HNMP is a high-level Python library to ease the pain of retrieving and processing data from SNMP-capable devices such as network switches, routers, and printers. It's not meant to provide everything SNMP has to offer, but to get rid of most of the suck inherent to writing Munin or Icinga plugins that process SNMP data.

HNMP is meant to be used like this:

1. acquire MIB files (optional, some luck required)
2. use a MIB browser application like this freeish and cross-platform one to figure out the numeric OIDs you're interested in
3. use HNMP to retrieve your data and do some light processing
4. put human on Mars 🚀

Usage

>>> from hnmp import SNMP
>>>
>>> snmp = SNMP("example.com", community="public")  # v2c
>>> snmp = SNMP(
...    "example.com",
...    version=3,
...    username="jdoe",
...    authproto="sha",
...    authkey="secret",
...    privproto="aes128",
...    privkey="secret",
... )  # v3

# get a single value
>>> uptime = snmp.get("1.3.6.1.2.1.1.3.0")
>>> uptime
datetime.timedelta(412, 29152)

# build a table from MIB AIRESPACE-WIRELESS-MIB::bsnMobileStationEntry.
>>> bsnMobileStationEntryOID = "1.3.6.1.4.1.14179.2.1.4.1"
>>> wifi_clients = snmp.table(
>>>     bsnMobileStationEntryOID,
>>>     columns={
>>>         3: "username",
>>>         25: "protocol",
>>>     },
>>>     column_value_mapping={
>>>         "protocol": {
>>>             3: "802.11g",
>>>             6: "802.11n",
>>>         },
>>>     },
>>>     fetch_all_columns=False,  # fetch only named columns (useful with large tables)
>>> )
>>>
>>> wifi_clients.columns["username"]
("jdoe", "rms", "bwayne")
>>> wifi_clients.columns["protocol"]
("802.11g", "802.11n", "802.11n")
>>> wifi_clients.rows[0]["username"]
"jdoe"

# conveniently count column values
>>> wifi_clients.columns["protocol"]
("802.11g", "802.11n", "802.11n")
>>> wifi_clients.columns["protocol"].value_count
{"802.11g": 1, "802.11n": 2}

# helpers for converting MAC and IP addresses
>>> from hnmp import ipv4_address, mac_address
>>> raw_string = snmp.get("1.3.6.1.4.1.9.9.513.1.1.1.1.2.[...]")
>>> raw_string
't&\xac\x1b\xe7\xa1'
>>> mac_address(raw_string)
'74:26:ac:1b:e7:a1'
>>> ipv4_address(snmp.get("1.3.6.1.4.1.9.9.513.1.1.1.1.11.[...]"))
'10.1.2.3'

# set a value
>>> snmp.set("1.2.3.4.5.6.7.8.9.0", "foobar")
>>> snmp.set("1.2.3.4.5.6.7.8.9.0", "10.1.2.3")  # IPv4 address is converted automatically
>>> snmp.set("1.2.3.4.5.6.7.8.9.0", 23, value_type='Counter64')  # use explicit type

Install

pip install hnmp

FAQ

How do the table OIDs work?

Quite often you will find that you need to query a whole table instead of a single value (e.g. a list of network interfaces). This is how the OIDs are organized in a table:

1.3.6.1.4.1.9.9.513.1.1.1.1.11.1.2.3.4.5
1.3.6.1.4.1.9.9.513.1.1.1.1.11.1.2.3.4.6
1.3.6.1.4.1.9.9.513.1.1.1.1.11.1.2.3.4.7
1.3.6.1.4.1.9.9.513.1.1.1.1.12.1.2.3.4.5
1.3.6.1.4.1.9.9.513.1.1.1.1.12.1.2.3.4.6
1.3.6.1.4.1.9.9.513.1.1.1.1.12.1.2.3.4.7
\_____________ ____________/|  \___ ___/
              │             │      |
              │             │    Row ID
              │             │
              │          Column ID
              │
           Base OID

Starting from the base OID (1.3.6.1.4.1.9.9.513.1.1.1.1 in this example), you will see the different column IDs (11 and 12 in this example) repeated for every row. Row IDs consist of everything after the column ID. Sometimes these are only sequential single digits, but they can also be made up of multiple numbers. In this example, there are three rows with IDs 1.2.3.4.5, 1.2.3.4.6, and 1.2.3.4.7.

Why doesn't HNMP support loading MIB files?

Depending on MIB files would make the calling piece of code harder to distribute (since you need to include the MIBs, which may have some nasty non-free license attached to them). I consider MIB files a means to manually discover OIDs, nothing more. HNMP is biased towards use in scripts rather than full-blown applications. Having to use a library is bad enough for scripts, MIBs would just make your script even more unwieldy.

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