Refactor UI assets and harden quality checks

karldns/dns/rfc2136.py

@@ -1,67 +1,114 @@
 from __future__ import annotations
 
+from dataclasses import dataclass
+from typing import Any, Protocol
+
 from ..models import UpdateResult
 from ..settings import DdnsSettings
 from .base import DnsProviderError
 
 
+class _RcodeResponse(Protocol):
+    def rcode(self) -> int: ...
+
+
+@dataclass(frozen=True, slots=True)
+class _RecordUpdate:
+    ttl: int
+    record_type: str
+    value: str | None
+    enabled: bool
+
+
 def publish_rfc2136(result: UpdateResult, settings: DdnsSettings) -> None:
     if not settings.rfc2136_server:
         return
 
-    import dns.exception
-    import dns.query
-    import dns.rcode
-    import dns.tsigkeyring
-    import dns.update
-
-    keyring = None
-    if settings.rfc2136_key_name and settings.rfc2136_key_secret:
-        keyring = dns.tsigkeyring.from_text({settings.rfc2136_key_name: settings.rfc2136_key_secret})
-
-    zone = settings.rfc2136_zone or ".".join(result.hostname.split(".")[1:])
-    update = dns.update.Update(zone, keyring=keyring)
-    relative = result.hostname.removesuffix("." + zone).rstrip(".") or "@"
-    if result.update_ipv4 and result.ipv4:
-        update.replace(relative, settings.ttl, "A", result.ipv4)
-    elif result.update_ipv4:
-        update.delete(relative, "A")
-    if result.update_ipv6 and result.ipv6:
-        update.replace(relative, settings.ttl, "AAAA", result.ipv6)
-    elif result.update_ipv6:
-        update.delete(relative, "AAAA")
-    try:
-        response = dns.query.tcp(update, settings.rfc2136_server, timeout=5)
-    except dns.exception.DNSException as exc:
-        raise DnsProviderError("RFC2136 DNS update failed") from exc
-    rcode = response.rcode()
-    if rcode != 0:
-        raise DnsProviderError(f"RFC2136 update failed: {dns.rcode.to_text(rcode)}")
+    update, relative = _rfc2136_update(result.hostname, settings)
+    _apply_update_records(update, relative, result, settings)
+    _send_rfc2136_update(update, settings.rfc2136_server, "update")
 
 
 def delete_rfc2136_records(hostname: str, settings: DdnsSettings) -> None:
     if not settings.rfc2136_server:
         return
 
+    update, relative = _rfc2136_update(hostname, settings)
+    update.delete(relative, "A")
+    update.delete(relative, "AAAA")
+    _send_rfc2136_update(update, settings.rfc2136_server, "delete")
+
+
+def _rfc2136_update(hostname: str, settings: DdnsSettings) -> tuple[Any, str]:
+    import dns.update
+
+    zone = _rfc2136_zone(hostname, settings)
+    update = dns.update.Update(zone, keyring=_rfc2136_keyring(settings))
+    return update, _rfc2136_relative_name(hostname, zone)
+
+
+def _rfc2136_zone(hostname: str, settings: DdnsSettings) -> str:
+    return settings.rfc2136_zone or ".".join(hostname.split(".")[1:])
+
+
+def _rfc2136_relative_name(hostname: str, zone: str) -> str:
+    hostname = hostname.rstrip(".")
+    zone = zone.rstrip(".")
+    if hostname == zone:
+        return "@"
+    return hostname.removesuffix("." + zone).rstrip(".") or "@"
+
+
+def _rfc2136_keyring(settings: DdnsSettings) -> Any | None:
+    if not settings.rfc2136_key_name or not settings.rfc2136_key_secret:
+        return None
+
+    import dns.tsigkeyring
+
+    return dns.tsigkeyring.from_text({settings.rfc2136_key_name: settings.rfc2136_key_secret})
+
+
+def _apply_update_records(update: Any, relative: str, result: UpdateResult, settings: DdnsSettings) -> None:
+    _apply_record_update(
+        update,
+        relative,
+        _RecordUpdate(ttl=settings.ttl, record_type="A", value=result.ipv4, enabled=result.update_ipv4),
+    )
+    _apply_record_update(
+        update,
+        relative,
+        _RecordUpdate(ttl=settings.ttl, record_type="AAAA", value=result.ipv6, enabled=result.update_ipv6),
+    )
+
+
+def _apply_record_update(
+    update: Any,
+    relative: str,
+    record: _RecordUpdate,
+) -> None:
+    if not record.enabled:
+        return
+    if record.value is None:
+        update.delete(relative, record.record_type)
+        return
+    update.replace(relative, record.ttl, record.record_type, record.value)
+
+
+def _send_rfc2136_update(update: Any, server: str, operation: str) -> None:
     import dns.exception
     import dns.query
     import dns.rcode
-    import dns.tsigkeyring
-    import dns.update
 
-    keyring = None
-    if settings.rfc2136_key_name and settings.rfc2136_key_secret:
-        keyring = dns.tsigkeyring.from_text({settings.rfc2136_key_name: settings.rfc2136_key_secret})
-
-    zone = settings.rfc2136_zone or ".".join(hostname.split(".")[1:])
-    update = dns.update.Update(zone, keyring=keyring)
-    relative = hostname.removesuffix("." + zone).rstrip(".") or "@"
-    update.delete(relative, "A")
-    update.delete(relative, "AAAA")
     try:
-        response = dns.query.tcp(update, settings.rfc2136_server, timeout=5)
+        response = dns.query.tcp(update, server, timeout=5)
     except dns.exception.DNSException as exc:
-        raise DnsProviderError("RFC2136 DNS delete failed") from exc
+        raise DnsProviderError(f"RFC2136 DNS {operation} failed") from exc
+    _raise_for_rfc2136_response(response, operation)
+
+
+def _raise_for_rfc2136_response(response: _RcodeResponse, operation: str) -> None:
+    import dns.rcode
+
     rcode = response.rcode()
     if rcode != 0:
-        raise DnsProviderError(f"RFC2136 delete failed: {dns.rcode.to_text(rcode)}")
+        raise DnsProviderError(f"RFC2136 {operation} failed: {dns.rcode.to_text(dns.rcode.Rcode(rcode))}")