katachi

Katachi is a Python package for validating, processing, and parsing directory structures against defined schemas.

Note: Katachi is currently under active development and should be considered a work in progress. APIs may change in future releases.

• GitHub repository: https://github.com/nmicovic/katachi/
• Documentation: https://nmicovic.github.io/katachi/

Features

• 📐 Schema-based validation - Define expected directory structures using YAML
• 🧩 Extensible architecture - Create custom validators and actions
• 🔄 Relationship validation - Validate relationships between files (like paired files)
• 🚀 Command-line interface - Easy to use CLI with rich formatting
• 📋 Detailed reports - Get comprehensive validation reports

Installation

Install from PyPI:

pip install katachi

For development:

git clone https://github.com/nmicovic/katachi.git
cd katachi
make install

Quick Start

Define a schema (schema.yaml)

semantical_name: data
type: directory
pattern_name: data
children:
  - semantical_name: image
    pattern_name: "img\\d+"
    type: file
    extension: .jpg
    description: "Image files with numeric identifiers"
  - semantical_name: metadata
    pattern_name: "img\\d+"
    type: file
    extension: .json
    description: "Metadata for image files"
  - semantical_name: file_pairs_check
    type: predicate
    predicate_type: pair_comparison
    description: "Check if images have matching metadata files"
    elements:
      - image
      - metadata

Validate a directory structure

katachi validate schema.yaml target_directory

Command-Line Examples

Validate a simple directory structure:

katachi validate "tests/schema_tests/test_sanity/schema.yaml" "tests/schema_tests/test_sanity/dataset"

Validate a nested directory structure:

katachi validate "tests/schema_tests/test_depth_1/schema.yaml" "tests/schema_tests/test_depth_1/dataset"

Validate paired files (e.g., ensure each .jpg has a matching .json file):

katachi validate "tests/schema_tests/test_paired_files/schema.yaml" "tests/schema_tests/test_paired_files/data"

Python API

from pathlib import Path
from katachi.schema.importer import load_yaml
from katachi.schema.validate import validate_schema

# Load schema from YAML
schema = load_yaml(Path("schema.yaml"), Path("data_directory"))

# Validate directory against schema
report = validate_schema(schema, Path("data_directory"))

# Check if validation passed
if report.is_valid():
    print("Validation successful!")
else:
    print("Validation failed with the following issues:")
    for result in report.results:
        if not result.is_valid:
            print(f"- {result.path}: {result.message}")

Extending Katachi

Custom validators

from pathlib import Path
from katachi.schema.schema_node import SchemaNode
from katachi.validation.core import ValidationResult, ValidatorRegistry

def my_custom_validator(node: SchemaNode, path: Path) -> ValidationResult:
    # Custom validation logic
    return ValidationResult(
        is_valid=True,
        message="Custom validation passed",
        path=path,
        validator_name="custom_validator"
    )

# Register the validator
ValidatorRegistry.register("custom_validator", my_custom_validator)

Custom file processing

from pathlib import Path
from typing import Any
from katachi.schema.actions import register_action, NodeContext

def process_image(node, path: Path, parent_contexts: list[NodeContext], context: dict[str, Any]) -> None:
    # Custom image processing logic
    print(f"Processing image: {path}")
    # Access parent context if needed
    for parent_node, parent_path in parent_contexts:
        if parent_node.semantical_name == "timestamp":
            print(f"Image from date: {parent_path.name}")
            break

# Register the action
register_action("image", process_image)

Contributing

Contributions are welcome! See CONTRIBUTING.md for details.

License

This project is licensed under the terms of the MIT License.