在 set_by_lua OpenResty 中添加换行符答案

【问题标题】：Append newline in set_by_lua OpenResty在 set_by_lua OpenResty 中添加换行符
【发布时间】：2020-10-19 14:00:15
【问题描述】：

使用https://openresty.org/en/ 我有以下nginx.conf 文件

我正在尝试在 set_by_lua 部分的每个请求标头之间添加一个换行符 \n，然后将其输出到 access.log 文件。

http {
    # Trying to see the request headers nicely in the access.log
    # can't seem to get a nice line feed in from lua
    log_format  main  '(ra:)$remote_addr - (ru:)$remote_user (time_local:)[$time_local] (request:)"$request" (status:)$status (bodybytessent:)$body_bytes_sent (http_referer)"$http_referer" (useragent:)"$http_user_agent" (xforward:)"$http_x_forwarded_for" \n(requestheaders:)$request_headers';

    access_log  logs/access.log  main;

    server {
        listen       80;
        server_name  localhost;

        location / {

            set_by_lua $request_headers '
              local h = ngx.req.get_headers()
              local request_headers_all = ""
              for k, v in pairs(h) do
                # Here is the problem - the \n does not work
                # just want to append a line feed to this string
                request_headers_all = request_headers_all .. ""..k..": "..v..";" .. "\n"
              end
              return request_headers_all
            ';

            root   html;
            index  index.html index.htm;
        }

...continued

错误是：

2020/06/29 11:36:04 [错误] 8204#8204: *25 未能加载内联 Lua 代码：set_by_lua:6: '"' 附近未完成的字符串

这行是问题所在：

request_headers_all = request_headers_all .. ""..k..": "..v..";" .. "\n"

所以这是某种逃避问题。 Lua ignore Escape Sequence 我迷路了。

基础操作系统是 Ubuntu 18.04。我正在尝试将这样的内容放入 access.log 文件中：

而不是这个：

(ra:)37.152.225.237 - (ru:)- (time_local:)[29/Jun/2020:11:47:46 +0000] (request:)"GET / HTTP/1.1" (status:)200 (bodybytessent:)422 (http_referer)"-" (useragent:)"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:77.0) Gecko/20100101 Firefox/77.0" (xforward:)"-"
(requestheaders:)host: openrestytest836.westeurope.cloudapp.azure.com;accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8;upgrade-insecure-requests: 1;cache-control: no-cache;accept-language: en-GB,en;q=0.5;user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:77.0) Gecko/20100101 Firefox/77.0;pragma: no-cache;connection: keep-alive;accept-encoding: gzip, deflate;

有很多方法可以做到这一点，但我很好奇如何将换行符放入 Lua 生成的字符串中。

【问题讨论】：

你试过使用set_by_lua_block吗？ set_by_lua 已弃用。 *_block 指令没有转义问题：github.com/openresty/…
顺便说一句，table.insert + table.concat 比重复连接更有效。

标签： nginx lua openresty

【解决方案1】：

感谢上面 cmets 中的 @un.def 修复了现在的 Lua 问题：

set_by_lua_block $request_headers {
     local h = ngx.req.get_headers()
     local request_headers_all = ""
     for k, v in pairs(h) do
         request_headers_all = request_headers_all .. ""..k..": "..v.."\n"
     end
     return request_headers_all
}

我还没有尝试过建议的餐桌策略。

来自http://nginx.org/en/docs/http/ngx_http_log_module.html

我还必须在 log_format 中设置esacpe=none：

log_format  main escape=none '(remote_addr:)$remote_addr - (remote_user:)$remote_user (time_local:)[$time_local] (request:)"$request" (status:)$status (bodybytessent:)$body_bytes_sent (http_referer)"$http_referer" (useragent:)"$http_user_agent" (xforward:)"$http_x_forwarded_for" \n(requestheaders:)\n$request_headers';

给出所需的输出：

【讨论】：