Fix ping-only hosts polled twice per cycle with inconsistent parameters

_collect_snapshot called pulse.ping(count=1) independently from
_process_ping_hosts which called pulse.ping(count=3). This doubled
network load and could show a host as 'up' in the dashboard while
simultaneously firing an 'unreachable' alert, or vice versa.

Now ping_states is computed once in run() using the alert-quality
parameters (count=3) and shared by both snapshot and alert processing.

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

db.py

@@ -3,7 +3,7 @@ import json
 import logging
 import threading
 from contextlib import contextmanager
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from typing import Optional
 
 import pymysql
@@ -281,7 +281,7 @@ def create_suppression(
 ) -> int:
     expires_at = None
     if expires_minutes:
-        expires_at = datetime.utcnow() + timedelta(minutes=int(expires_minutes))
+        expires_at = datetime.now(timezone.utc) + timedelta(minutes=int(expires_minutes))
     with get_conn() as conn:
         with conn.cursor() as cur:
             cur.execute(

monitor.py

@@ -12,7 +12,7 @@ import logging
 import re
 import shlex
 import time
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Dict, List, Optional
 
 import requests
@@ -618,7 +618,7 @@ class LinkStatsCollector:
         return {
             'hosts':          result_hosts,
             'unifi_switches': unifi_switches,
-            'updated':        datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S UTC'),
+            'updated':        datetime.now(timezone.utc).strftime('%Y-%m-%d %H:%M:%S UTC'),
         }
 
     def _compute_unifi_rates(self, raw: Dict[str, dict], now: float) -> Dict[str, dict]:
@@ -653,7 +653,7 @@ class LinkStatsCollector:
 # Helpers
 # --------------------------------------------------------------------------
 def _now_utc() -> str:
-    return datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S UTC')
+    return datetime.now(timezone.utc).strftime('%Y-%m-%d %H:%M:%S UTC')
 
 
 # --------------------------------------------------------------------------
@@ -837,10 +837,10 @@ class NetworkMonitor:
     # ------------------------------------------------------------------
     # Ping-only hosts (no node_exporter)
     # ------------------------------------------------------------------
-    def _process_ping_hosts(self, suppressions: list) -> None:
+    def _process_ping_hosts(self, suppressions: list, ping_states: Dict[str, bool]) -> None:
         for h in self.cfg.get('monitor', {}).get('ping_hosts', []):
             name, ip = h['name'], h['ip']
-            reachable = self.pulse.ping(ip)
+            reachable = ping_states.get(name, False)
 
             if not reachable:
                 sup = db.check_suppressed(suppressions, 'host', name)
@@ -882,6 +882,7 @@ class NetworkMonitor:
     def _collect_snapshot(
         self, iface_states: Dict[str, Dict[str, bool]],
         unifi_devices: Optional[List[dict]] = None,
+        ping_states: Optional[Dict[str, bool]] = None,
     ) -> dict:
         # Accept pre-fetched devices; fall back to empty list if unavailable
         display_unifi = unifi_devices if unifi_devices is not None else []
@@ -910,7 +911,7 @@ class NetworkMonitor:
 
         for h in self.cfg.get('monitor', {}).get('ping_hosts', []):
             name, ip = h['name'], h['ip']
-            reachable = self.pulse.ping(ip, count=1, timeout=2)
+            reachable = (ping_states or {}).get(name, False)
             hosts[name] = {
                 'ip': ip,
                 'interfaces': {},
@@ -921,7 +922,7 @@ class NetworkMonitor:
         return {
             'hosts': hosts,
             'unifi': display_unifi,
-            'updated': datetime.utcnow().isoformat() + 'Z',
+            'updated': datetime.now(timezone.utc).isoformat().replace('+00:00', 'Z'),
         }
 
     # ------------------------------------------------------------------
@@ -942,8 +943,14 @@ class NetworkMonitor:
                 # 2. Fetch UniFi devices once — used by both snapshot and alert processing
                 unifi_devices = self.unifi.get_devices()
 
-                # 3. Collect and store snapshot for dashboard
-                snapshot = self._collect_snapshot(iface_states, unifi_devices)
+                # 3a. Ping-only hosts once — shared by snapshot and alert processing
+                ping_states: Dict[str, bool] = {
+                    h['name']: self.pulse.ping(h['ip'])
+                    for h in self.cfg.get('monitor', {}).get('ping_hosts', [])
+                }
+
+                # 3b. Collect and store snapshot for dashboard
+                snapshot = self._collect_snapshot(iface_states, unifi_devices, ping_states)
                 db.set_state('network_snapshot', snapshot)
                 db.set_state('last_check', _now_utc())
 
@@ -959,7 +966,7 @@ class NetworkMonitor:
                 self._process_interfaces(iface_states, suppressions)
                 self._process_unifi(unifi_devices, suppressions)
 
-                self._process_ping_hosts(suppressions)
+                self._process_ping_hosts(suppressions, ping_states)
 
                 # Housekeeping: deactivate expired suppressions and purge old resolved events
                 db.cleanup_expired_suppressions()