SNMP is not really simple (PySNMP implementation takes over 15K lines of Python code), but PySNMP tries to isolate the complexities and let you perform typical SNMP operations in a quick and intuitive way.
PySNMP offers three groups of programming interfaces to deal with SNMP protocol. In the order from most consice to most detailed those APIs follow.
The so called high-level API (hlapi) is designed to be simple, concise and suitable for the most frequent operations. For that matter only Command Generator and Notification Originator Applications are currently wrapped into a nearly one-line Python expression.
It comes in several flavours: one synchronous and a bunch of bindings to popular asynchronous I/O frameworks. Those varieties of APIs bring subtile differences, mostly to better match particular I/O framework customs. Unless you have a vary specific task, one of high-level APIs might solve your SNMP needs.
Native SNMP API¶
Complete implementation of all official Standard SNMP Applications. It should let you implement any SNMP operation defined in the standard at the cost of working at a somewhat low level.
This API also comes in several transport varieties depending on I/O framework being used.
- Asynchronous: asyncore
- Asynchronous: asyncio
- Asynchronous: trollius
- Asynchronous: Twisted
In cases where performance is your top priority and you only need to work with SNMP v1 and v2c systems and you do not mind writing much more code, then there is a low-level API to SNMP v1/v2c PDU and PySNMP I/O engine. There’s practically no SNMP engine or SMI infrastructure involved in the operations of these almost wire-level interfaces. Although MIB services can still be used separately.
A packet-level API-based application typically manages both SNMP message building/parsing and network communication via one or more transports. It’s fully up to the application to handle failures on message and transport levels.
Low-level MIB access¶
Using these examples¶
Before doing cut&paste of the code below into your Python interpreter, make sure to install pysnmp and its dependencies by running pip or easy_install:
# pip pysnmp
There’s a public, multilingual SNMP Command Responder and Notification Receiver configured at demo.snmplabs.com to let you run PySNMP examples scripts in a cut&paste fashion. If you wish to use your own SNMP Agent with these scripts, make sure to either configure your local snmpd and/or snmptrapd or use a valid address and SNMP credentials of your SNMP Agent in the examples to let them work.
Should you want to use a MIB to make SNMP operations more human-friendly, you are welcome to search for it and possibly download one from our public MIB repository. Alternatively, you can configure PySNMP to fetch and cache required MIBs from there automatically.
If you find your PySNMP application behaving unexpectedly, try to enable a /more or less verbose/ built-in PySNMP debugging by adding the following snippet of code at the beginning of your application:
from pysnmp import debug # use specific flags or 'all' for full debugging debug.setLogger(debug.Debug('dsp', 'msgproc', 'secmode'))
Then run your app and watch stderr. The Debug initializer enables debugging for a particular PySNMP subsystem, ‘all’ enables full debugging. More specific flags are:
For more details on PySNMP programming model and interfaces, please refer to library documentation.