Configure Nginx for file upload using connect-busboy - node.js

Question

I have an API in NodeJS where I can upload a file, and I receive it on the server side using the connect-busboy package.
So, for example, here is a part of the code that handles the request:
var app = require('express')();
var busboy = require('connect-busboy');
app.use(busboy({
highWaterMark: 2 * 1024 * 1024,
limits: {
fileSize: 1024 * 1024 * 1024 // 1 GB
},
immediate: true
}));
var busboyHandler = function (req, res) {
if (req.busboy) {
req.busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
console.log('received file ', req.path, fieldname, file, filename, encoding, mimetype);
});
req.busboy.on('field', function(key, value, keyTruncated, valueTruncated) {
console.log('field..', key, value, keyTruncated, valueTruncated);
});
req.busboy.on('finish', function() {
console.log('busboy finished');
});
}
};
app.post('api/documents/files', busboyHandler);
This works well when I start the API with npm start and upload the file to this API directly, however, when I configure an Nginx Docker, it works for really small files, but for most files, they don't get uploaded successfully.
Here is an excerpt from my nginx.conf file:
user nobody nogroup;
worker_processes auto; # auto-detect number of logical CPU cores
events {
worker_connections 512; # set the max number of simultaneous connections (per worker process)
}
http {
include mime.types;
client_max_body_size 100M;
client_body_buffer_size 256k;
upstream api_doc {
server 192.168.2.16:4956;
}
server {
listen *:4000; # Listen for incoming connections from any interface on port 80
server_name localhost; # Don't worry if "Host" HTTP Header is empty or not set
root /usr/share/nginx/html; # serve static files from here
client_max_body_size 100M;
client_body_buffer_size 256k;
location /api/documents {
proxy_pass http://api_doc;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
}
}
}
I see the received file log, but when it's under Nginx, there is never a busboy finished log, unlike when calling the API directly without Nginx.
I tried changing these Nginx configs but it did not work: client_max_body_size, client_body_buffer_size. It looks to me like the API receives only a chunk of the file for larger files, instead of the whole file, or all chunks, as it should.
Any help would be appreciated.
Thanks,
Simon

Answer 1

It turned out that the problem was elsewhere, I was starting to read the incoming stream before the file was fully uploaded, so it led to breaking the incoming stream for some reasons.