* tls_config: Allow specifying SNI hostnames
Add a new configration field `tls_server_name` that allows specifying
the server name that'll be sent in the ClientHello when telegraf makes
a request to TLS servers. This allows checking against load balancers
responding to specific hostnames that otherwise wouldn't resolve to
their addresses.
Add the setting to the documentation of common TLS options, as well as
to the http_response plugin.
Fixes#7598.
* Adjust the x509_cert to allow usage of tls_server_name
This plugin has been using ServerName previously, and will have to
deal with the new setting, too: Extract the server-name choosing into
a method & add a test to ensure we choose the right value (and error
under the right circumstances). Also document that the two settings
are mutually exclusive.
* Improve documentation on what we try to accomplish in the nil return
Also get rid of the TODO, as I am fairly certain this behavior is the
correct one.
* Remove unused struct field in tests
bustedware
Josef Johansson
Eng Zer Jun
Andreas Fuchs
Daniel Nelson