TwistedSNMP

TwistedSNMP is a set of SNMP protocol implementations for Python's Twisted Matrix networking framework using the PySNMP project.  It provides the following:

• get, set, getnext and getbulk Manager-side queries
• get, set, getnext and getbulk Agent-side services

Eventual goals of the system:

• provide access to all v1 and v2 SNMP functionality for writing Agent and Manager services
• provide convenient testing mechanisms for SNMP Agent/Manager development (e.g. mirroring an SNMP Agent's OID tree for local query testing)

Once complete, we can look at either incorporating the system into the PySNMP or Twisted distribution.  For now, you can download TwistedSNMP from the project page.

Installation

TwistedSNMP is distributed as a Python distutils package.  You can install it by unpacking the source distribution and running:

In the top level of the install directory.  You will need both Twisted and PySNMP 3.x installed

Documentation

At the moment, most of the documentation for the module is in the form of the auto-generated PyDoc reference API, which includes auto-generated documentation for PySNMP.  You can find usage examples in the test sub-directory of the distribution.

Changes

Version 0.2.10

• Rewrite table-retrieval results-handling to be more robust and simple
  

Version 0.2.9

• Catch socket errors during message sending and report as Twisted failures (otherwise the errors simply print exceptions and are ignored, which can hang client code that expects (rightly) an eventual return value from something which calls a TwistedSNMP method).
  

Version 0.2.8

• BSDOIDStore.close method added to actually save data to disk (useful, that :) )
• Modifications to MirrorAgent to call close on OID store
• Bug-fixes in both OIDStore classes (old BSDDB data-files will be incompatible as a result)
• Essentially, the OIDs were being stored in too naive an order, so the oid 0.1.2 would sort after 0.1.12, i.e. using simple string sorting
• BisectOIDStore now uses a tuple of integers while BSDOIDStore uses a packed binary string representation
  

Version 0.2.7

• Refactoring of Agent class to allow for easier construction of mock objects that can simulate agent dialogues without needing to go through the SNMP encoding/decoding stages
• Introduction of stand-alone errors module
• Use of errors module in OIDStore classes to indicate failed OID lookup
  

Version 0.2.6

• Mostly just documentation changes to reflect new project location URLs and the like.
  

Version 0.2.5

• Altered timeout methods to catch exceptions within themselves and relay to the caller via the registered deferred object
• Documentation enhancements
• Patch to work around Python 2.3.x bug in the BSDDB wrapper class
• Eliminated old algorithms for MassRetriever
• Reduced default MassRetriever iteration delay to 0.005 instead of 0.01 seconds
  

Version 0.2.4

• Fixed bug with table request processing.
  

Version 0.2.3

• Rework of mass retriever algorithm (yet again) to be more robust when dealing with larger AgentProxy sets
• Much simpler mechanism
• Throttles to initiate less than 200 queries/second by default, but ignores the number in play, which, as it turns out, seems to be somewhat useless for managing load.  This is not ideal, as, at least on our testing systems, the hardware can readily handle a few thousand queries/second (it's Twisted's structure that requires the throttling).
  
• Internal rework so that timeouts are cancelled ASAP for messages received
• To prevent timeouts issuing before the system gets around to calling the callback
• Discovered (as-yet-unfixed) bug in Agent's (as distinct from AgentProxy) processing of table requests
• Basically it doesn't properly handle tables of different lengths.
  

Version 0.2.2

• Bug-fix in utilities/mirroragent.py
  
• Test module cleanup for cross-platform operation
  
• Allow for operation when no bsddb module is available, as there are platforms on which it's not available by default
• Use non-privileged port if the privileged 161 is not bindable
  
• Added check to twineTables for NULL OID set (passing in such an OID set makes no sense, and would cause silent, difficult-to-track-down errors)
  

Version 0.2.1

• Cleaned up and reworked mass-query mechanism;
• patterned loosely after the table-query mechanism
  
• fixed at least one logic bug in the batching machinery
  
• added adaptive heuristics for determining number of queries to keep in play
• changes the api for retrieval in a backward-incompatible way
  
• Fixed shallow bug in TableRetriever's handling of responses with unequal rootOID and (OID,value) set lengths
  

Version 0.2.0

• Complete refactoring of the client/manager-side API.  Instead of requiring one port per managed agent, is able to manage any number of agents from a single port. Most of the machinery of the old protocol object is now part of an AgentProxy class.  You *will* need to modify all client code to work with the new API.  Mostly just a matter of a different initialisation pattern and then using the AgentProxy object in the same manner as you used the old SNMPProtocol object.
• Crude mass-query mechanism created.  As of yet only tested against a local server, and doesn't yet have balancing heuristics to throttle load in response to network response, but does appear to work.
  
• Dropped the snmpports module.  It's no longer necessary with the new structure.
• Bug was discovered in Python 2.3's BSDDB module which affects the BSDDB storages, bug report submitted to the Python project, but for now, will not pass tests under Python 2.3.
  

Version 0.1.5

• Refactored the test-suite into its own package w/ sub-modules for the different test-types
• Fixed bug in usage of oidStore API for Agent set-requests
  

Version 0.1.4

• Utilities:
• mirroragent -- mirrors an agent to local bsddb shelve for testing (still very rough, just a sketch, really)
  
• BSDOIDStore -- a new OIDStore implementation for use in utilities
  
• Major refactoring of the Agent-side mechanisms:
• AgentProtocol -- low-level send and dispatch of messages to the Agent
• Agent -- SNMP logic for get/getNext/getTable/set implementation
• OIDStore -- interface for storage/retrieval of ordered OID tree
• BisectOIDStore -- the demo OIDStore implementation for testing purposes using the bisect module
  

Version 0.1.3

• Agent and Manager-side set protocol implementation
• Minimal sample code for Agent-side set code, doesn't yet do the error-negotiation stuff
  

Version 0.1.2

• Test code
  
• Agent-side protocol sample code extended to include getnext and getbulk
  

Version 0.1.1

• Beginning of work on an Agent-side protocol and some sample Agent code

Version 0.1

• Initial release
  

TwistedSNMP  is a Open-Source Project