ngx.ctx varialble not always passed to log phase

yahelba · 2019-02-28T22:15:11+00:00

122347#0: *95839 shutdown() failed (107: Transport endpoint is not connected), client: 127.0.0.1, server: , request: "POST /direct/final_url HTTP/1.0&qu...

ngx.ctx varialble not always passed to log phase

yahelba

not sure if this is the desired behavior.

I'm trying to pass a variable (nested table) using ngx.ctx from 'access' phase to 'log' phase.

in some cases - when the code run ngx.exit(200) and the status is 412. the value does not appear in the log phase

the following is a minimal configuration:

    server {
      listen 1026;
      access_by_lua_block {
        ngx.ctx.test = 1
        ngx.exit(200);
      }
      log_by_lua_block { ngx.log(ngx.ERR, " ngx.ctx: " , ngx.ctx.test) }
   }

to generate 412, i tried:

curl -v -H "IF-UNMODIFIED-SINCE: Sat, 29 Dec 2018 13:02:08 GMT" localhost:1026

expected log:

log_by_lua(nginx.conf:72):1: log ngx.ctx: 1

actual log:

log_by_lua(nginx.conf:72):1: log ngx.ctx: nil

zchao1995

Hello!

The If-Unmodified-Since and If-Match header will lead the Nginx "filter finalize",

and this process will clear all modules' context, includes ngx_lua. Moreover, the ngx.ctx

is really a table which anchored in ngx_lua's context. So when the context was cleared,

the ngx.ctx would be collected by LuaJIT GC.

You can bypass this limitation by using my lua-resty-ctxdump:

https://github.com/tokers/lua-resty-ctxdump