From 0c0d054e8e949cf7645fd3fe26640ee52893f18a Mon Sep 17 00:00:00 2001 From: Ilya Etingof Date: Wed, 24 Oct 2018 10:14:33 +0200 Subject: [PATCH] Refactor MIB state machine into asynchronous operations (#210) Convert to async MIB instrumentation API (#210) MIB instrumentation API changed to allow for asynchronous managed objects access. The MIB instrumentation methods called by the state machine now return immediately and resume once the callback is called. The built-in SNMPv2-SMI objects are still synchronous. This change is a prerequisite for fully asynchronous managed objects implementation. --- CHANGES.txt | 8 +- .../cmdrsp/implementing-scalar-mib-objects.py | 2 +- .../proxy/command/ipv6-to-ipv4-conversion.py | 2 +- .../proxy/command/v2c-to-v1-conversion.py | 2 +- .../proxy/command/v2c-to-v3-conversion.py | 2 +- .../proxy/command/v3-to-v2c-conversion.py | 2 +- pysnmp/entity/rfc3413/cmdrsp.py | 257 +++++++++--------- pysnmp/entity/rfc3413/ntfrcv.py | 8 +- pysnmp/smi/instrum.py | 221 +++++++++------ 9 files changed, 280 insertions(+), 224 deletions(-) diff --git a/CHANGES.txt b/CHANGES.txt index 3aeb7062..22aeef8e 100644 --- a/CHANGES.txt +++ b/CHANGES.txt @@ -25,15 +25,17 @@ Revision 5.0.0, released 2018-10-?? just var-binds (as var-arg), the rest of the parameters packed into opaque kwargs + * The `readVars`, `readNextVars` and `writeVars` methods of MIB + instrumentation controller return immediately and deliver their + results via a call back. + * CommandResponder application passes `snmpEngine` and optionally user-supplied `cbCtx` object throughout the MIB instrumentation methods. The goal is to let MIB objects access/modify whatever custom Python objects they need while being called back. * CommandResponder refactored to facilitate asynchronous - MIB instrumentation routines. The `readVars`, `readNextVars` and - `writeVars` MIB controller methods return immediately and - deliver their results via a call back. + MIB instrumentation routines. - The high-level API (`hlapi`) extended to cover lightweight SNMP v1arch in hope to ease the use of packet-level SNMP API. diff --git a/examples/v3arch/asyncore/agent/cmdrsp/implementing-scalar-mib-objects.py b/examples/v3arch/asyncore/agent/cmdrsp/implementing-scalar-mib-objects.py index 878f97a9..783c1e6c 100644 --- a/examples/v3arch/asyncore/agent/cmdrsp/implementing-scalar-mib-objects.py +++ b/examples/v3arch/asyncore/agent/cmdrsp/implementing-scalar-mib-objects.py @@ -56,7 +56,7 @@ MibScalar, MibScalarInstance = mibBuilder.importSymbols( class MyStaticMibScalarInstance(MibScalarInstance): # noinspection PyUnusedLocal,PyUnusedLocal - def getValue(self, name, idx): + def getValue(self, name, idx, **context): return self.getSyntax().clone( 'Python %s running on a %s platform' % (sys.version, sys.platform) ) diff --git a/examples/v3arch/asyncore/proxy/command/ipv6-to-ipv4-conversion.py b/examples/v3arch/asyncore/proxy/command/ipv6-to-ipv4-conversion.py index 9e34fd0d..df712179 100644 --- a/examples/v3arch/asyncore/proxy/command/ipv6-to-ipv4-conversion.py +++ b/examples/v3arch/asyncore/proxy/command/ipv6-to-ipv4-conversion.py @@ -96,7 +96,7 @@ class CommandResponder(cmdrsp.CommandResponderBase): v2c.GetNextRequestPDU.tagSet: cmdgen.NextCommandGeneratorSingleRun(), v2c.GetBulkRequestPDU.tagSet: cmdgen.BulkCommandGeneratorSingleRun() } - pduTypes = cmdGenMap.keys() # This app will handle these PDUs + SUPPORTED_PDU_TYPES = cmdGenMap.keys() # This app will