NodeJS + Nginx: busboy behind an nginx reverse proxy

Question

If I spin up a nodejs server and use busboy then I am able to upload large files (10+ gbs) but when i use the same nodejs code and use nginx as a reverse proxy then nginx throws "413 request entity too large"

Has anyone encountered such issue? How do we solve this? I know i can set a "client_max_body_size" variable but this would mean there will still be a hard limit of the file.

My nginx config looks like the following:

server {
  listen 80;
  server_name *.example.local;

  location /api {
    proxy_pass   http://host.docker.internal:5000;
    proxy_pass_header Accept;
    proxy_pass_header Server;
    keepalive_requests 1000;
    proxy_redirect off;
    proxy_buffering off;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Ssl on;
    proxy_set_header    X-Real-IP       $remote_addr;
    proxy_set_header Host $host;
    proxy_http_version 1.1;
    proxy_set_header   Upgrade $http_upgrade;
    proxy_set_header   Connection "upgrade";
    proxy_connect_timeout       600;
    proxy_send_timeout          600;
    proxy_read_timeout          600;
    send_timeout                600;
    client_max_body_size        100M;
  }

}

Answer 1

client_max_body_size size;

Sets the maximum allowed size of the client request body. If the size in a request exceeds the configured value, the 413 (Request Entity Too Large) error is returned to the client. Please be aware that browsers cannot correctly display this error. Setting size to 0 disables checking of client request body size.

Source

Answer 2

In your nginx configuration you have client_max_body_size=100M. You need to adjust it according to your needs like 15G etc. This property of configuration defines the max size of body payload a client can send to Nginx. If payload size is greater than this, a 413 http status is sent to client. Setting it to 0 (as suggested by Taxel) will disable the payload size check but this will expose the server to outside attack where a malicious user keeps your server busy by sending random big files which can deteriorate server performance.

Answer 3

Answering my own question:

In order to disable request/proxy buffering in my nginx reverse proxy, I had to add the following directives in the nginx config file

proxy_buffering off; 
proxy_request_buffering off; 

So, now my nginx config file looks like the following:

server {
  listen 80;
  server_name *.example.local;

  location /api {
    proxy_pass   http://host.docker.internal:5000;
    proxy_pass_header Accept;
    proxy_pass_header Server;
    keepalive_requests 1000;
    proxy_redirect off;
    proxy_buffering off;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Ssl on;
    proxy_set_header    X-Real-IP       $remote_addr;
    proxy_set_header Host $host;
    proxy_http_version 1.1;
    proxy_set_header   Upgrade $http_upgrade;
    proxy_set_header   Connection "upgrade";
    proxy_connect_timeout       600;
    proxy_send_timeout          600;
    proxy_read_timeout          600;
    send_timeout                600;
    client_max_body_size        0;
    proxy_buffering             off; # <-----
    proxy_request_buffering     off; # <-----
  }

}