module-nginx/templates/conf.d/upstream_header.erb

upstream <%= @name %> {
<% if @upstream_cfg_prepend -%><% @upstream_cfg_prepend.sort_by{|k,v| k}.each do |key,value| %>
<% if value.is_a?(Hash) -%><% value.each do |subkey,subvalue| -%>
<% Array(subvalue).each do |asubvalue| -%>
  <%= key %> <%= subkey %> <%= asubvalue %>;
<% end -%>
<% end -%><% else -%>
<% Array(value).each do |asubvalue| -%>
  <%= key %> <%= asubvalue %>;
<% end -%>
<% end -%>
<% end -%><% end -%>