handle these PDUs # SNMP request relay def handleMgmtOperation(self, snmpEngine, stateReference, contextName, diff --git a/examples/v3arch/asyncore/proxy/command/v2c-to-v1-conversion.py b/examples/v3arch/asyncore/proxy/command/v2c-to-v1-conversion.py index 3dd64ddf..c676e9b5 100644 --- a/examples/v3arch/asyncore/proxy/command/v2c-to-v1-conversion.py +++ b/examples/v3arch/asyncore/proxy/command/v2c-to-v1-conversion.py @@ -95,7 +95,7 @@ class CommandResponder(cmdrsp.CommandResponderBase): v2c.GetNextRequestPDU.tagSet: cmdgen.NextCommandGeneratorSingleRun(), v2c.GetBulkRequestPDU.tagSet: cmdgen.BulkCommandGeneratorSingleRun() } - pduTypes = cmdGenMap.keys() # This app will handle these PDUs + SUPPORTED_PDU_TYPES = cmdGenMap.keys() # This app will handle these PDUs # SNMP request relay def handleMgmtOperation(self, snmpEngine, stateReference, contextName, diff --git a/examples/v3arch/asyncore/proxy/command/v2c-to-v3-conversion.py b/examples/v3arch/asyncore/proxy/command/v2c-to-v3-conversion.py index f5d6167e..83d4c453 100644 --- a/examples/v3arch/asyncore/proxy/command/v2c-to-v3-conversion.py +++ b/examples/v3arch/asyncore/proxy/command/v2c-to-v3-conversion.py @@ -95,7 +95,7 @@ class CommandResponder(cmdrsp.CommandResponderBase): v2c.GetNextRequestPDU.tagSet: cmdgen.NextCommandGeneratorSingleRun(), v2c.GetBulkRequestPDU.tagSet: cmdgen.BulkCommandGeneratorSingleRun() } - pduTypes = cmdGenMap.keys() # This app will handle these PDUs + SUPPORTED_PDU_TYPES = cmdGenMap.keys() # This app will handle these PDUs # SNMP request relay def handleMgmtOperation(self, snmpEngine, stateReference, contextName, diff --git a/examples/v3arch/asyncore/proxy/command/v3-to-v2c-conversion.py b/examples/v3arch/asyncore/proxy/command/v3-to-v2c-conversion.py index b5d64790..e0c1c4d6 100644 --- a/examples/v3arch/asyncore/proxy/command/v3-to-v2c-conversion.py +++ b/examples/v3arch/asyncore/proxy/command/v3-to-v2c-conversion.py @@ -98,7 +98,7 @@ class CommandResponder(cmdrsp.CommandResponderBase): v2c.GetNextRequestPDU.tagSet: cmdgen.NextCommandGeneratorSingleRun(), v2c.GetBulkRequestPDU.tagSet: cmdgen.BulkCommandGeneratorSingleRun() } - pduTypes = cmdGenMap.keys() # This app will handle these PDUs + SUPPORTED_PDU_TYPES = cmdGenMap.keys() # This app will handle these PDUs # SNMP request relay def handleMgmtOperation(self, snmpEngine, stateReference, contextName, diff --git a/pysnmp/entity/rfc3413/cmdrsp.py b/pysnmp/entity/rfc3413/cmdrsp.py index 8f6bbab5..e2d47f38 100644 --- a/pysnmp/entity/rfc3413/cmdrsp.py +++ b/pysnmp/entity/rfc3413/cmdrsp.py @@ -15,25 +15,41 @@ from pysnmp import debug # 3.2 class CommandResponderBase(object): acmID = 3 # default MIB access control method to use - pduTypes = () + SUPPORTED_PDU_TYPES = () + SMI_ERROR_MAP = { + pysnmp.smi.error.NoAccessError: 'noAccess', + pysnmp.smi.error.WrongTypeError: 'wrongType', + pysnmp.smi.error.WrongLengthError: 'wrongLength', + pysnmp.smi.error.WrongEncodingError: 'wrongEncoding', + pysnmp.smi.error.WrongValueError: 'wrongValue', + pysnmp.smi.error.NoCreationError: 'noCreation', + pysnmp.smi.error.InconsistentValueError: 'inconsistentValue', + pysnmp.smi.error.ResourceUnavailableError: 'resourceUnavailable', + pysnmp.smi.error.CommitFailedError: 'commitFailed', + pysnmp.smi.error.UndoFailedError: 'undoFailed', + pysnmp.smi.error.AuthorizationError: 'authorizationError', + pysnmp.smi.error.NotWritableError: 'notWritable', + pysnmp.smi.error.InconsistentNameError: 'inconsistentName' + } def __init__(self, snmpEngine, snmpContext, cbCtx=None): snmpEngine.msgAndPduDsp.registerContextEngineId( - snmpContext.contextEngineId, self.pduTypes, self.processPdu + snmpContext.contextEngineId, self.SUPPORTED_PDU_TYPES, self.processPdu ) self.snmpContext = snmpContext self.cbCtx = cbCtx self.