http_response plugin isn't passing headers

[cheald]

I have a Telegraf input configured as so:

[[inputs.http_response]]
  address = "http://127.0.0.1/features/"
  response_timeout = 10
  method = "GET"
  [inputs.http_response.headers]
    Host = "mydomain.com"

But headers aren't being passed. When I turn on debug logging in nginx, I see that the Host headers is 127.0.0.1, not mydomain.com as expected.

2016/05/13 23:30:20 [debug] 4877#0: *6791491 http request line: "GET /features/ HTTP/1.1"
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http uri: "/features/"
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http args: ""
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http exten: ""
2016/05/13 23:30:20 [debug] 4877#0: *6791491 posix_memalign: 00000000020B6790:4096 @16
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http process request header line
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http header: "Host: 127.0.0.1"
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http header: "User-Agent: Go-http-client/1.1"
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http header: "Accept-Encoding: gzip"
2016/05/13 23:30:20 [debug] 4877#0: *6791491 http header done

Have I misconfigured the input, or is there an actual bug here?

[sparrc]

This is probably because the plugin treats the host tag specially as the Host header. I will make it so it can be overridden by user specified headers.

[sparrc]

looks like this is actually a golang issue that they can't safely change for backwards-compatability reasons: golang/go#7682. We'll need to modify request.Host directly.

[cheald]

Fantastic, thanks!