Infrastructure Documentation and Change Management Questions

#!/usr/bin/env python3
import sys, yaml
from datetime import datetime, timezone

EXPECTED_SEVERITIES = {"low","medium","high","critical"}

def parse_iso(ts):
    # support "Z" UTC or offset-aware strings
    try:
        if ts.endswith("Z"):
            return datetime.fromisoformat(ts.replace("Z","+00:00"))
        return datetime.fromisoformat(ts)
    except Exception:
        raise ValueError("timestamp not in ISO 8601 format")

def validate(doc):
    errors = []
    if not isinstance(doc, dict):
        errors.append("Runbook root must be a mapping/object.")
        return errors
    if not doc.get("title"):
        errors.append("Missing or empty: title")
    if not doc.get("owner"):
        errors.append("Missing or empty: owner")
    steps = doc.get("steps")
    if not isinstance(steps, list) or len(steps)==0:
        errors.append("steps must be a non-empty list")
    sev = doc.get("severity","").lower() if doc.get("severity") else ""
    if sev not in EXPECTED_SEVERITIES:
        errors.append(f"severity must be one of {sorted(EXPECTED_SEVERITIES)}")
    ts = doc.get("last-tested")
    if not ts:
        errors.append("Missing: last-tested")
    else:
        try:
            parse_iso(str(ts))
        except ValueError:
            errors.append("last-tested must be ISO 8601 timestamp (e.g. 2023-01-02T15:04:05Z)")
    return errors

def main(path):
    try:
        with open(path) as f:
            doc = yaml.safe_load(f)
    except FileNotFoundError:
        print(f"ERROR: File not found: {path}", file=sys.stderr); sys.exit(2)
    except yaml.YAMLError as e:
        print(f"ERROR: YAML parse error: {e}", file=sys.stderr); sys.exit(2)

    errs = validate(doc)
    if errs:
        print("Runbook validation failed:", file=sys.stderr)
        for e in errs:
            print(f" - {e}", file=sys.stderr)
        sys.exit(3)
    print("Runbook validation OK")
    sys.exit(0)

if __name__=="__main__":
    if len(sys.argv)!=2:
        print("Usage: validate_runbook.py <runbook.yml>", file=sys.stderr); sys.exit(1)
    main(sys.argv[1])