How to use subrequests

server {
  location / {
    content_by_lua_block {
      local res = ngx.location.capture('/page?test=1')
      ngx.say(res.body)
    }
  }
}

content_by_lua_block - lib:nginx-lua module directive to specify block of Lua code
ngx.location.capture - executes sync Nginx subrequest to the specified URI
/page?test=1 - sample URL with arguments to make subrequest to
local res - this table will have 4 fields: status, header, body and truncated
ngx.say - output given text to client
res.body - response body returned after subrequest execution

Example:

local res = ngx.location.capture('/ip')
ngx.say(res.body)

3.123.32.182