I had a hard time finding documentation, and what I did find was old and outdated. I figured most of it out just by playing around with the library.
#!/usr/bin/env python
import netsnmp
string = 'public'
ver = 1
port = 161
host = '192.168.1.1'
# uptime using method 1
bind1 = netsnmp.Varbind('sysUpTime.0')
# 1 minute load using method 2
bind2 = netsnmp.Varbind('.1.3.6.1.4.1.2021.10.1.3.1')
snmpget = netsnmp.snmpget(bind1,
Version=ver,
RemotePort=port,
DestHost=host,
Community=string)
uptime_seconds = snmpget[0]
print uptime_seconds
list = ( bind1, bind2 )
x = netsnmp.Session(DestHost=host,
Version=ver,
RemotePort=port,
Timeout=400000,
Retries=5,
Community=string)
output_list = x.get(list)
if not output_list:
print "FAILED TO CONNECT!!!"
sys.exit(1)
if output_list[0]:
uptime = output_list[0]
if output_list[1]:
load1 = output_list[1]

I replaced the bottom gnome-panel with this. If you remove everything except the Launcher/Taskmanager applet and add the Show Desktop applet, it directly replaces gnome-panels functionality completely.