acdl/schemas/README.md

Nova Schemas

Overview

Nova uses JSON Schema draft 2020-12 for all declarative contracts. Schemas are the single source of truth for validation. Every contract, stack instance, pipeline, and policy result in the platform is validated against a schema in this directory before it is consumed by any downstream code path. The resolver, the pipeline runner, the CI workflows, and the test suite all load these schemas directly.

Existing Schemas

Schema	File	Purpose	Where Validated
Nova Consumer Contract	contract.schema.json	Consumer contract validation (id, name, environment, infrastructure map with module versions + inputs)	core/contract_resolver.py, scripts/run_platform.sh Step 1, CI schema-validation job
Nova Target Stack	stack.schema.json	Target Stack instance validation (resources, relationships, composition tree, NFRs)	core/contract_resolver.py (post-resolution), tests/conftest.py
Nova Central Pipeline Contract	pipeline.schema.json	Central CI pipeline contract (stages, commands, triggers, runner)	tests/test_pipeline_contract.py
Nova Central Deployment Pipeline Contract	deploy-pipeline.schema.json	Central deploy pipeline contract (validate → resolve → plan → checkov → confidence → apply → publish → uptime → comment)	tests/test_pipeline_contract.py
Nova PolicyCheckResult	policy_check_result.schema.json	Normalized policy check result schema (the contract between policy engines and the confidence signal)	tests/conftest.py, all adapter tests
Nova Tagging Standard	tagging-standard.json	Required tag set for all taggable AWS resources	adapters/terraform/policy/custom_rules/nova_tagging.py

How to Write a Schema

1. Use JSON Schema draft 2020-12: "$schema": "https://json-schema.org/draft/2020-12/schema".
2. Set $id to https://nova.cloudinit.dev/schemas/<name>.schema.json.
3. Include title and description at the document root.
4. Set type: object at the document root.
5. Declare a required array listing the mandatory top-level property names.
6. Define properties with explicit type, pattern, enum, and description for every field.
7. Use $defs for reusable sub-schemas (e.g. resource definitions, input maps) and $ref them from the main document.

How to Wire a Schema into the Platform

• Contract validation — load the schema in core/contract_resolver.py and in scripts/run_platform.sh Step 1 (validate-contract).
• Stack validation — load the schema in core/contract_resolver.py after the contract is resolved to a stack instance.
• Pipeline validation — load the schema in tests/test_pipeline_contract.py, which validates pipelines/ci.yml and pipelines/contract.yml.
• Module interface validation — structural checks in .github/workflows/platform-test.yml (schema-validation job) that validate each module's interface.json / composition.json.
• Policy result validation — the schema is loaded as a fixture in tests/conftest.py and reused by every adapter test to validate emitted PolicyCheckResult records.

Dependencies

• jsonschema (Python) — installed via requirements-test.txt.
• pyyaml — for YAML contract loading (core/contract_resolver.py, scripts/run_platform.sh, tests).

How to Test Schemas in CI

• tests/test_pipeline_contract.py — validates the pipeline schemas and asserts workflow conformance (byte-identical Gitea/GitHub workflows, same stages/commands/triggers).
• tests/conftest.py — provides stack_schema and policy_check_result_schema fixtures for reuse across the test suite.
• .github/workflows/platform-test.yml schema-validation job — self-validates every schema in schemas/ (each schema is loaded and meta-validated), validates module interfaces, and validates example contracts.

Where to Write Tests

• tests/test_<schema_name>.py for schema-specific tests (e.g. tests/test_contract_schema.py).
• Extend tests/test_pipeline_contract.py for pipeline-schema changes.
• Module interface validation lives in the CI workflow (.github/workflows/platform-test.yml).

Adding a New Schema

1. Create schemas/<name>.schema.json using the draft 2020-12 conventions above.
2. Add it to the CI validation glob in .github/workflows/platform-test.yml (schema-validation job).
3. Write a test in tests/test_<name>.py that loads the schema and validates representative valid/invalid documents.
4. Wire it into the consuming code path (resolver, script, or test) so it is enforced at runtime.