Logs not being captured up by inputs.exec #18508
Description
Relevant telegraf.conf
[[inputs.exec]]
commands = ["/etc/telegraf/testscript.py"]
data_format = "influx"Logs from Telegraf
026-03-10T21:14:08Z I! Loading config: telegraf.conf
2026-03-10T21:14:08Z I! Starting Telegraf 1.38.0 brought to you by InfluxData the makers of InfluxDB
2026-03-10T21:14:08Z I! Available plugins: 244 inputs, 9 aggregators, 35 processors, 26 parsers, 68 outputs, 8 secret-stores
2026-03-10T21:14:08Z I! Loaded inputs: exec
2026-03-10T21:14:08Z I! Loaded aggregators:
2026-03-10T21:14:08Z I! Loaded processors:
2026-03-10T21:14:08Z I! Loaded secretstores:
2026-03-10T21:14:08Z W! Outputs are not used in testing mode!
2026-03-10T21:14:08Z I! Tags enabled: host=ubuntu
2026-03-10T21:14:08Z W! [agent] The default value of 'skip_processors_after_aggregators' will change to 'true' with Telegraf v1.40.0! If you need the current default behavior, please explicitly set the option to 'false'!
2026-03-10T21:14:08Z D! [agent] Initializing plugins
2026-03-10T21:14:08Z D! [agent] Starting service inputs
2026-03-10T21:14:08Z D! [agent] Stopping service inputs
2026-03-10T21:14:08Z D! [agent] Input channel closed
> TSDB_output,host=ubuntu,test=test value=1 1773177249000000000
2026-03-10T21:14:08Z D! [agent] Stopped Successfully
System info
Ubuntu 24.04.4
Docker
No response
Steps to reproduce
- Create Telegraf config with config above.
- Create Python script to print test output along with a warning message
- Execute config
...
Expected behavior
Telegraf would have emitted the warning error that was printed to stderr also. i.e.
2026-03-10T21:14:08Z D! [agent] Input channel closed
TSDB_output,host=ubuntu,test=test value=1 1773177249000000000
2026-03-10T21:14:08Z E! [telegraf] Error running agent: Error alarm from this script
2026-03-10T21:14:08Z D! [agent] Stopped Successfully
Actual behavior
Telegraf is ignoring / excluding error sent to stderr
Additional info
Python Script to recreate:
#!/usr/bin/python3
import sys
print("TSDB_output,test=test value=1")
print("Error alarm from this script", file=sys.stderr)