experimental/sources/: pydantic-yaml-1.3.0 metadata and description

Simple index

Adds some YAML functionality to the excellent `pydantic` library.

author_email NowanIlfideme <git@nowan.dev>
  • Programming Language :: Python :: 3 :: Only
  • Development Status :: 5 - Production/Stable
  • Intended Audience :: Developers
  • License :: OSI Approved :: MIT License
  • Topic :: Software Development
  • Typing :: Typed
  • Operating System :: OS Independent
description_content_type text/markdown
keywords pydantic,yaml
license MIT License Copyright (c) 2020 Anatoly Makarevich Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  • github, https://github.com/NowanIlfideme/pydantic-yaml
  • docs, https://pydantic-yaml.readthedocs.io/en/latest/
provides_extras docs
  • pydantic>=1.8
  • ruamel.yaml<0.19.0,>=0.16.0
  • importlib_metadata
  • typing_extensions>=4.5.0
  • setuptools>=61.0.0; extra == "dev"
  • setuptools-scm[toml]>=6.2; extra == "dev"
  • pre-commit==2.21.0; extra == "dev"
  • ruff==0.1.5; extra == "dev"
  • black==23.11.0; extra == "dev"
  • mypy==1.5.1; extra == "dev"
  • pytest==7.4.2; extra == "dev"
  • mkdocs; extra == "docs"
  • mkdocs-material; extra == "docs"
  • mkdocstrings[python]; extra == "docs"
  • pymdown-extensions; extra == "docs"
  • pygments; extra == "docs"
requires_python >=3.8
File Tox results History
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PyPI version Documentation Status Unit Tests

Pydantic-YAML adds YAML capabilities to Pydantic, which is an excellent Python library for data validation and settings management. If you aren't familiar with Pydantic, I would suggest you first check out their docs.

Documentation on ReadTheDocs.org

Basic Usage

from enum import Enum
from pydantic import BaseModel, validator
from pydantic_yaml import parse_yaml_raw_as, to_yaml_str

class MyEnum(str, Enum):
    """A custom enumeration that is YAML-safe."""

    a = "a"
    b = "b"

class InnerModel(BaseModel):
    """A normal pydantic model that can be used as an inner class."""

    fld: float = 1.0

class MyModel(BaseModel):
    """Our custom Pydantic model."""

    x: int = 1
    e: MyEnum = MyEnum.a
    m: InnerModel = InnerModel()

    def _chk_x(cls, v: int) -> int:  # noqa
        """You can add your normal pydantic validators, like this one."""
        assert v > 0
        return v

m1 = MyModel(x=2, e="b", m=InnerModel(fld=1.5))

# This dumps to YAML and JSON respectively
yml = to_yaml_str(m1)
jsn = m1.json()

# This parses YAML as the MyModel type
m2 = parse_yaml_raw_as(MyModel, yml)
assert m1 == m2

# JSON is also valid YAML, so this works too
m3 = parse_yaml_raw_as(MyModel, jsn)
assert m1 == m3

With Pydantic v2, you can also dump dataclasses:

from pydantic import RootModel
from pydantic.dataclasses import dataclass
from pydantic.version import VERSION as PYDANTIC_VERSION
from pydantic_yaml import to_yaml_str

assert PYDANTIC_VERSION >= "2"

class YourType:
    foo: str = "bar"

obj = YourType(foo="wuz")
assert to_yaml_str(RootModel[YourType](obj)) == 'foo: wuz\n'


Currently we use the JSON dumping of Pydantic to perform most of the magic.

This uses the Config inner class, as in Pydantic:

class MyModel(BaseModel):
    # ...
    class Config:
        # You can override these fields, which affect JSON and YAML:
        json_dumps = my_custom_dumper
        json_loads = lambda x: MyModel()
        # As well as other Pydantic configuration:
        allow_mutation = False

You can control some YAML-specfic options via the keyword options:

to_yaml_str(model, indent=4)  # Makes it wider
to_yaml_str(model, map_indent=9, sequence_indent=7)  # ... you monster.

You can additionally pass your own YAML instance:

from ruamel.yaml import YAML
my_writer = YAML(typ="safe")
my_writer.default_flow_style = True
to_yaml_file("foo.yaml", model, custom_yaml_writer=my_writer)

A separate configuration for YAML specifically will be added later, likely in v2.

Breaking Changes for pydantic-yaml V1

The API for pydantic-yaml version 1.0.0 has been greatly simplified!

Mixin Class

This functionality has currently been removed! YamlModel and YamlModelMixin base classes are no longer needed. The plan is to re-add it before v1 fully releases, to allow the .yaml() or .parse_*() methods. However, this will be availble only for pydantic<2.

Versioned Models

This functionality has been removed, as it's questionably useful for most users. There is an example in the docs that's available.