lua entry thread aborted: runtime error: rewrite_by_lua - nginx

Question

The nginx.conf file looks like this:
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
load_module modules/ndk_http_module.so;
load_module modules/ngx_http_lua_module.so;
events {
worker_connections 1024;
}
http {
proxy_ssl_session_reuse off;
proxy_buffering on;
proxy_buffer_size 4k;
proxy_buffers 32 4k;
proxy_max_temp_file_size 0;
proxy_read_timeout 3600;
keepalive_timeout 10m;
proxy_connect_timeout 600s;
fastcgi_send_timeout 600s;
send_timeout 600;
fastcgi_read_timeout 600s;
lua_package_path "./lua/?.lua;;";
# include /etc/nginx/mime.types;
default_type application/octet-stream;
log_format main2 '$remote_addr - $remote_user [$time_local] '
'\n\n"$request" \n status: $status body_bytes_sent: $body_bytes_sent '
'\n\n http_referer: "$http_referer" \n "$http_user_agent" $request_time '
'\n\n req_headers: \n "$req_headers" \n\n req_body: \n "$req_body" \n\n resp_body: \n "$resp_body"';
access_log /var/log/nginx/access.log main2;
sendfile on;
#tcp_nopush on;
# keepalive_timeout 65;
#gzip on;
# include /etc/nginx/conf.d/*.conf;
server {
server_name xxxxxxxxxxxxx.com;
listen 80;
lua_need_request_body on;
set $resp_body "";
set $req_body "";
set $req_headers "";
client_body_buffer_size 16k;
client_max_body_size 16k;
rewrite_by_lua_block {
local req_headers = "Headers: ";
ngx.var.req_body = ngx.req.get_body_data();
local h, err = ngx.req.get_headers()
for k, v in pairs(h) do
req_headers = req_headers .. k .. ": " .. v .. "\n";
end
ngx.var.req_headers = req_headers;
}
body_filter_by_lua '
local resp_body = string.sub(ngx.arg[1], 1, 1000)
ngx.ctx.buffered = (ngx.ctx.buffered or "") .. resp_body
if ngx.arg[2] then
ngx.var.resp_body = ngx.ctx.buffered
end
';
location / {
proxy_pass https://xxxxxxxxxxxxx.com;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# proxy_set_header Host $http_host;
proxy_set_header Cookie $http_cookie;
proxy_ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
proxy_ssl_ciphers GOST2012-GOST8912-GOST8912:HIGH:MEDIUM;
proxy_ssl_certificate /etc/nginx/ssl/ivanovIvanIvanovich.pem;
proxy_ssl_certificate_key /etc/nginx/ssl/prkeyunitIvanov.key;
proxy_ssl_server_name on;
# proxy_redirect off;
# root html;
# index index.html index.htm;
}
}
server {
listen 8080;
lua_need_request_body on;
set $resp_body "";
set $req_body "";
set $req_headers "";
client_body_buffer_size 16k;
client_max_body_size 16k;
rewrite_by_lua_block {
local req_headers = "Headers: ";
ngx.var.req_body = ngx.req.get_body_data();
local h, err = ngx.req.get_headers()
for k, v in pairs(h) do
req_headers = req_headers .. k .. ": " .. v .. "\n";
end
ngx.var.req_headers = req_headers;
}
body_filter_by_lua '
local resp_body = string.sub(ngx.arg[1], 1, 1000)
ngx.ctx.buffered = (ngx.ctx.buffered or "") .. resp_body
if ngx.arg[2] then
ngx.var.resp_body = ngx.ctx.buffered
end
';
location / {
proxy_pass https://xxxxxxxxxxxxx.com;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Cookie $http_cookie;
proxy_ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
proxy_ssl_ciphers GOST2012-GOST8912-GOST8912:HIGH:MEDIUM;
proxy_ssl_certificate /etc/nginx/ssl/PetrovIvanSemenovich.pem;
proxy_ssl_certificate_key /etc/nginx/ssl/prkeyunitSemenovich.key;
proxy_ssl_server_name on;
}
}
server {
listen 8585;
lua_need_request_body on;
set $resp_body "";
set $req_body "";
set $req_headers "";
client_body_buffer_size 16k;
client_max_body_size 16k;
rewrite_by_lua_block {
local req_headers = "Headers: ";
ngx.var.req_body = ngx.req.get_body_data();
local h, err = ngx.req.get_headers()
for k, v in pairs(h) do
req_headers = req_headers .. k .. ": " .. v .. "\n";
end
ngx.var.req_headers = req_headers;
}
body_filter_by_lua '
local resp_body = string.sub(ngx.arg[1], 1, 1000)
ngx.ctx.buffered = (ngx.ctx.buffered or "") .. resp_body
if ngx.arg[2] then
ngx.var.resp_body = ngx.ctx.buffered
