bug: When I turn on kafka-logger and body-transformer at the same time, the response body conversion of body-transformer plugin will fail.

[FirstCatchYourHare]

Current Behavior

When I turn on kafka-logger and body-transformer at the same time, the response body conversion of body-transformer plugin will fail. After turning off kafka-logger, body-transformer plug-in will fail

Expected Behavior

I hope that when I turn on kafka-logger and body-transformer at the same time, both will work properly at the same time

Error Logs

When I turn on kafka-logger and body-transformer at the same time,By tracking the source code log,I found that when the body-transformer plugin code went to body_filter, it got an empty response table, so the conversion failed, but the request was still successful, but no response body was returned

function M.body_filter(, ctx)
local conf = ctx.body_transformer_conf
if conf.response then
local body = core.response.hold_body_chunk(ctx)
core.log.error(cjson.encode(body))
if ngx.arg[2] == false and not body then
return
end

    local out = transform(conf, body, "response", ctx)
    if not out then
        core.log.error("failed to transform response body: ", body)
        return
    end

    ngx.arg[1] = out
end

end

Steps to Reproduce

1.Enable plug-ins kafka-logger and body-transformer at the same time
2.The upstream service is a webservice
3.By configuring body-transformer, you mainly convert the xml response body to the json response body

Environment

• APISIX version (run apisix version):apache/apisix-3.2.0-debian
• Operating system (run uname -a):Linux new 3.10.0-1127.el7.x86_64 change: added doc of how to load plugin. #1 SMP Tue Mar 31 23:36:51 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
• OpenResty / Nginx version (run openresty -V or nginx -V):nginx version: openresty/1.21.4.1
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info):3.5.0
• APISIX Dashboard version, if relevant:apache/apisix-dashboard 3.0.0-alpine
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[FirstCatchYourHare]

Suddenly think of it, it may be the reason why the http response body can not be read twice

[FirstCatchYourHare]

this bug is resolved at apisix3.2.2

[Baoyuantop]

If there is still a problem, please open it again.