Hi everyone,
I’m debugging an issue with returning strings from OIDs wich are wrapped in double quotes.
First things first.
Telegraf Version: 1.27.4 with influxdb2
This is my snmp target config
# CW1
[[inputs.snmp]]
## Agent addresses to retrieve values from.
agents = ["192.168.204.3:161"]
## Timeout for each request.
timeout = "5s"
version = 2
community = "stats"
[[inputs.snmp.field]]
name = "SysName"
oid = "1.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4329"
is_tag = true
[[inputs.snmp.field]]
oid = "1.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4123"
name = "chillerstatus"
[[inputs.snmp.field]]
oid = "1.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.5078"
name = "Compressor Utilization"
conversion="float"
[[processors.strings]]
## Trim leading characters in cutset
[[processors.strings.trim_left]]
field = "chillerstatus"
cutset = "\""
## Trim trailing characters in cutset
[[processors.strings.trim_right]]
field = "chillerstatus"
cutset = "\""
[[inputs.exec]]
command = "/opt/scripts/remove-quotes.sh"
data_format = "influx"
As you can see I already tried using string trim.
I also used regex before and even external scripts to remove double quotes.
The thing is, if I set the cutset to “N” instead of “"” it cuts the first letter as exptected.
This is the output from snmpwalk (same with snmpget)
root@grafana-dc:~# snmpwalk -v2c -c stats 192.168.204.3 1.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4123
iso.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4123 = STRING: “Normal with Warning”
root@grafana-dc:~# snmpget -v2c -c stats 192.168.204.3 1.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4123
iso.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4123 = STRING: “Normal with Warning”
I got a ton of strings to handle wich are all wrapped in double quotes and as far as I understand the code correctly, the double quotes should be removed here:
if conv == "" {
// Handle cases where no conversion is specified (e.g., default string handling).
// If the SNMP value is []byte, it's converted to a string.
if bs, ok := ent.Value.([]byte); ok {
return string(bs), nil
}
return ent.Value, nil
}
But somehow they are still present.
Futhermore they even get preserved!
I also configured an external script as an input (as you can see in my config above)
This script does it simply:
#!/bin/bash
# Run snmpwalk and format output as InfluxDB line protocol
output=$(snmpwalk -v2c -c stats 192.168.204.3 1.3.6.1.4.1.476.1.42.3.9.20.1.20.1.2.1.4123 | awk -F': ' '{gsub(/"/, "", $2); gsub(/ /, "_", $2); print "snmp chillerstatus=\"" $2 "\""}')
# Print output
echo "$output"
And even then the double quotes are still present.
This is the output from the test run:
root@grafana-dc:~# telegraf --test | grep snmp
2023-08-31T07:27:34Z I! Loading config: /etc/telegraf/telegraf.conf
2023-08-31T07:27:34Z I! Starting Telegraf 1.27.4
2023-08-31T07:27:34Z I! Available plugins: 237 inputs, 9 aggregators, 28 processors, 23 parsers, 59 outputs, 4 secret-stores
2023-08-31T07:27:34Z I! Loaded inputs: cpu disk diskio ethtool exec ipmi_sensor ipset kernel mem processes snmp (7x) swap system
2023-08-31T07:27:34Z I! Loaded aggregators:
2023-08-31T07:27:34Z I! Loaded processors: strings
2023-08-31T07:27:34Z I! Loaded secretstores:
2023-08-31T07:27:34Z W! Outputs are not used in testing mode!
2023-08-31T07:27:34Z I! Tags enabled: host=grafana-dc
> snmp,SysName=environment-HV-USV,agent_host=192.168.104.25,host=grafana-dc HV-USV\ -\ Humidity=39.9,HV-USV\ -\ Temperatur=24.2 1693466855000000000
> snmp,host=grafana-dc chillerstatus="Normal_with_Warning" 1693466855000000000
> snmp,SysName=CW\ 1,agent_host=192.168.204.3,host=grafana-dc Compressor\ Utilization=25,chillerstatus="Normal with Warning" 1693466855000000000
> snmp,SysName=sensor2,agent_host=192.168.201.51,host=grafana-dc A.C5\ -\ Raised\ Floor\ Humidity=61,A.C5\ -\ Raised\ Floor\ Temp=17 1693466855000000000
> snmp,SysName=sensor3,agent_host=192.168.201.52,host=grafana-dc A.Q1\ -\ Raised\ Floor\ Temp=17.5,A.T2\ -\ Raised\ Floor\ Temp=16.6 1693466855000000000
> snmp,SysName=sensor1,agent_host=192.168.201.50,host=grafana-dc Routing\ -\ Raised\ Floor\ Temp=17.3,Routing\ -\ Room\ Temp=26.5 1693466855000000000
> snmp,SysName=Sensor-Raum-C,agent_host=192.168.201.53,host=grafana-dc Raum\ C\ -\ Raised\ Floor\ Temp=17.3,Raum\ C\ -\ Room\ Temp=25.1 1693466855000000000
> snmp,SysName=environment-sensor-NSHV,agent_host=192.168.104.26,host=grafana-dc NSHV\ -\ Humidity=48.6,NSHV\ -\ Temperatur=23.4 1693466855000000000
In both approaches with trims or with external script the double quotes are still present and as a result not parsed to influx.
Is there any workaround I can build to address this issue?
Any help would be much appreciated.
