promclient: Misleading error message about enabling Prometheus admin API

[beorn7]

Thanos, Prometheus and Golang version used

Thanos at commit f6992f7

What happened

thanos/pkg/promclient/promclient.go

Line 79 in f6992f7

return nil, errors.Errorf("is 'web.enable-admin-api' flag enabled? got non-200 response code: %v, response: %v", resp.StatusCode, string(b))

suggests to set --web.enable-admin-api for Prometheus if a non-200 response is encountered. However, the endpoint used there is not part of the Prometheus admin API.

thanos/pkg/promclient/promclient.go

Line 245 in f6992f7

return "", errors.Errorf("got non-200 response code: %v, response: %v", resp.StatusCode, string(b))

, however, does not contain that suggestion, despite dealing with an admin API endpoint (snapshot).

What you expected to happen

It should be the other way round.

[beorn7]

In case you agree, I have prepared #1355 .