Initial commit

core/utils.py

@@ -0,0 +1,64 @@
+from typing import Dict, List, Any
+
+from dns import resolver, exception
+
+
+def resolve_cname(hostname: str) -> List[str]:
+    """Resolve CNAME records for a hostname and return targets without trailing dots.
+
+    If there is no CNAME record, this returns an empty list.
+    Raises dns.exception.DNSException on resolver errors.
+    """
+    answers = resolver.resolve(hostname, "CNAME")
+    targets: List[str] = []
+    for rdata in answers:
+        # rdata.target may be a Name object; to_text() yields with trailing dot
+        target = getattr(rdata, "target", None)
+        if target is None:
+            # some dnspython versions use .to_text() directly on rdata
+            text = rdata.to_text()
+        else:
+            text = target.to_text()
+        targets.append(text.rstrip("."))
+    return targets
+
+
+def check_cname_map(cname_map: Dict[str, str]) -> List[Dict[str, Any]]:
+    """Check a mapping of hostname -> expected CNAME target.
+
+    Returns a list of result dicts: {
+      'hostname': str,
+      'expected': str,
+      'actual': List[str],
+      'ok': bool,
+      'error': Optional[str]
+    }
+    """
+    results: List[Dict[str, Any]] = []
+    for hostname, expected in cname_map.items():
+        expected_norm = expected.rstrip(".").lower()
+        try:
+            actual_targets = resolve_cname(hostname)
+            actual_norm = [t.lower() for t in actual_targets]
+            ok = expected_norm in actual_norm
+            results.append({
+                "hostname": hostname,
+                "expected": expected,
+                "actual": actual_targets,
+                "ok": ok,
+                "error": None,
+            })
+        except exception.DNSException as e:
+            results.append({
+                "hostname": hostname,
+                "expected": expected,
+                "actual": [],
+                "ok": False,
+                "error": str(e),
+            })
+    return results
+
+
+def bytes_to_gb(num_bytes: int) -> float:
+    """Convert bytes to gigabytes (GB, 1024^3)."""
+    return round(num_bytes / (1024 ** 3), 3)