Fix SNMP checker for pysnmp 7.x API

Migrate from deprecated hlapi to v1arch.asyncio with Slim wrapper.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

checkers/snmp.py

@@ -1,13 +1,10 @@
+import asyncio
 import time
 
-from pysnmp.hlapi import (
+from pysnmp.hlapi.v1arch.asyncio import (
-    SnmpEngine,
+    Slim,
-    CommunityData,
-    UdpTransportTarget,
-    ContextData,
-    ObjectType,
     ObjectIdentity,
-    getCmd,
+    ObjectType,
 )
 
 from .base import BaseChecker, CheckResult
@@ -15,6 +12,9 @@ from .base import BaseChecker, CheckResult
 
 class SnmpChecker(BaseChecker):
     def check(self) -> CheckResult:
+        return asyncio.run(self._async_check())
+
+    async def _async_check(self) -> CheckResult:
         host = self.config["host"]
         port = self.config.get("port", 161)
         community = self.config.get("community", "public")
@@ -23,15 +23,16 @@ class SnmpChecker(BaseChecker):
 
         start = time.time()
         try:
-            iterator = getCmd(
+            with Slim() as slim:
-                SnmpEngine(),
+                error_indication, error_status, error_index, var_binds = await slim.get(
-                CommunityData(community),
+                    community,
-                UdpTransportTarget((host, port), timeout=timeout_val, retries=1),
+                    host,
-                ContextData(),
+                    port,
-                ObjectType(ObjectIdentity(oid))
+                    ObjectType(ObjectIdentity(oid)),
-            )
+                    timeout=timeout_val,
+                    retries=1
+                )
 
-            error_indication, error_status, error_index, var_binds = next(iterator)
             response_time = (time.time() - start) * 1000  # ms
 
             if error_indication: