Build KarlDNS self-hosted DynDNS service

router_dyndns/dns/__init__.py

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+from __future__ import annotations
+
+from .base import (
+    DnsConfigurationError,
+    DnsProviderError,
+    delete_dns_records,
+    dns_backend_configured,
+    publish_dns,
+    validate_dns_provider_settings,
+)
+from .cloudflare import delete_cloudflare_records, publish_cloudflare
+from .rfc2136 import delete_rfc2136_records, publish_rfc2136
+
+__all__ = [
+    "DnsConfigurationError",
+    "DnsProviderError",
+    "delete_cloudflare_records",
+    "delete_dns_records",
+    "delete_rfc2136_records",
+    "dns_backend_configured",
+    "publish_cloudflare",
+    "publish_dns",
+    "publish_rfc2136",
+    "validate_dns_provider_settings",
+]

router_dyndns/dns/base.py

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+from __future__ import annotations
+
+from ..ddns_models import DdnsSettings, UpdateResult
+
+SUPPORTED_DNS_PROVIDERS = {"", "cloudflare", "rfc2136"}
+
+
+class DnsProviderError(RuntimeError):
+    """Raised for expected DNS provider publish/delete failures."""
+
+
+class DnsConfigurationError(RuntimeError):
+    """Raised when DNS provider settings are invalid at startup."""
+
+
+def publish_dns(result: UpdateResult, settings: DdnsSettings) -> None:
+    validate_dns_provider_settings(settings)
+    provider = _normalized_provider(settings)
+    if provider == "cloudflare":
+        from .cloudflare import publish_cloudflare
+
+        publish_cloudflare(result, settings)
+        return
+    if settings.rfc2136_server or provider == "rfc2136":
+        from .rfc2136 import publish_rfc2136
+
+        publish_rfc2136(result, settings)
+        return
+    if settings.require_dns_provider:
+        raise DnsProviderError("DNS provider is required but not configured")
+
+
+def delete_dns_records(hostname: str, settings: DdnsSettings) -> None:
+    validate_dns_provider_settings(settings)
+    provider = _normalized_provider(settings)
+    if provider == "cloudflare":
+        from .cloudflare import delete_cloudflare_records
+
+        delete_cloudflare_records(hostname, settings)
+        return
+    if settings.rfc2136_server or provider == "rfc2136":
+        from .rfc2136 import delete_rfc2136_records
+
+        delete_rfc2136_records(hostname, settings)
+        return
+    if settings.require_dns_provider:
+        raise DnsProviderError("DNS provider is required but not configured")
+
+
+def dns_backend_configured(settings: DdnsSettings) -> bool:
+    validate_dns_provider_settings(settings)
+    provider = _normalized_provider(settings)
+    return provider == "cloudflare" or provider == "rfc2136" or bool(settings.rfc2136_server)
+
+
+def validate_dns_provider_settings(settings: DdnsSettings) -> None:
+    provider = _normalized_provider(settings)
+    if provider not in SUPPORTED_DNS_PROVIDERS:
+        raise DnsConfigurationError(f"Unsupported DDNS_DNS_PROVIDER: {settings.dns_provider}")
+    if not settings.require_dns_provider:
+        return
+    if provider == "cloudflare":
+        if not settings.cloudflare_api_token or not settings.cloudflare_zone_id:
+            raise DnsConfigurationError(
+                "DDNS_CLOUDFLARE_API_TOKEN and DDNS_CLOUDFLARE_ZONE_ID are required when DDNS_DNS_PROVIDER=cloudflare"
+            )
+        return
+    if provider == "rfc2136" or settings.rfc2136_server:
+        if not settings.rfc2136_server or not settings.rfc2136_zone:
+            raise DnsConfigurationError(
+                "DDNS_RFC2136_SERVER and DDNS_RFC2136_ZONE are required when RFC2136 DNS publishing is enabled"
+            )
+        return
+    raise DnsConfigurationError("DDNS_REQUIRE_DNS_PROVIDER is set but no DNS backend is configured")
+
+
+def _normalized_provider(settings: DdnsSettings) -> str:
+    return settings.dns_provider.strip().lower()

