Is pysnmp thread-safe?

If I want to execute concurrent `pysnmp` threads with `cmdgen.CommandGenerator().nextCmd()`, is `pysnmp` thread-safe? When I test it, I have not seen issues that would indicate a problem; however, I have not run `pysnmp` with threading before and the results of these queries will be used to make business decisions, so I would like to get a definitive answer to `pysnmp`'s thread-safety. ``` from threading import Thread import time # See SNMP.py module at the bottom of the question from SNMP import v2c class SNMP_Walk_Thread(Thread): def __init__(self, address='127.0.0.1', oid='sysDescr'): Thread.__init__(self) self.address = address self.oid = oid self.results = None def run(self): self.snmp = v2c(self.address) self.results = self.snmp.walk(self.oid) if __name__=='__main__': managers = set() finished = set() start = time.time() for addr in ['172.25.116.20', '172.25.116.21', '172.25.116.22', '172.25.116.5']: print "Calling %s(address=%s)" % ('SNMP_Walk_Thread', addr) poll = SNMP_Walk_Thread(address=addr) poll.start(); managers.add(poll) while (len(finished)<len(managers)): for instance in managers.difference(finished): instance.join(0.5) if not instance.is_alive(): finished.add(instance) print "RESULT:", instance.results print " Execution time: %0.3f seconds" % ((time.time()-start)) ``` ``` """SNMP.py (Updated to include single CommandGenerator() instances per thread, as suggested in Ilya's answer""" from collections import namedtuple as NT from datetime import datetime import string import re from pysnmp.entity.rfc3413.oneliner import cmdgen from pysnmp.smi import builder, view, error from numpy import int64, float64 # NOTE!!! # It is best to install the pysnmp-mibs package from pypi... this makes # a lot of symbolic MIB names "just work" # See this link below for many oneliner examples... # http://pysnmp.sourceforge.net/examples/4.x/v3arch/oneliner/index.html class v2c(object): """Build an SNMPv2c manager object""" def __init__(self, ipaddr=None, device=None, community='Public', retries=3, timeout=9): self.device = device self.ipaddr = ipaddr self.community = community self.SNMPObject = NT('SNMPObject', ['modName', 'datetime', 'symName', 'index', 'value']) self.SNMPIndexed = NT('SNMPIndexed', ['modName', 'datetime', 'symName', 'index', 'value']) self.query_timeout = float(timeout)/int(retries) self.query_retries = int(retries) self._index = None self.cmdGen = cmdgen.CommandGenerator() #mibBuilder = builder.MibBuilder() #mibPath = mibBuilder.getMibPath()+('/opt/python/Models/Network/MIBs',) #mibBuilder.setMibPath(*mibPath) #mibBuilder.loadModules( # 'RFC-1213', # ) #mibView = view.MibViewController(mibBuilder) def index(self, oid=None): """Build an SNMP Manager index to reference in get or walk operations. First v2c.index('ifName'). Then, v2c.get_index('ifHCInOctets', 'eth0') or v2c.walk_index('ifHCInOctets'). Instead of referencing a numerical index, the index will refer to the value that was indexed.""" self._index = dict() self._intfobj = dict() snmpidx = self.walk(oid=oid) for ii in snmpidx: ## the dicts below are keyed by the SNMP index number # value below is the text string of the intf name self._index[ii.index] = ii.value # value below is the intf object if not (self.device is None): self._intfobj[ii.index] = self.device.find_match_intf(ii.value, enforce_format=False) def walk_index(self, oid=None): """Example usage, first index with v2c.index('ifName'), then v2c.get_index('ifHCInOctets', 'eth0')""" if not (self._index is None): tmp = list() snmpvals = self.walk(oid=oid) for idx, ii in enumerate(snmpvals): tmp.append([ii.modName, datetime.now(), ii.symName, self._index[ii.index], ii.value]) return map(self.SNMPIndexed._make, tmp) else: raise ValueError, "Must populate with SNMP.v2c.index() first" def walk(self, oid=None): if isinstance(self._format(oid), tuple): errorIndication, errorStatus, errorIndex, \ varBindTable = self.cmdGen.nextCmd( cmdgen.CommunityData('test-agent', self.community), cmdgen.UdpTransportTarget((self.ipaddr, 161), retries=self.query_retries, timeout=self.query_timeout), self._format(oid), ) # Parsing only for now... no return value... self._parse(errorIndication, errorStatus, errorIndex, varBindTable) elif isinstance(oid, str): errorIndication, errorStatus, errorIndex, \ varBindTable = self.cmdGen.nextCmd( # SNMP v2 cmdgen.CommunityData('test-agent', self.community), # Transport cmdgen.UdpTransportTarget((self.ipaddr, 161)), (('', oid),), ) return self._parse_resolve(errorIndication, errorStatus, errorIndex, varBindTable) else: raise ValueError, "Unknown oid format: %s" % oid def get_index(self, oid=None, index=None): """In