NodeJS + Nginx: busboy behind an nginx reverse proxy - node.js

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; # <-----
}
}