inputs.prometheus - http_headers - host header ignored

[anthosz]

Relevant telegraf.conf

[[inputs.prometheus]]
  urls = ["http://127.0.0.1/metrics"]
  http_headers = {"host" = "example.org"}

Logs from Telegraf

NC

System info

telegraf 1.29, k8s 1.28

Docker

No response

Steps to reproduce

1. telegraf --test

Expected behavior

The Host header is forwarded

Actual behavior

The Host header is not forwarded

Additional info

The goal is request the pod itself via sidecar based on a specific virtual host.

Currently, if I try curl -H 'Host: example.org' http://127.0.0.1/metrics, I can extract datas.

But with telegraf, the Host is not forwarded.
Host received from access log: localhost

[powersj]

Hi,

The Host header is not forwarded

How are you determining that this is not occurring? Do you have a network trace demonstrating this?

The headers are set here right before any request.

[anthosz]

Hi,

The Host header is not forwarded

How are you determining that this is not occurring? Do you have a network trace demonstrating this?

The headers are set here right before any request.

Hello,

unfortunaely not, I just tried a telegraf --test vs a curl with -H 'Host:' -> with the first one, Apache receive "localhost", second one is example.org (curl)

I tried with 127.0.0.1 & the IP of pod.

[powersj]

So after looking at this more, I remembered that the host key is a special header. I've seen this before, and sure enough: https://github.com/influxdata/telegraf/pull/14481/files

I've put up #15195 with a fix

[anthosz]

Thank you very much @powersj ! So fast!

In addition, out of scope but do you know if telegraf-operator is always supported? (related to the issue: influxdata/telegraf-operator#137)

[powersj]

In addition, out of scope but do you know if telegraf-operator is always supported? (related to the issue: influxdata/telegraf-operator#137)

The individual who built and maintained that left the company last year. I don't think anyone has decided to pick it up and it is why the support statement was updated to say no official support.

If there was a specific PR that needed a review I think we might be able to convince someone to look at it who knows the operator/k8s framework better than I do 😄

[anthosz]

In addition, out of scope but do you know if telegraf-operator is always supported? (related to the issue: influxdata/telegraf-operator#137)

The individual who built and maintained that left the company last year. I don't think anyone has decided to pick it up and it is why the support statement was updated to say no official support.

If there was a specific PR that needed a review I think we might be able to convince someone to look at it who knows the operator/k8s framework better than I do 😄

Thank you for the details!