__pendingReqs = {} - def initiateMgmtOperation(self, snmpEngine, stateReference, contextName, PDU): - pass - def close(self, snmpEngine): snmpEngine.msgAndPduDsp.unregisterContextEngineId( - self.snmpContext.contextEngineId, self.pduTypes + self.snmpContext.contextEngineId, self.SUPPORTED_PDU_TYPES ) self.snmpContext = self.__pendingReqs = None + def releaseStateInformation(self, stateReference): + if stateReference in self.__pendingReqs: + del self.__pendingReqs[stateReference] + def sendVarBinds(self, snmpEngine, stateReference, errorStatus, errorIndex, varBinds): (messageProcessingModel, @@ -105,10 +121,6 @@ class CommandResponderBase(object): _setRequestType = rfc1905.SetRequestPDU.tagSet _counter64Type = rfc1902.Counter64.tagSet - def releaseStateInformation(self, stateReference): - if stateReference in self.__pendingReqs: - del self.__pendingReqs[stateReference] - def processPdu(self, snmpEngine, messageProcessingModel, securityModel, securityName, securityLevel, contextEngineId, contextName, pduVersion, PDU, maxSizeResponseScopedPDU, stateReference): @@ -140,63 +152,11 @@ class CommandResponderBase(object): # 3.2.5 varBinds = v2c.apiPDU.getVarBinds(PDU) - errorStatus, errorIndex = 'noError', 0 debug.logger & debug.flagApp and debug.logger( 'processPdu: stateReference %s, varBinds %s' % (stateReference, varBinds)) - try: - self.initiateMgmtOperation(snmpEngine, stateReference, contextName, PDU) - - # SNMPv2 SMI exceptions - except pysnmp.smi.error.GenError: - errorIndication = sys.exc_info()[1] - debug.logger & debug.flagApp and debug.logger( - 'processPdu: stateReference %s, errorIndication %s' % (stateReference, errorIndication)) - if 'oid' in errorIndication: - # Request REPORT generation - statusInformation['oid'] = errorIndication['oid'] - statusInformation['val'] = errorIndication['val'] - - # PDU-level SMI errors - except pysnmp.smi.error.NoAccessError: - errorStatus, errorIndex = 'noAccess', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.WrongTypeError: - errorStatus, errorIndex = 'wrongType', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.WrongLengthError: - errorStatus, errorIndex = 'wrongLength', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.WrongEncodingError: - errorStatus, errorIndex = 'wrongEncoding', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.WrongValueError: - errorStatus, errorIndex = 'wrongValue', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.NoCreationError: - errorStatus, errorIndex = 'noCreation', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.InconsistentValueError: - errorStatus, errorIndex = 'inconsistentValue', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.ResourceUnavailableError: - errorStatus, errorIndex = 'resourceUnavailable', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.CommitFailedError: - errorStatus, errorIndex = 'commitFailed', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.UndoFailedError: - errorStatus, errorIndex = 'undoFailed', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.AuthorizationError: - errorStatus, errorIndex = 'authorizationError', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.NotWritableError: - errorStatus, errorIndex = 'notWritable', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.InconsistentNameError: - errorStatus, errorIndex = 'inconsistentName', sys.exc_info()[1]['idx'] + 1 - except pysnmp.smi.error.SmiError: - errorStatus, errorIndex = 'genErr', len(varBinds) and 1 or 0 - except pysnmp.error.PySnmpError: - self.releaseStateInformation(stateReference) - return - else: # successful request processor must release state info - return - - self.sendVarBinds(snmpEngine, stateReference, errorStatus, - errorIndex, varBinds) - - self.releaseStateInformation(stateReference) + self.initiateMgmtOperation(snmpEngine, stateReference, contextName, PDU) @classmethod def verifyAccess(cls, viewType, varBind, **context): @@ -258,21 +218,86 @@ class CommandResponderBase(object): # This will cause MibTree to skip this OID-value raise pysnmp.smi.error.NoAccessError(name=name, idx=context.get('idx')) + def _getMgmtFun(self, contextName): + return lambda *args, **kwargs: None -class GetCommandResponder(CommandResponderBase): - pduTypes = (rfc1905.GetRequestPDU.tagSet,) + def _checkSmiErrors(self, varBinds): + errorIndication = None + errorStatus = errorIndex = 0 + + exception = None + + for idx, varBind in enumerate(varBinds): + name, value = varBind + if isinstance(value, tuple): # expect exception tuple + debug.logger & debug.flagApp and debug.logger( + '_checkSmiErrors: exception reported for OID %s exception %s' % (name, value)) + + if not exception: + exception = value + + # reset exception object + varBinds[idx] = name, v2c.null + + try: + # TODO: perhaps chain exceptions + if exception: + debug.logger & debug.flagApp and debug.logger( + '_checkSmiErrors: re-raising exception %s' % (exception,)) + raise exception[1].with_traceback(exception[2]) + + # SNMPv2 SMI exceptions + except pysnmp.smi.error.GenError: + errorIndication = sys.exc_info()[1] + debug.logger & debug.flagApp and debug.logger( + '_checkSmiErrors: errorIndication %s' % (errorIndication,)) + + except pysnmp.smi.error.SmiError: + exc_type, exc_obj, trb = sys.exc_info() + + errorStatus = self.SMI_ERROR_MAP.get(exc_type, 'genErr') + + try: + errorIndex = exc_obj['idx'] + 1 + + except IndexError: + errorIndex = len(varBinds) and 1 or 0 + + return errorIndication, errorStatus, errorIndex def completeMgmtOperation(self, varBinds, **context): - self.sendVarBinds(context['snmpEngine'], context['stateReference'], - 0, 0, varBinds) - self.releaseStateInformation(context['stateReference']) - # rfc1905: 4.2.1 + try: + (errorIndication, + errorStatus, errorIndex) = self._checkSmiErrors(varBinds) + + except pysnmp.error.PySnmpError: + self.releaseStateInformation(context['stateReference']) + return + + stateReference = context['stateReference'] + + if errorIndication: + statusInformation = self.__pendingReqs[stateReference]['statusInformation'] + + try: + # Request REPORT generation + statusInformation['oid'] = errorIndication['oid'] + statusInformation['val'] = errorIndication['val'] + + except KeyError: + pass + + self.sendVarBinds(context['snmpEngine'], stateReference, + errorStatus, errorIndex, varBinds) + + self.releaseStateInformation(stateReference) + def initiateMgmtOperation(self, snmpEngine, stateReference, contextName, PDU): - # rfc1905: 4.2.1.1 - mgmtFun = self.snmpContext.getMibInstrum(contextName).readVars varBinds = v2c.apiPDU.getVarBinds(PDU) + mgmtFun = self._getMgmtFun(contextName) + context = dict(snmpEngine=snmpEngine, stateReference=stateReference, acFun=self.verifyAccess, @@ -282,56 +307,54 @@ class GetCommandResponder(CommandResponderBase): mgmtFun(*varBinds, **context) +class GetCommandResponder(CommandResponderBase): + SUPPORTED_PDU_TYPES = (rfc1905.GetRequestPDU.tagSet,) + + # rfc1905: 4.2.1 + def _getMgmtFun(self, contextName): + return self.snmpContext.getMibInstrum(contextName).readVars + + class NextCommandResponder(CommandResponderBase): - pduTypes = (rfc1905.GetNextRequestPDU.tagSet,) - - def completeMgmtOperation(self, varBinds, **context): - self.sendVarBinds(context['snmpEngine'], context['stateReference'], - 0, 0, varBinds) - self.releaseStateInformation(context['stateReference']) + SUPPORTED_PDU_TYPES = (rfc1905.GetNextRequestPDU.tagSet,) # rfc1905: 4.2.2 - def initiateMgmtOperation(self, snmpEngine, stateReference, contextName, PDU): - # rfc1905: 4.2.2.1 - mgmtFun = self.snmpContext.getMibInstrum(contextName).readNextVars - - varBinds = v2c.apiPDU.getVarBinds(PDU) - - context = dict(snmpEngine=snmpEngine, - stateReference=stateReference, - acFun=self.verifyAccess, - cbFun=self.completeMgmtOperation, - cbCtx=self.cbCtx) - - mgmtFun(*varBinds, **context) + def _getMgmtFun(self, contextName): + return self.snmpContext.getMibInstrum(contextName).readNextVars class BulkCommandResponder(CommandResponderBase): - pduTypes = (rfc1905.GetBulkRequestPDU.tagSet,) + SUPPORTED_PDU_TYPES = (rfc1905.GetBulkRequestPDU.tagSet,) maxVarBinds = 64 + def _getMgmtFun(self, contextName): + return self.snmpContext.getMibInstrum(contextName).readNextVars + def _completeNonRepeaters(self, varBinds, **context): context['rspVarBinds'][:] = varBinds - context['cbFun'] = self.completeMgmtOperation - mgmtFun = self.snmpContext.getMibInstrum(context['contextName']).readNextVars + if context['counters']['M'] and context['counters']['R']: + context['cbFun'] = self.completeMgmtOperation - mgmtFun(*context['varBinds'], **context) + mgmtFun = self._getMgmtFun(context['contextName']) + + mgmtFun(*context['reqVarBinds'], **context) + + else: + CommandResponderBase.completeMgmtOperation(self, context['rspVarBinds'], **context) def completeMgmtOperation(self, varBinds, **context): context['rspVarBinds'].extend(varBinds) context['counters']['M'] -= 1 if context['counters']['M'] and context['counters']['R']: - mgmtFun = self.snmpContext.getMibInstrum(context['contextName']).readNextVars + mgmtFun = self._getMgmtFun(context['contextName']) context['cbFun'] = self.completeMgmtOperation mgmtFun(*varBinds[-context['counters']['R']:], **context) else: - self.sendVarBinds(context['snmpEngine'], context['stateReference'], - 0, 0, varBinds) - self.releaseStateInformation(context['stateReference']) + CommandResponderBase.completeMgmtOperation(self, context['rspVarBinds'], **context) # rfc1905: 4.2.3 def initiateMgmtOperation(self, snmpEngine, stateReference, contextName, PDU): @@ -355,7 +378,7 @@ class BulkCommandResponder(CommandResponderBase): debug.logger & debug.flagApp and debug.logger( 'initiateMgmtOperation: N %d, M %d, R %d' % (N, M, R)) - mgmtFun = self.snmpContext.getMibInstrum(contextName).readNextVars + mgmtFun = self._getMgmtFun(contextName) context = dict(snmpEngine=snmpEngine, stateReference=stateReference, @@ -363,7 +386,7 @@ class BulkCommandResponder(CommandResponderBase): acFun=self.verifyAccess, cbFun=self._completeNonRepeaters, cbCtx=self.cbCtx, - varBinds=varBinds[-R:], + reqVarBinds=varBinds[N:], counters={'M': M, 