jps-yaml-schema-validator

A strict, rule-driven YAML validator that verifies configuration files against a YAML-defined schema — supporting rich type checking, required fields, filesystem validation, enumerations, regex constraints, numeric ranges, list validation, and complete aggregated error reporting.

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🚀 Overview

jps-yaml-schema-validator enables configuration-driven applications to validate user-supplied YAML files using a declarative rules file (also YAML).

This library focuses on:

• Strict validation (no silently ignored fields)
• Rich semantic checks
• Human-readable error messages
• Aggregated error reporting (never fail fast)
• CLI + Python API support

Ideal for pipelines, workflow engines (Nextflow/Snakemake), microservices, CLIs, or any software that consumes YAML config files.

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✨ Features

Supported rule types

Rule	Description
required: true	Field must exist
type: string/int/float/bool	Type enforcement
type: file	File must exist, readable, and not empty
type: directory	Must be an existing absolute directory
allowed: [...]	Enumerations
regex: "pattern"	Regex string validation
min_length, max_length	String length constraints
min, max	Numeric range checks
element_type, min_items	List validation
allow_extra_keys	Disable/enable acceptance of unknown keys

Additional capabilities

• Aggregates all validation errors before failing
• Validates the schema file itself
• Robust error messages
• Clear CLI interface
• 100% deterministic behavior

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📘 Example

rules.yaml

name:
  type: string
  required: true

threads:
  type: int
  required: true
  min: 1
  max: 64

input_file:
  type: file
  required: true

mode:
  type: string
  allowed:
    - fast
    - slow

config.yaml

name: "my job"
threads: 12
input_file: input.txt
mode: fast

Validate using CLI

jps-yaml-schema-validate validate \
    --schema rules.yaml \
    --config config.yaml

Output:

✅ Configuration is valid.

❌ Example validation failures

If the user config violates rules:

❌ Validation failed:
  - Missing required key: name
  - Field 'threads' must be >= 1
  - Field 'input_file' must be an existing file

🧨 CLI Usage

jps-yaml-schema-validate validate --schema rules.yaml --config config.yaml

Full help:

jps-yaml-schema-validate --help

🧵 Python API Usage

from jps_yaml_schema_validator import assert_valid_config

schema = {
    "name": {"type": "string", "required": True},
    "threads": {"type": "int", "min": 1, "max": 16},
}

config = {"name": "job1", "threads": 8}

assert_valid_config(schema=schema, config=config)

📦 Installation

From source

make install

From PyPI

pip install jps-yaml-schema-validator

🧪 Development

make fix && make format && make lint
make test

To run tests with coverage:

make test

📜 License

MIT License © Jaideep Sundaram