apache/apisix

help request: plugins question that cant use grpc-transcode with ext-plugin-post-resp

Open

#10787 opened on Jan 9, 2024

View on GitHub
 (10 comments) (0 reactions) (0 assignees)Lua (16,597 stars) (2,860 forks)batch import
docgood first issue

Description

Description

I need use two plugins: grpc-transcode and ext-plugin-post-resp. There is no problem with these two plugins when used alone, but some problems occur when they are used together. When i use grpc-transcode and ext-plugin-post-resp together, the api response is :

{
    "code": 5,
    "message": "Not Found",
    "details": []
}

and some errors in apisix:

access_by_lua(nginx.conf:292):2: in main chunk xxx
/apisix/apisix/init.lua:730: in function 'http_access_phase'
[C]: in function 'handle_upstream'
coroutine 0:
stack traceback:
[error] 57#57: *872933 lua entry thread aborted: runtime error: /apisix/apisix/init.lua:730: attempt to call ngx.exec after sending out response headers

both plugins do their job correctly, upstream grpc service receive the request and returns right and ext-plugin-post-resp also print out logs after grpc service returns. I don't know how I should troubleshoot the problem next.

Environment

  • APISIX version : 3.6.0
  • Operating system : Ubuntu 16.04.1 LTS
  • OpenResty / Nginx version : nginx/1.20.1
  • etcd version, if relevant : 3.5.0

Contributor guide

Tech stack
None
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
needs maintainer response
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
Basic understanding of Apache APISIXKnowledge of Lua and OpenResty phasesFamiliarity with gRPC transcode and ext plugin post resp plugins
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Examine the interaction between grpc transcode and ext plugin post resp plugins, focusing on the 'ngx.exec after sending out response headers' error in init.lua:730. Investigate the execution order of plugins and whether they attempt to modify the response after headers are sent. Look at the plugin source code in the apisix/plugins/ directory for any conflicts. Consider if a fix requires adjusting plugin priority or avoiding ngx.exec in the access phase.