'R': R}, rspVarBinds=[]) @@ -371,32 +394,14 @@ class BulkCommandResponder(CommandResponderBase): class SetCommandResponder(CommandResponderBase): - pduTypes = (rfc1905.SetRequestPDU.tagSet,) + SUPPORTED_PDU_TYPES = (rfc1905.SetRequestPDU.tagSet,) - def completeMgmtOperation(self, varBinds, **context): - self.sendVarBinds(context['snmpEngine'], context['stateReference'], - 0, 0, varBinds) - self.releaseStateInformation(context['stateReference']) + SMI_ERROR_MAP = CommandResponderBase.SMI_ERROR_MAP.copy() - # rfc1905: 4.2.5 - def initiateMgmtOperation(self, snmpEngine, stateReference, contextName, PDU): - mgmtFun = self.snmpContext.getMibInstrum(contextName).writeVars + # turn missing OIDs into access denial + SMI_ERROR_MAP[pysnmp.smi.error.NoSuchObjectError] = 'notWritable' + SMI_ERROR_MAP[pysnmp.smi.error.NoSuchInstanceError] = 'notWritable' - varBinds = v2c.apiPDU.getVarBinds(PDU) - - context = dict(snmpEngine=snmpEngine, - stateReference=stateReference, - acFun=self.verifyAccess, - cbFun=self.completeMgmtOperation, - cbCtx=self.cbCtx) - - # rfc1905: 4.2.5.1-13 - try: - mgmtFun(*varBinds, **context) - - except (pysnmp.smi.error.NoSuchObjectError, - pysnmp.smi.error.NoSuchInstanceError): - instrumError = pysnmp.smi.error.NotWritableError() - instrumError.update(sys.exc_info()[1]) - self.releaseStateInformation(stateReference) - raise instrumError + # rfc1905: 4.2.5.1-13 + def _getMgmtFun(self, contextName): + return self.snmpContext.getMibInstrum(contextName).writeVars diff --git a/pysnmp/entity/rfc3413/ntfrcv.py b/pysnmp/entity/rfc3413/ntfrcv.py index 34192ad3..df394a0c 100644 --- a/pysnmp/entity/rfc3413/ntfrcv.py +++ b/pysnmp/entity/rfc3413/ntfrcv.py @@ -14,12 +14,12 @@ from pysnmp import debug # 3.4 class NotificationReceiver(object): - pduTypes = (v1.TrapPDU.tagSet, v2c.SNMPv2TrapPDU.tagSet, - v2c.InformRequestPDU.tagSet) + SUPPORTED_PDU_TYPES = (v1.TrapPDU.tagSet, v2c.SNMPv2TrapPDU.tagSet, + v2c.InformRequestPDU.tagSet) def __init__(self, snmpEngine, cbFun, cbCtx=None): snmpEngine.msgAndPduDsp.registerContextEngineId( - null, self.pduTypes, self.processPdu # '' is a wildcard + null, self.SUPPORTED_PDU_TYPES, self.processPdu # '' is a wildcard ) self.__snmpTrapCommunity = '' @@ -33,7 +33,7 @@ class NotificationReceiver(object): def close(self, snmpEngine): snmpEngine.msgAndPduDsp.unregisterContextEngineId( - null, self.pduTypes + null, self.SUPPORTED_PDU_TYPES ) self.__cbFun = self.__cbCtx = None diff --git a/pysnmp/smi/instrum.py b/pysnmp/smi/instrum.py index d84493ac..cec737d6 100644 --- a/pysnmp/smi/instrum.py +++ b/pysnmp/smi/instrum.py @@ -6,6 +6,8 @@ # import sys import traceback +import functools +from pysnmp import nextid from pysnmp.smi import error from pysnmp import debug @@ -24,39 +26,59 @@ class AbstractMibInstrumController(object): class MibInstrumController(AbstractMibInstrumController): + STATUS_OK = 'ok' + STATUS_ERROR = 'err' + + STATE_START = 'start' + STATE_STOP = 'stop' + STATE_ANY = '*' + # These states are actually methods of the MIB objects + STATE_READ_TEST = 'readTest' + STATE_READ_GET = 'readGet' + STATE_READ_TEST_NEXT = 'readTestNext' + STATE_READ_GET_NEXT = 'readGetNext' + STATE_WRITE_TEST = 'writeTest' + STATE_WRITE_COMMIT = 'writeCommit' + STATE_WRITE_CLEANUP = 'writeCleanup' + STATE_WRITE_UNDO = 'writeUndo' + fsmReadVar = { # ( state, status ) -> newState - ('start', 'ok'): 'readTest', - ('readTest', 'ok'): 'readGet', - ('readGet', 