backup-tool/app/parser.py

"""Handles parsing a config file from disk."""
import yaml
from pathlib import Path
from typing import List, Union
from specs import Spec, DirectorySpec, VolumeSpec, ContainerSpec
import skeleton


def read_specs_file(path: Union[str, Path]) -> List[Spec]:
    """Read a config file and merge it with the skeleton.

    Args:
        path: path to the yaml config file

    Returns:
        A list of specs, parsed from the config.
    """
    with open(path, "r") as yaml_file:
        data = yaml.safe_load(yaml_file)

    # NOTE shouldn't this be defined as a top-level variable?
    categories = [
        ("directories", DirectorySpec),
        ("volumes", VolumeSpec),
        ("containers", ContainerSpec),
    ]

    specs = []

    for key, class_name in categories:
        if not data["specs"].get(key):
            continue

        # Check what defaults are present
        defaults = {}

        if data.get("defaults"):
            if data["defaults"].get("all"):
                defaults = skeleton.merge(defaults, data["defaults"]["all"])

            if data["defaults"].get(key):
                defaults = skeleton.merge(defaults, data["defaults"][key])

        specs.extend(
            [
                class_name.from_dict(name, spec, defaults)
                for name, spec in data["specs"][key].items()
            ]
        )

    return specs