router_dyndns/dns/cloudflare.py

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+from __future__ import annotations
+
+import json
+import urllib.error
+import urllib.parse
+import urllib.request
+
+from ..ddns_models import DdnsSettings, UpdateResult
+from .base import DnsProviderError
+
+
+def publish_cloudflare(result: UpdateResult, settings: DdnsSettings) -> None:
+    if not settings.cloudflare_api_token or not settings.cloudflare_zone_id:
+        raise DnsProviderError("Cloudflare DNS provider is missing required credentials")
+    if result.update_ipv4:
+        _cloudflare_upsert_record(settings, result.hostname, "A", result.ipv4)
+    if result.update_ipv6:
+        _cloudflare_upsert_record(settings, result.hostname, "AAAA", result.ipv6)
+
+
+def delete_cloudflare_records(hostname: str, settings: DdnsSettings) -> None:
+    if not settings.cloudflare_api_token or not settings.cloudflare_zone_id:
+        raise DnsProviderError("Cloudflare DNS provider is missing required credentials")
+    for record_type in ("A", "AAAA"):
+        record = _cloudflare_find_record(settings, hostname, record_type)
+        if record:
+            _cloudflare_request(settings, f"/dns_records/{record['id']}", method="DELETE")
+
+
+def _cloudflare_upsert_record(settings: DdnsSettings, hostname: str, record_type: str, value: str | None) -> None:
+    record = _cloudflare_find_record(settings, hostname, record_type)
+    if value is None:
+        if record:
+            _cloudflare_request(settings, f"/dns_records/{record['id']}", method="DELETE")
+        return
+
+    payload = {
+        "type": record_type,
+        "name": hostname,
+        "content": value,
+        "ttl": settings.ttl,
+        "proxied": False,
+    }
+    if record:
+        _cloudflare_request(settings, f"/dns_records/{record['id']}", method="PATCH", payload=payload)
+    else:
+        _cloudflare_request(settings, "/dns_records", method="POST", payload=payload)
+
+
+def _cloudflare_find_record(settings: DdnsSettings, hostname: str, record_type: str) -> dict[str, str] | None:
+    query = urllib.parse.urlencode({"type": record_type, "name": hostname})
+    response = _cloudflare_request(settings, f"/dns_records?{query}")
+    records = response.get("result", [])
+    return records[0] if records else None
+
+
+def _cloudflare_request(
+    settings: DdnsSettings,
+    path: str,
+    method: str = "GET",
+    payload: dict[str, object] | None = None,
+) -> dict[str, object]:
+    url = f"https://api.cloudflare.com/client/v4/zones/{settings.cloudflare_zone_id}{path}"
+    body = json.dumps(payload).encode("utf-8") if payload is not None else None
+    request = urllib.request.Request(url, data=body, method=method)
+    request.add_header("Authorization", f"Bearer {settings.cloudflare_api_token}")
+    request.add_header("Content-Type", "application/json")
+    try:
+        with urllib.request.urlopen(request, timeout=10) as response:
+            parsed = json.loads(response.read().decode("utf-8"))
+    except urllib.error.HTTPError as exc:
+        raise DnsProviderError(f"Cloudflare API returned HTTP {exc.code}") from exc
+    except urllib.error.URLError as exc:
+        raise DnsProviderError("Cloudflare API request failed") from exc
+    except json.JSONDecodeError as exc:
+        raise DnsProviderError("Cloudflare API returned invalid JSON") from exc
+    if not parsed.get("success", False):
+        raise DnsProviderError("Cloudflare API returned an unsuccessful response")
+    return parsed

router_dyndns/dns/rfc2136.py

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+from __future__ import annotations
+
+from ..ddns_models import DdnsSettings, UpdateResult
+from .base import DnsProviderError
+
+
+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)}")
+
+
+def delete_rfc2136_records(hostname: str, 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(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)
+    except dns.exception.DNSException as exc:
+        raise DnsProviderError("RFC2136 DNS delete failed") from exc
+    rcode = response.rcode()
+    if rcode != 0:
+        raise DnsProviderError(f"RFC2136 delete failed: {dns.rcode.to_text(rcode)}")