'ok'): 'stop', - ('*', 'err'): 'stop' + (STATE_START, STATUS_OK): STATE_READ_TEST, + (STATE_READ_TEST, STATUS_OK): STATE_READ_GET, + (STATE_READ_GET, STATUS_OK): STATE_STOP, + (STATE_ANY, STATUS_ERROR): STATE_STOP } fsmReadNextVar = { # ( state, status ) -> newState - ('start', 'ok'): 'readTestNext', - ('readTestNext', 'ok'): 'readGetNext', - ('readGetNext', 'ok'): 'stop', - ('*', 'err'): 'stop' + (STATE_START, STATUS_OK): STATE_READ_TEST_NEXT, + (STATE_READ_TEST_NEXT, STATUS_OK): STATE_READ_GET_NEXT, + (STATE_READ_GET_NEXT, STATUS_OK): STATE_STOP, + (STATE_ANY, STATUS_ERROR): STATE_STOP } fsmWriteVar = { # ( state, status ) -> newState - ('start', 'ok'): 'writeTest', - ('writeTest', 'ok'): 'writeCommit', - ('writeCommit', 'ok'): 'writeCleanup', - ('writeCleanup', 'ok'): 'readTest', + (STATE_START, STATUS_OK): STATE_WRITE_TEST, + (STATE_WRITE_TEST, STATUS_OK): STATE_WRITE_COMMIT, + (STATE_WRITE_COMMIT, STATUS_OK): STATE_WRITE_CLEANUP, + (STATE_WRITE_CLEANUP, STATUS_OK): STATE_READ_TEST, # Do read after successful write - ('readTest', 'ok'): 'readGet', - ('readGet', 'ok'): 'stop', + (STATE_READ_TEST, STATUS_OK): STATE_READ_GET, + (STATE_READ_GET, STATUS_OK): STATE_STOP, # Error handling - ('writeTest', 'err'): 'writeCleanup', - ('writeCommit', 'err'): 'writeUndo', - ('writeUndo', 'ok'): 'readTest', + (STATE_WRITE_TEST, STATUS_ERROR): STATE_WRITE_CLEANUP, + (STATE_WRITE_COMMIT, STATUS_ERROR): STATE_WRITE_UNDO, + (STATE_WRITE_UNDO, STATUS_OK): STATE_READ_TEST, # Ignore read errors (removed columns) - ('readTest', 'err'): 'stop', - ('readGet', 'err'): 'stop', - ('*', 'err'): 'stop' + (STATE_READ_TEST, STATUS_ERROR): STATE_STOP, + (STATE_READ_GET, STATUS_ERROR): STATE_STOP, + (STATE_ANY, STATUS_ERROR): STATE_STOP } + FSM_CONTEXT = '_fsmContext' + + FSM_SESSION_ID = nextid.Integer(0xffffffff) + def __init__(self, mibBuilder): self.mibBuilder = mibBuilder self.lastBuildId = -1 @@ -183,88 +205,115 @@ class MibInstrumController(AbstractMibInstrumController): # MIB instrumentation - def flipFlopFsm(self, fsmTable, *varBinds, **context): + def _flipFlopFsmCb(self, varBind, **context): + fsmContext = context[self.FSM_CONTEXT] + varBinds = fsmContext['varBinds'] + + idx = context.pop('idx') + + if idx >= 0: + fsmContext['count'] += 1 + + varBinds[idx] = varBind + + debug.logger & debug.flagIns and debug.logger( + '_flipFlopFsmCb: var-bind %d, processed %d, expected %d' % (idx, fsmContext['count'], len(varBinds))) + + if fsmContext['count'] < len(varBinds): + return + + debug.logger & debug.flagIns and debug.logger( + '_flipFlopFsmCb: finished, output %r' % (varBinds,)) + + fsmCallable = fsmContext['fsmCallable'] + + fsmCallable(**context) + + def flipFlopFsm(self, fsmTable, *varBinds, **context): try: - fsmContext = context['fsmState'] + fsmContext = context[self.FSM_CONTEXT] except KeyError: self.__indexMib() - fsmContext = context['fsmState'] = dict(varBinds=[], state='start', status='ok') + fsmContext = context[self.FSM_CONTEXT] = dict( + sessionId=self.FSM_SESSION_ID(), + varBinds=list(varBinds[:]), + fsmCallable=functools.partial(self.flipFlopFsm, fsmTable, *varBinds), + state=self.STATE_START, status=self.STATUS_OK + ) debug.logger & debug.flagIns and debug.logger('flipFlopFsm: input var-binds %r' % (varBinds,)) mibTree, = self.mibBuilder.importSymbols('SNMPv2-SMI', 'iso') - outputVarBinds = fsmContext['varBinds'] state = fsmContext['state'] status = fsmContext['status'] - origExc = origTraceback = None + debug.logger & debug.flagIns and debug.logger( + 'flipFlopFsm: current state %s, status %s' % (state, status)) + + try: + newState = fsmTable[(state, status)] + + except KeyError: + try: + newState = fsmTable[(self.STATE_ANY, status)] + + except KeyError: + raise error.SmiError('Unresolved FSM state %s, %s' % (state, status)) + + debug.logger & debug.flagIns and debug.logger( + 'flipFlopFsm: state %s status %s -> new state %s' % (state, status, newState)) + + state = newState + + if state == self.STATE_STOP: + context.pop(self.FSM_CONTEXT, None) + + cbFun = context.get('cbFun') + if cbFun: + varBinds = fsmContext['varBinds'] + cbFun(varBinds, **context) + + return + + fsmContext.update(state=state, count=0) + + # the case of no var-binds + if not varBinds: + return self._flipFlopFsmCb(None, idx=-1, **context) + + mgmtFun = getattr(mibTree, state, None) + if not mgmtFun: + raise error.SmiError( + 'Unsupported state handler %s at %s' % (state, self) + ) + + for idx, varBind in enumerate(varBinds): + try: + # TODO: managed objects to run asynchronously + #mgmtFun(varBind, idx=idx, **context) + self._flipFlopFsmCb(mgmtFun(varBind, idx=idx, **context), idx=idx, **context) + + except error.SmiError: + exc = sys.exc_info() + debug.logger & debug.flagIns and debug.logger( + 'flipFlopFsm: fun %s exception %s for %r with traceback: %s' % ( + mgmtFun, exc[0], varBind, traceback.format_exception(*exc))) + + varBind = varBind[0], exc + + fsmContext['status'] = self.STATUS_ERROR + + self._flipFlopFsmCb(varBind, idx=idx, **context) + + return - while True: - k = state, status - if k in fsmTable: - fsmState = fsmTable[k] else: - k = '*', status - if k in fsmTable: - fsmState = fsmTable[k] - else: - raise error.SmiError( - 'Unresolved FSM state %s, %s' % (state, status) - ) - debug.logger & debug.flagIns and debug.logger( - 'flipFlopFsm: state %s status %s -> fsmState %s' % (state, status, fsmState)) - state = fsmState - status = 'ok' - if state == 'stop': - break - - for idx, (name, val) in enumerate(varBinds): - mgmtFun = getattr(mibTree, state, None) - if not mgmtFun: - raise error.SmiError( - 'Unsupported state handler %s at %s' % (state, self) - ) - - context['idx'] = idx - - try: - # Convert to tuple to avoid ObjectName instantiation - # on subscription - rval = mgmtFun((tuple(name), val), **context) - - except error.SmiError: - exc_t, exc_v, exc_tb = sys.exc_info() - debug.logger & debug.flagIns and debug.logger( - 'flipFlopFsm: fun %s exception %s for %s=%r with traceback: %s' % ( - mgmtFun, exc_t, name, val, traceback.format_exception(exc_t, exc_v, exc_tb))) - if origExc is None: # Take the first exception - origExc, origTraceback = exc_v, exc_tb - status = 'err' - break - else: - debug.logger & debug.flagIns and debug.logger( - 'flipFlopFsm: fun %s succeeded for %s=%r' % (mgmtFun, name, val)) - if rval is not None: - outputVarBinds.append((rval[0], rval[1])) - - if origExc: - if sys.version_info[0] <= 2: - raise origExc - else: - try: - raise origExc.with_traceback(origTraceback) - finally: - # Break cycle between locals and traceback object - # (seems to be irrelevant on Py3 but just in case) - del origTraceback - - cbFun = context.get('cbFun') - if cbFun: - cbFun(outputVarBinds, **context) + debug.logger & debug.flagIns and debug.logger( + 'flipFlopFsm: func %s initiated for %r' % (mgmtFun, varBind)) def readVars(self, *varBinds, **context): self.flipFlopFsm(self.fsmReadVar, *varBinds, **context)