this case, index should be similar to the values you indexed from... i.e. if you index with ifName, get_index('ifHCInOctets', 'eth0')""" if not (self._index is None) and isinstance(index, str): # Map the interface name provided in index to an ifName index... snmpvals = None for idx, value in self._index.items(): if index == value: # if there is an exact match between the text index and the # snmp index value... snmpvals = self.get(oid=oid, index=idx) break else: # TRY mapping the provided text index into an interface obj _intfobj = self.device.find_match_intf(index) if not (_intfobj is None): for key, val in self._intfobj.items(): if (val==_intfobj): snmpvals = self.get(oid=oid, index=key) break # Ensure we only parse a valid response... if not (snmpvals is None): tmp = [snmpvals.modName, datetime.now(), snmpvals.symName, self._index[snmpvals.index], snmpvals.value] return self.SNMPIndexed._make(tmp) elif not isinstance(index, str): raise ValueError, "index must be a string value" else: raise ValueError, "Must populate with SNMP.v2c.index() first" def get(self, oid=None, index=None): if isinstance(self._format(oid), tuple): errorIndication, errorStatus, errorIndex, \ varBindTable = self.cmdGen.getCmd( cmdgen.CommunityData('test-agent', self.community), cmdgen.UdpTransportTarget((self.ipaddr, 161), retries=self.query_retries, timeout=self.query_timeout), self._format(oid), ) # Parsing only for now... no return value... self._parse(errorIndication, errorStatus, errorIndex, varBindTable) elif isinstance(oid, str) and isinstance(index, int): errorIndication, errorStatus, errorIndex, \ varBindTable = self.cmdGen.getCmd( # SNMP v2 cmdgen.CommunityData('test-agent', self.community), # Transport cmdgen.UdpTransportTarget((self.ipaddr, 161)), (('', oid), index), ) return self._parse_resolve(errorIndication, errorStatus, errorIndex, [varBindTable])[0] else: raise ValueError, "Unknown oid format: %s" % oid def bulkwalk(self, oid=None): """SNMP bulkwalk a device. NOTE: This often is faster, but does not work as well as a simple SNMP walk""" if isinstance(self._format(oid), tuple): errorIndication, errorStatus, errorIndex, varBindTable = self.cmdGen.bulkCmd( cmdgen.CommunityData('test-agent', self.community), cmdgen.UdpTransportTarget((self.ipaddr, 161), retries=self.query_retries, timeout=self.query_timeout), 0, 25, self._format(oid), ) return self._parse(errorIndication, errorStatus, errorIndex, varBindTable) elif isinstance(oid, str): errorIndication, errorStatus, errorIndex, varBindTable = self.cmdGen.bulkCmd( cmdgen.CommunityData('test-agent', self.community), cmdgen.UdpTransportTarget((self.ipaddr, 161), retries=self.query_retries, timeout=self.query_timeout), 0, 25, (('', oid),), ) return self._parse_resolve(errorIndication, errorStatus, errorIndex, varBindTable) else: raise ValueError, "Unknown oid format: %s" % oid def _parse_resolve(self, errorIndication=None, errorStatus=None, errorIndex=None, varBindTable=None): """Parse MIB walks and resolve into MIB names""" retval = list() if errorIndication: print errorIndication else: if errorStatus: print '%s at %s\n' % ( errorStatus.prettyPrint(), varBindTable[-1][int(errorIndex)-1] ) else: for varBindTableRow in varBindTable: for oid, val in varBindTableRow: (symName, modName), indices = cmdgen.mibvar.oidToMibName( self.cmdGen.mibViewController, oid ) val = cmdgen.mibvar.cloneFromMibValue( self.cmdGen.mibViewController, modName, symName, val) # Try to parse the index as an int first, # then as a string try: index = int(string.join(map(lambda v: v.prettyPrint(), indices), '.')) except ValueError: index = str(string.join(map(lambda v: v.prettyPrint(), indices), '.')) # Re-format values as float or integer, if possible... tmp = val.prettyPrint() if re.search(r"""^\s*\d+\s*$""", tmp): value = int64(tmp) elif re.search(r"""^\s*\d+\.\d+\s*$""", tmp): value = float64(tmp) else: value = tmp retval.append(self.SNMPObject._make([modName, datetime.now(), symName, index, value])) return retval def _parse(self, errorIndication, errorStatus, errorIndex, varBindTable): if errorIndication: print errorIndication else: if errorStatus: print '%s at %s\n' % ( errorStatus.prettyPrint(), errorIndex and varBindTable[-1][int(errorIndex)-1] or '?' ) else: for varBindTableRow in varBindTable: for name, val in varBindTableRow: print '%s = %s' % (name.prettyPrint(), val.prettyPrint()) def _format(self, oid): """Format a numerical OID in the form of 1.3.4.1.2.1 into a tuple""" if isinstance(oid, str): if re.search('(\d+\.)+\d+', oid): tmp = list() for ii in oid.split('.'): tmp.append(int(ii)) return tuple(tmp) else: return oid ```