Telegraf unable to pull route table information from Arista MIB - snmp

Question

So I'm trying to collect routing stats from some Aristas.
When I run snmpwalk it all seems to work...
snmpwalk -v2c -c pub router.host ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.other = Gauge32: 3
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.connected = Gauge32: 8
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.static = Gauge32: 26
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.ospf = Gauge32: 542
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.bgp = Gauge32: 1623
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.attached = Gauge32: 12
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv4.internal = Gauge32: 25
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv6.other = Gauge32: 3
ARISTA-FIB-STATS-MIB::aristaFIBStatsTotalRoutesForRouteType.ipv6.internal = Gauge32: 1
But when I try to pull the stats with telegraf I get different information with missing context...
BGP,agent_host=10.45.100.20,host=nw01.ny5,hostname=CR.NY aristaFIBStatsTotalRoutesForRouteType=2i 1654976575000000000
BGP,agent_host=10.45.100.20,host=nw01.ny5,hostname=CR.NY aristaFIBStatsTotalRoutes=2260i 1654976575000000000
BGP,agent_host=10.45.100.20,host=nw01.ny5,hostname=CR.NY aristaFIBStatsTotalRoutesForRouteType=8i 1654976575000000000
BGP,agent_host=10.45.100.20,host=nw01.ny5,hostname=CR.NY aristaFIBStatsTotalRoutesForRouteType=63i 1654976575000000000
According to the MIB documentation..
https://www.arista.com/assets/data/docs/MIBS/ARISTA-FIB-STATS-MIB.txt
it is using IANA-RTPROTO-MIB.txt protocol definitions but I have no idea where to derive that information from as the retrieved data via telegraf isn't showing me anything. Anyone know how to deal with this?

Answer 1

First, you might want to enable telegraf to return the index of the returned rows by setting index_as_tag = true inside the inputs.snmp.table.
Then, add the following processors in your config:
# Parse aristaFIBStatsAF and aristaFIBStatsRouteType from index for BGP table
[[processors.regex]]
namepass = ["BGP"]
order = 1
[[processors.regex.tags]]
## Tag to change
key = "index"
## Regular expression to match on a tag value
pattern = "^(\\d+)\\.(\\d+)$"
replacement = "${1}"
## Tag to store the result
result_key = "aristaFIBStatsAF"
[[processors.regex.tags]]
## Tag to change
key = "index"
## Regular expression to match on a tag value
pattern = "^(\\d+)\\.(\\d+)$"
replacement = "${2}"
## Tag to store the result
result_key = "aristaFIBStatsRouteType"
# Rename index to aristaFIBStatsAF for BGP table with single index row
[[processors.rename]]
namepass = ["BGP"]
order = 2
[[processors.rename.replace]]
tag = "index"
dest = "aristaFIBStatsAF"
[processors.rename.tagdrop]
aristaFIBStatsAF = ["*"]
# Translate tag values for BGP table
[[processors.enum]]
namepass = ["BGP"]
order = 3
tagexclude = ["index"]
[[processors.enum.mapping]]
## Name of the tag to map
tag = "aristaFIBStatsAF"
## Table of mappings
[processors.enum.mapping.value_mappings]
0 = "unknown"
1 = "ipv4"
2 = "ipv6"
[[processors.enum.mapping]]
## Name of the tag to map
tag = "aristaFIBStatsRouteType"
## Table of mappings
[processors.enum.mapping.value_mappings]
1 = "other"
2 = "connected"
3 = "static"
8 = "rip"
9 = "isIs"
13 = "ospf"
14 = "bgp"
200 = "ospfv3"
201 = "staticNonPersistent"
202 = "staticNexthopGroup"
203 = "attached"
204 = "vcs"
205 = "internal"
Disclaimer: did not test this in telegraf, so there might be some typo's