openresty
always_forward_body=true not working
My nginx has the following configuration (it forwards and mirrors the parent request to the /pgsql, /mongo locations, and receives the response result of /pgsql)
http {
......
log_subrequest on;
proxy_buffering off;
proxy_request_buffering off;
......
}
location /test
{
error_log /data/logs/error.log debug;
lua_need_request_body on;
content_by_lua_block {
local reqBody = ngx.req.get_body_data()
local reqUri = ngx.var.uri or ""
local resPg, resMongo = ngx.location.capture_multi( {
{"/pgsql".. reqUri, { method = ngx.HTTP_POST, body = reqBody , args = ngx.var.args, always_forward_body=true }},
{"/mongo".. reqUri , { method = ngx.HTTP_POST, body = reqBody , args = ngx.var.args, always_forward_body=true }}
})
ngx.status = resPg.status
for k, v in pairs(resPg.header) do
ngx.header[k] = v
end
ngx.print(resPg.body)
}
}
location /pgsql
{
if ($request_method = 'OPTIONS') {
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' '*';
add_header 'Access-Control-Expose-Headers' '*';
add_header 'Content-Type' 'text/plain charset=UTF-8';
add_header 'Content-Length' 0;
return 204;
}
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' '*';
add_header 'Access-Control-Expose-Headers' '*';
rewrite ^/pgsql/test$ $original_path break;
proxy_pass http://xxx:xxx/test;
proxy_http_version 1.1;
proxy_set_header Connection "";
}
location /mongo
{
if ($request_method = 'OPTIONS') {
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' '*';
add_header 'Access-Control-Expose-Headers' '*';
add_header 'Content-Type' 'text/plain charset=UTF-8';
add_header 'Content-Length' 0;
return 204;
}
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' '*';
add_header 'Access-Control-Expose-Headers' '*';
rewrite ^/mongo/test$ $original_path break;
proxy_pass http://xxx:xxx/test;
proxy_http_version 1.1;
proxy_set_header Connection "";
}
......
I hope nginx can forward requests in a streaming manner (forward when receiving a request, forward when receiving a response), so I configured proxy_buffering off, proxy_request_buffering off, always_forward_body=true. But after capturing the packet, I found that
- The subrequests of /pgsql and /mongo are forwarded only after receiving the body of the parent request;
- The response result is also forwarded only after receiving the response of /pgsql;
I saw the documentation description：always_forward_body when set to true，...... The request body read by either ngx.req.read_body() or lua_need_request_body on will be directly forwarded to the subrequest without copying the whole request body data when creating the subrequest (no matter the request body data is buffered in memory buffers or temporary files).
Can someone take a look at and give me some guidance?
Thanks.
nginx version
/usr/local/openresty/nginx/sbin/nginx -V
nginx version: openresty/1.19.9.1
built by gcc 9.3.1 20200408 (Red Hat 9.3.1-2) (GCC)
built with OpenSSL 1.1.1k 25 Mar 2021 (running with OpenSSL 1.1.1w 11 Sep 2023)
TLS SNI support enabled
configure arguments: --prefix=/usr/local/openresty/nginx --with-cc-opt='-O2 -DNGX_LUA_ABORT_AT_PANIC -I/usr/local/openresty/zlib/include -I/usr/local/openresty/pcre/include -I/usr/local/openresty/openssl111/include' --add-module=../ngx_devel_kit-0.3.1 --add-module=../echo-nginx-module-0.62 --add-module=../xss-nginx-module-0.06 --add-module=../ngx_coolkit-0.2 --add-module=../set-misc-nginx-module-0.32 --add-module=../form-input-nginx-module-0.12 --add-module=../encrypted-session-nginx-module-0.08 --add-module=../srcache-nginx-module-0.32 --add-module=../ngx_lua-0.10.20 --add-module=../ngx_lua_upstream-0.07 --add-module=../headers-more-nginx-module-0.33 --add-module=../array-var-nginx-module-0.05 --add-module=../memc-nginx-module-0.19 --add-module=../redis2-nginx-module-0.15 --add-module=../redis-nginx-module-0.3.7 --add-module=../ngx_stream_lua-0.0.10 --with-ld-opt='-Wl,-rpath,/usr/local/openresty/luajit/lib -L/usr/local/openresty/zlib/lib -L/usr/local/openresty/pcre/lib -L/usr/local/openresty/openssl111/lib -Wl,-rpath,/usr/local/openresty/zlib/lib:/usr/local/openresty/pcre/lib:/usr/local/openresty/openssl111/lib' --with-cc='ccache gcc -fdiagnostics-color=always' --with-pcre-jit --with-stream --with-stream_ssl_module --with-stream_ssl_preread_module --with-http_v2_module --without-mail_pop3_module --without-mail_imap_module --without-mail_smtp_module --with-http_stub_status_module --with-http_realip_module --with-http_addition_module --with-http_auth_request_module --with-http_secure_link_module --with-http_random_index_module --with-http_gzip_static_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-threads --with-compat --with-stream --with-http_ssl_module
The subrequests of /pgsql and /mongo are forwarded only after receiving the body of the parent request;
lua_need_request_body is on,that means the request body data need to be read before running rewrite/access/content_by_lua*.
The response result is also forwarded only after receiving the response of /pgsql;
ngx.location.capture* issues a synchronous but still non-blocking Nginx subrequest using uri. So when ngx.location.capture* is called, it will return until it get the entire response body.
If you really need to request 2 or more upstreams in a streaming manner, I think ngx.location.capture_multi cannot do this job, you need to write some lua code to do this.
The above is my personal understanding, if there are any mistakes, please help to correct them.