end
';
location / {
proxy_pass https://xxxxxxxxxxxxx.com;
proxy_ssl_server_name on;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Cookie $http_cookie;
proxy_ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
proxy_ssl_ciphers GOST2012-GOST8912-GOST8912:HIGH:MEDIUM;
proxy_ssl_certificate /etc/nginx/ssl/Petrovich.pem;
proxy_ssl_certificate_key /etc/nginx/ssl/prkeyunitPetrovich.key;
}
}
}
error.log
2023/01/23 07:50:11 [error] 3294740#3294740: *2312 lua entry thread aborted: runtime error: rewrite_by_lua(nginx.conf:194):6: attempt to concatenate local 'v' (a table value)
stack traceback:
coroutine 0:
rewrite_by_lua(nginx.conf:194): in function <rewrite_by_lua(nginx.conf:194):1>, client: XX.XXX.XXX.89, server: , request: "POST /INC/zkau;jsessionid=cu9a1076567akai7q9hjr4h HTTP/1.1", host: "XX.XXX.XX.XXX:8585", referrer: "http://XX.XXX.XX.XXX/INC/INC/scroller.zul?navigationId=INC_ApplRefund_D07_2"
2023/01/23 07:52:01 [error] 3294740#3294740: *2337 peer closed connection in SSL handshake (104: Connection reset by peer) while SSL handshaking to upstream, client: XX.XXX.XXX.89, server: , request: "POST /INC/zkau;jsessionid=1koc01pjtptx01dg6yskg6mndo HTTP/1.1", upstream: "https://XX.XXX.X.60:443/INC/zkau;jsessionid=1koc01pjtptx01dg6yskg6mndo", host: "XX.XXX.XX.XXX:8585", referrer: "http://XX.XXX.XX.XXX/INC/INC/scroller.zul?navigationId=D04_Client"
2023/01/23 14:28:38 [error] 3294740#3294740: *2724 lua entry thread aborted: runtime error: rewrite_by_lua(nginx.conf:194):6: attempt to concatenate local 'v' (a table value)
stack traceback:
coroutine 0:
rewrite_by_lua(nginx.conf:194): in function <rewrite_by_lua(nginx.conf:194):1>, client: XX.XXX.XXX.89, server: , request: "POST /INC/zkau;jsessionid=1ubqzl52zhbbz1d6zpytdgsd8i HTTP/1.1", host: "XX.XXX.XX.XXX:8585", referrer: "http://XX.XXX.XX.XXX/INC/INC/scroller.zul?navigationId=INC_ApplRefund_D07_2"
2023/01/23 14:44:25 [error] 3294740#3294740: *2796 lua entry thread aborted: runtime error: rewrite_by_lua(nginx.conf:194):6: attempt to concatenate local 'v' (a table value)
stack traceback:
coroutine 0:
rewrite_by_lua(nginx.conf:194): in function <rewrite_by_lua(nginx.conf:194):1>, client: XX.XXX.XXX.89, server: , request: "POST /INC/zkau;jsessionid=mm26zovs3fwo1xnstgy39zlhi HTTP/1.1", host: "XX.XXX.XX.XXX:8585", referrer: "http://XX.XXX.XX.XXX/INC/INC/scroller.zul?navigationId=INC_ApplRefund_D07_2"
The error related to "peer closed connection in SSL handshake" was fixed by adding:
proxy_ssl_session_reuse of;
But it can still be observed in the logs.
Now I am more interested in how to fix the error
[error] 3294740#3294740: *2796 lua entry thread aborted: runtime error: rewrite_by_lua(nginx.conf:194):6: attempt to concatenate local 'v' (a table value)
stack traceback:
In Jmeter, this error looks like this:
<html>
<head><title>500 Internal Server Error</title></head>
<body>
<center><h1>500 Internal Server Error</h1></center>
<hr><center>nginx/1.18.0 (Ubuntu)</center>
</body>
</html>
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<!-- a padding to disable MSIE and Chrome friendly error page -->
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But in Jmeter, it strongly describes what causes it. Therefore, I attached the nginx log
I would be glad if you could help me fix these errors.

Answer 1

attempt to concatenate local 'v' (a table value)
This is pretty obvious. You're attempting to concatenate a table value.
You can only concat table values if that table has a metatable implementing __concat, which obviously is not the case.
Now I am more interested in how to fix the error
Well don't concat the table value.
Refer to the manual of the Lua Ngx API and you'll find that ngx.req.get_headers() returns a table of tables. Not a table of strings or numbers.
Run a loop over each table in the table returned by ngx.req.get_headers() and do your concat thing.