Wavefront output plugin adding empty tag

[farukhali]

Relevant telegraf.conf

[[outputs.wavefront]]
  host = "somehost"
  port = 12878
  prefix = "\u2206telegraf."
  namepass = ["somenamepass*"]
  fielddrop = ["ln*" , "tdigest"]
  source_override = ["api"]

System info

1.21.0

Docker

No response

Steps to reproduce

1. Use wavefront output.
2. add source override tag.
3. Do not provide host tag in metric.
4. Plugin will add empty telegraf.host tag to the metric sent to wavefront proxy.
5. Wavefront will return error for empty tag.
   ...

Expected behavior

Wavefront output plugin should not expect host tag in source metric. There should not be any empty tag output from this plugin.

Actual behavior

If host tag is not provided in metrics, wavefront output plugin add empty telegraf.host tag which cause failure on wavefront proxy end.

Additional info

The code here

telegraf/plugins/outputs/wavefront/wavefront.go

Line 193 in 4a15e0a

mTags["telegraf_host"] = mTags["host"]

assume there will always be host tag. I can share a PR to fix this issue.

[powersj]

Wavefront output plugin should not expect host tag in source metric. There should not be any empty tag output from this plugin.

Looking at the wavefront data format it does appear that source now, previously host was a required field.

I can share a PR to fix this issue.

Please do, but keep in mind we don't want to go breaking existing users by dropping tags suddenly.

[farukhali]

Proposal is not to drop tag. It's just if the tag is missing don't add empty tag. Here is the PR #11078