosted at

https://github.com/Zaharid/validobj