[change] Optimize getCmd using snmpdump

openwisp · Jul 16, 2021 · c5d932d · c5d932d
1 parent 034475c
commit c5d932d
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Showing 3 changed files with 39 additions and 5 deletions.
diff --git a/netengine/backends/snmp/airos.py b/netengine/backends/snmp/airos.py
@@ -460,12 +460,17 @@ def resources_to_dict(self):
         )
         return result
 
-    def to_dict(self):
-        return self._dict(
+    def to_dict(self, snmpdump=False):
+        if snmpdump:
+            self._snmp_dump = self.walk('1.3.6')
+        result = self._dict(
             {
                 'type': 'DeviceMonitoring',
                 'general': {'uptime': self.uptime, 'local_time': self.local_time},
                 'resources': self.resources_to_dict,
                 'interfaces': self.interfaces_to_dict,
             }
         )
+        if snmpdump:
+            del self._snmp_dump
+        return result
diff --git a/netengine/backends/snmp/base.py b/netengine/backends/snmp/base.py
@@ -12,6 +12,7 @@
 
 from netengine.backends import BaseBackend
 from netengine.exceptions import NetEngineError
+from pysnmp.hlapi import ContextData, ObjectIdentity, ObjectType, SnmpEngine, nextCmd
 
 __all__ = ['SNMP']
 
@@ -94,6 +95,25 @@ def _oid(self, oid):
         # ensure is string (could be unicode)
         return str(oid)
 
+    def walk(self, oid):
+        result = dict()
+        for (errorIndication, errorStatus, errorIndex, varBinds) in nextCmd(
+            SnmpEngine(),
+            self.community,
+            self.transport,
+            ContextData(),
+            ObjectType(ObjectIdentity(oid)),
+            lexicographicMode=True,
+        ):
+            if errorIndication:
+                raise NetEngineError(errorIndication)
+            elif errorStatus:
+                raise NetEngineError(errorStatus)
+            else:
+                for varBind in varBinds:
+                    result[str(varBind[0])] = [None, None, None, [varBind]]
+        return result
+
     def get(self, oid):
         """
         alias to cmdgen.CommandGenerator().getCmd
@@ -107,7 +127,11 @@ def get(self, oid):
             * (1, 3, 6, 1, 2, 1, 1, 5, 0)
         """
         logger.info(f'DEBUG: SNMP GET {self._oid(oid)}')
-        return self._command.getCmd(self.community, self.transport, self._oid(oid))
+        try:
+            # if OID doesn't exist, then pysnmp returns an empty string
+            return self._snmp_dump.get(oid, [None, None, None, [[None, '']]])
+        except AttributeError:
+            return self._command.getCmd(self.community, self.transport, self._oid(oid))
 
     def next(self, oid):
         """

diff --git a/netengine/backends/snmp/openwrt.py b/netengine/backends/snmp/openwrt.py
@@ -545,8 +545,10 @@ def neighbors(self):
             )
         return result
 
-    def to_dict(self):
-        return self._dict(
+    def to_dict(self, snmpdump=False):
+        if snmpdump:
+            self._snmp_dump = self.walk('1.3.6')
+        result = self._dict(
             {
                 'type': 'DeviceMonitoring',
                 'general': {'uptime': self.uptime, "local_time": self.local_time},
@@ -555,3 +557,6 @@ def to_dict(self):
                 'neighbors': self.neighbors,
             }
         )
+        if snmpdump:
+            del self._snmp_dump
+        return result