Dotted cookie name as proxy_cache_key problem

[SergeyZh]

I've tried this already, but there's config error:
: the closing bracket in "cookie_jetbrains" variable is missing in /usr/local/nginx/conf/nginx.conf:178

Also I've tried:
proxy_cache_key "$host$request_uri $cookie_jetbrains\.charisma\.main\.security\.PRINCIPAL";
and with \\ and \\\ before dot, without success. :-(
There no error, but no success too.

Thanks,
Sergey

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,62326,62693#msg-62693