Add snmp_helper library

snmp/snmp_helper.py

@@ -0,0 +1,77 @@
+'''
+Requires the pysnmp version4 library
+
+Example usage:
+
+>>> from snmp_helper import snmp_get_oid,snmp_extract
+>>> 
+>>> COMMUNITY_STRING = '<COMMUNITY>'
+>>> SNMP_PORT = 161
+>>> a_device = ('1.1.1.1', COMMUNITY_STRING, SNMP_PORT)
+
+Use the MIB-2 sysDescr as a test
+>>> snmp_data = snmp_get_oid(a_device, oid='.1.3.6.1.2.1.1.1.0', display_errors=True)
+>>> snmp_data
+
+[(MibVariable(ObjectName(1.3.6.1.2.1.1.1.0)), DisplayString(hexValue='436973636f20494f5320536f6674776172652c204338383020536f667477617265202843383830444154412d554e4956455253414c4b392d4d292c2056657273696f6e2031352e302831294d342c2052454c4541534520534f4654574152452028666331290d0a546563686e6963616c20537570706f72743a20687474703a2f2f7777772e636973636f2e636f6d2f74656368737570706f72740d0a436f707972696768742028632920313938362d3230313020627920436973636f2053797374656d732c20496e632e0d0a436f6d70696c6564204672692032392d4f63742d31302030303a30322062792070726f645f72656c5f7465616d'))]
+
+>>> output = snmp_extract(snmp_data)
+>>> print output
+Cisco IOS Software, C880 Software (C880DATA-UNIVERSALK9-M), Version 15.0(1)M4, RELEASE SOFTWARE (fc1)
+Technical Support: http://www.cisco.com/techsupport
+Copyright (c) 1986-2010 by Cisco Systems, Inc.
+Compiled Fri 29-Oct-10 00:02 by prod_rel_team
+
+'''
+
+from pysnmp.entity.rfc3413.oneliner import cmdgen
+
+
+def snmp_get_oid(a_device, oid='.1.3.6.1.2.1.1.1.0', display_errors=False):
+    '''
+    Retrieve the given OID
+
+    Default OID is MIB2, sysDescr
+
+    a_device is a tuple = (a_host, community_string, snmp_port)
+    '''
+
+    a_host, community_string, snmp_port = a_device
+    snmp_target = (a_host, snmp_port)
+
+    # Create a PYSNMP cmdgen object
+    cmd_gen = cmdgen.CommandGenerator()
+
+    (error_detected, error_status, error_index, snmp_data) = cmd_gen.getCmd(
+        cmdgen.CommunityData(community_string),
+        cmdgen.UdpTransportTarget(snmp_target),
+        oid,
+        lookupNames=True, lookupValues=True
+    )
+
+    if not error_detected:
+        return snmp_data
+    else:
+        if display_errors:
+            print 'ERROR DETECTED: '
+            print '    %-16s %-60s' % ('error_message', error_detected)
+            print '    %-16s %-60s' % ('error_status', error_status)
+            print '    %-16s %-60s' % ('error_index', error_index)
+        return None
+
+
+def snmp_extract(snmp_data):
+    '''
+    Unwrap the SNMP response data and return in a readable format
+
+    Assumes only a single list element is returned
+    '''
+
+    if len(snmp_data) > 1:
+        raise ValueError("snmp_extract only allows a single element")
+
+    if len(snmp_data) == 0:
+        return None
+    else:
+        # Unwrap the data which is returned as a tuple wrapped in a list
+        return snmp_data[0][1].prettyPrint()