refactor: rename package directory fabledscryer → roundtable

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

roundtable/monitors/dns.py

@@ -0,0 +1,71 @@
+from __future__ import annotations
+import asyncio
+import logging
+import socket
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from fabledscryer.core.alerts import record_metric
+from fabledscryer.models.hosts import Host
+from fabledscryer.models.monitors import DnsResult, DnsStatus
+
+logger = logging.getLogger(__name__)
+
+
+async def dns_check(host: Host, session: AsyncSession) -> None:
+    """Resolve host and write dns_result + metrics."""
+    result = await _resolve(host.address)
+
+    if result["resolved"]:
+        resolved_ip = result["ip"]  # first A/AAAA record (stored in DB)
+        all_ips = result["all_ips"]
+
+        # Check against expected IP: pass only if at least one returned record matches
+        if host.dns_expected_ip and host.dns_expected_ip not in all_ips:
+            status = DnsStatus.failed
+            dns_resolved_metric = 0.0
+        else:
+            status = DnsStatus.resolved
+            dns_resolved_metric = 1.0
+
+        # Detect IP change vs most recent successful resolution
+        prev_result = await session.execute(
+            select(DnsResult)
+            .where(DnsResult.host_id == host.id, DnsResult.status == DnsStatus.resolved)
+            .order_by(DnsResult.resolved_at.desc())
+            .limit(1)
+        )
+        prev = prev_result.scalar_one_or_none()
+        ip_changed = 1.0 if (prev and prev.resolved_ip != resolved_ip) else 0.0
+    else:
+        resolved_ip = None
+        status = DnsStatus.failed
+        dns_resolved_metric = 0.0
+        ip_changed = 0.0
+
+    session.add(DnsResult(
+        host_id=host.id,
+        status=status,
+        resolved_ip=resolved_ip,
+    ))
+    await session.flush()
+
+    await record_metric(session, "dns", host.name, "resolved", dns_resolved_metric)
+    await record_metric(session, "dns", host.name, "ip_changed", ip_changed)
+
+
+async def _resolve(address: str) -> dict:
+    """Resolve hostname. Returns all A/AAAA records; stores first as resolved_ip."""
+    try:
+        loop = asyncio.get_running_loop()
+        infos = await loop.run_in_executor(
+            None, socket.getaddrinfo, address, None, socket.AF_UNSPEC, socket.SOCK_STREAM
+        )
+        if infos:
+            all_ips = [info[4][0] for info in infos]
+            return {"resolved": True, "ip": all_ips[0], "all_ips": all_ips}
+        return {"resolved": False, "ip": None, "all_ips": []}
+    except Exception as exc:
+        logger.debug(f"DNS resolution failed for {address}: {exc}")
+        return {"resolved": False, "ip": None, "all_ips": []}