nginx header 지시자 구분


https://stackoverflow.com/questions/12431496/nginx-read-custom-heade
r-from-upstream-server

client   -> nginx     : the client request headers
nginx    -> upstream  : the upstream request headers
upstream -> nginx     : the upstream response headers
nginx    -> client    : the client response headers

---------------------------------------------------------------------
from      to       type        read (variable)      write (directive)
---------------------------------------------------------------------
client	  nginx    request    $http_{name}          –
ngnix	  upstream request    –                     proxy_set_header
upstream  nginx    response   $upstream_http_{name} –
nginx     client   response   $sent_http_{name}     add_header
---------------------------------------------------------------------