Change default user agent

[nikonhub]

Hello.

According to prometheus scrape behavior here Change default go http client user-agent
from "Go-http-client/1.1" to "BlackBox Exporter/{{ version }}"

Issue : #555
Maintainers : @brian-brazil

[nikonhub]

By the way I checked the case of null value.
I think it goes beyond the simple test of key exists because it's not in module.HTTP.

I tried to remove the omitempty but no changes
I found that a nil value can not be assigned to a string.

Headers                      map[string]string       `yaml:"headers,omitempty"`

[brian-brazil]

omitempty affects marshalling, not unmarshalling. Null values are fun, we've had many bugs due to them.

[edevil]

This seems like a useful change. Is there some work to do besides fixing the conflicts?

[brian-brazil]

Hmm, looks like that's the case. Better handling of not sending the header at all would also be good.

[nikonhub]

Yo.

Would you like me to do anything ? Honestly I'm not sure what to do about this PR. I followed this issue #555, and it's been one year with no update on this PR nor the issue. Is it still useful ?

Personnaly I just set the User-Agent to BlackBox in config yml to get the same behaviour.

Edit : Sentence meaning

[brian-brazil]

It is still useful. It's technically breaking, but it doesn't hurt to help track where requests are coming from.

Resolving the conflicts, and allowing for no header to be set if practical, would be good.

[cofyc]

any progress?

[megamorf]

I'd also like to see this merged.

Use case:
Identify monitoring traffic and exclude it from application logs.

[SuperQ]

Going to close and re-open this to see if the tests still pass.

[SuperQ]

Seems like this is ready to go.