inputs.statsd: Error in plugin: read udp [::]:8125: use of closed network connection

[passing]

Relevant telegraf.conf:

[[inputs.statsd]]

Steps to reproduce:

having placed logstash.conf in your working directory, execute:

docker run -ti -v $(pwd)/telegraf.conf:/etc/telegraf/telegraf.conf telegraf:1.18.3 --test

the run succeeds with the following output:

2021-10-06T13:27:24Z I! Starting Telegraf 1.18.3
2021-10-06T13:27:24Z I! Using config file: /etc/telegraf/telegraf.conf
2021-10-06T13:27:24Z I! [inputs.statsd] UDP listening on "[::]:8125"
2021-10-06T13:27:24Z I! [inputs.statsd] Started the statsd service on ":8125"
2021-10-06T13:27:24Z I! [inputs.statsd] Stopping the statsd service
2021-10-06T13:27:24Z I! [inputs.statsd] Stopped listener service on ":8125"

using any later version, doesn't:

docker run -ti -v $(pwd)/telegraf.conf:/etc/telegraf/telegraf.conf telegraf:1.19.3 --test
docker run -ti -v $(pwd)/telegraf.conf:/etc/telegraf/telegraf.conf telegraf:1.20.0 --test

the run fails with the following output:

2021-10-06T13:25:24Z I! Starting Telegraf 1.19.3
2021-10-06T13:25:24Z I! Using config file: /etc/telegraf/telegraf.conf
2021-10-06T13:25:24Z I! [inputs.statsd] UDP listening on "[::]:8125"
2021-10-06T13:25:24Z I! [inputs.statsd] Started the statsd service on ":8125"
2021-10-06T13:25:24Z I! [inputs.statsd] Stopping the statsd service
2021-10-06T13:25:24Z E! [inputs.statsd] Error in plugin: read udp [::]:8125: use of closed network connection
2021-10-06T13:25:24Z I! [inputs.statsd] Stopped listener service on ":8125"
2021-10-06T13:25:24Z E! [telegraf] Error running agent: input plugins recorded 1 errors

Expected behavior:

test run should exit successfully without any error

Actual behavior:

test run fails with error

[powersj]

Hi @passing,

Trying to run the statsd input in --test mode is not very useful. Are you only seeing this when using --test mode?

Thanks!

[passing]

Hi @powersj,

We only see this in --test mode which we use for automated tests for our telegraf deployment configuration: whenever changes are made in a repository, a build runs to verify that the configuration is valid. The --test mode seems to be the best way to do that, but due to the issue we cannot use it in any project that uses the inputs.statsd plugin.

[powersj]

whenever changes are made in a repository, a build runs to verify that the configuration is valid. The --test mode seems to be the best way to do that

Interesting, --test will essentially let you know if your inputs work and your TOML configs are parsable, but be aware it does not run outputs.

The reason for the error message is from this change where Telegraf started checking some additional errors.

Given we previously weren't checking for a closed network connection error in the first place, I think it is safe to make a small update where we return nil. I've put up PR #11043 with a possible workaround. Give it a shot!

[passing]

Thank you!
I just gave it a try using the PR build artifacts to patch our docker image:

ADD https://output.circle-artifacts.com/output/job/49cf6b94-b663-4f62-8a7a-34cd4cc32f3d/artifacts/0/build/dist/telegraf-1.23.0~b51bc936_linux_amd64.tar.gz /tmp/telegraf.tar.gz
RUN tar xzv -C /usr/bin -f /tmp/telegraf.tar.gz ./telegraf-1.23.0/usr/bin/telegraf --strip-components=4

with that, the automated test is working again