83 lines
3.2 KiB
Python
83 lines
3.2 KiB
Python
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"""Strict parsing of confirmed paired-end WGS sample manifests."""
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from __future__ import annotations
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from dataclasses import dataclass
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from pathlib import Path
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import re
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import yaml
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_SAMPLE_ID = re.compile(r"^[A-Za-z0-9][A-Za-z0-9_.-]*$")
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_FASTQ_SUFFIXES = (".fastq", ".fastq.gz", ".fq", ".fq.gz")
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_FORBIDDEN_RECORD_KEYS = {"include", "exclude", "group_role", "read1", "read2"}
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class _DuplicateKeySafeLoader(yaml.SafeLoader):
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pass
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def _construct_mapping(loader: _DuplicateKeySafeLoader, node: yaml.MappingNode, deep: bool = False) -> dict[object, object]:
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mapping: dict[object, object] = {}
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for key_node, value_node in node.value:
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key = loader.construct_object(key_node, deep=deep)
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if key in mapping:
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raise ValueError(f"duplicate key: {key}")
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mapping[key] = loader.construct_object(value_node, deep=deep)
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return mapping
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_DuplicateKeySafeLoader.add_constructor(yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG, _construct_mapping)
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@dataclass(frozen=True)
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class WgsSample:
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sample_id: str
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r1: Path
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r2: Path
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def _read_path(value: object, *, field: str, yaml_parent: Path) -> Path:
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if not isinstance(value, str) or not value.strip():
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raise ValueError(f"{field} must be a non-empty path")
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path = Path(value)
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if not path.is_absolute():
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path = yaml_parent / path
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if not path.name.endswith(_FASTQ_SUFFIXES):
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raise ValueError(f"{field} has an unsupported FASTQ suffix")
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if not path.is_file():
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raise ValueError(f"{field} must be an existing file")
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if path.stat().st_size == 0:
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raise ValueError(f"{field} must be non-empty")
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return path
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def load_wgs_samples(path: str | Path) -> tuple[WgsSample, ...]:
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"""Load explicitly listed, valid paired-end samples from a YAML document."""
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config_path = Path(path)
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with config_path.open(encoding="utf-8") as handle:
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data = yaml.load(handle, Loader=_DuplicateKeySafeLoader)
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if not isinstance(data, dict) or not isinstance(data.get("samples"), dict) or not data["samples"]:
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raise ValueError("wgs_samples.yaml must contain a non-empty samples mapping")
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if set(data) != {"samples"}:
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raise ValueError("wgs_samples.yaml accepts only the samples mapping")
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samples: list[WgsSample] = []
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for raw_id, record in data["samples"].items():
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if not isinstance(raw_id, str) or not _SAMPLE_ID.fullmatch(raw_id):
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raise ValueError("sample ID is unsafe")
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if not isinstance(record, dict):
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raise ValueError(f"sample {raw_id} must be a dictionary")
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forbidden = _FORBIDDEN_RECORD_KEYS.intersection(record)
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if forbidden:
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raise ValueError(f"sample {raw_id} contains prohibited field {sorted(forbidden)[0]}")
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if set(record) != {"r1", "r2"}:
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raise ValueError(f"sample {raw_id} must contain only r1 and r2")
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r1 = _read_path(record["r1"], field=f"sample {raw_id} r1", yaml_parent=config_path.parent)
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r2 = _read_path(record["r2"], field=f"sample {raw_id} r2", yaml_parent=config_path.parent)
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if r1 == r2:
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raise ValueError(f"sample {raw_id} r1 and r2 must be different files")
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samples.append(WgsSample(raw_id, r1, r2))
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return tuple(sorted(samples, key=lambda sample: sample.sample_id))
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