schematalog-core

The domain contract for Schematalog, a registry and catalog for JSON Schema specifications — and the conformance suite that goes with it.

This is what a storage backend codes against. It deliberately does not depend on the registry application, so implementing a backend does not oblige you to install a web framework.

pip install schematalog-core[testing]

Writing a storage backend

A backend implements five methods — add, get, set_metadata, list_versions and list_names. Three more (get_latest, list_latest, list_predecessors) are derived for you by SchemaRepository, including the rule for which version counts as latest, so you inherit that rather than reimplementing it. Override them only if your store can answer them better.

The contract is written as tests. Subclass it, supply one fixture yielding an empty repository, and it tells you whether your backend is correct:

import pytest
from schematalog.testing import SchemaRepositoryConformance

class TestMyBackend(SchemaRepositoryConformance):
    @pytest.fixture
    def repository(self):
        return MyRepository(...)

Registration is a schematalog.storage entry point naming the URL scheme you answer to; nothing in the registry needs changing. See schematalog-s3 for a complete worked example.

What it contains

• schematalog.domain — Schema, SchemaRepository, the value objects and errors.
• schematalog.testing — the conformance suite and a sample schema to test with.
• schematalog.common — layer-neutral helpers, including a dependency-free JSON Schema ↔ Avro converter.