Socket.io with Nodejs not working with nginx reverse proxy - node.js

Question

I have a Nodejs server app with Express and Socket.io (Ubuntu 18.04). It always worked fine until nGinx (1.14) reverse proxy entered the scene. The nginx server is running on a different machine of Node.js apps, each app on it's own vm, inside the same network.
Server and Client on version 2.1.1.
The nginx server is responsible for multiple app redirects.
I tried several configuration combinations but nothing works.
Here what I've tried (examples for "company1"):
default.conf in /etc/nginx/conf.d
location /company1-srv/ {
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "Upgrade";
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-NginX-Proxy true;
proxy_redirect off;
proxy_pass http://172.16.0.25:51001/;
}
Then in the client code I connect using "path" options because socket.io misplace it's library path.
// companySrv and URL is actually returned by another service (following code is for illustrative purposes):
let companyUrl = 'https://api.myserver.com/company1-srv';
let companySrv = '/company1-srv';
socket(companyUrl, {
path: companySrv + '/socket.io/'
});
I also tried to remove the path option and configured a specific /location for the socket.io stuff (for testing purposes):
location /socket.io/ {
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;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-NginX-Proxy true;
proxy_redirect off;
proxy_pass http://172.16.0.25:51001/socket.io/;
}
Nothing worked.
It connects, but does'n emits anything. And after a short while (a minute or so), it becomes unavailable, raising the "disconnect" (reason: transport close) client event.
Server:
const io = require('socket.io')(https || http, {
transports: ['polling', 'websocket'],
allowUpgrades: true,
pingInterval: 60000*60*24,
pingTimeout: 60000*60*24
});
I also tried to edit the nginx.conf and write the "upstream socket_nodes { ..." and use the proxy_pass http://socket_nodes. It didn't make sense as I need a exact redirect depending on the company, but for the sake of tests I did, but it doesn't work as well.
What I need to do?
Thanks

Answer 1

We as well use socket.io with reverse-proxy from ngnix. I can share a little bit of our setup, maybe it helps to rule things out.
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;
events {
worker_connections 768;
}
stream {
log_format basic '$time_iso8601 $remote_addr '
'$protocol $status $bytes_sent $bytes_received '
'$session_time $upstream_addr '
'"$upstream_bytes_sent" "$upstream_bytes_received" "$upstream_connect_time"';
access_log /var/log/nginx/stream.log basic;
}
http {
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
gzip on;
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
##
# Server Blocks
##
# DOMAINEXAMPLE A
server {
server_name exampleA.domain.com;
location / {
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://192.168.21.105:5050;
}
}
# DOMAINEXAMPLE B
server {
server_name exampleB.domain.com;
location /api {
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://192.168.21.106:5050;
}
}
}
The most interesting part here are probably the server blocks
# DOMAINEXAMPLE A
server {
server_name exampleA.domain.com;
location / {
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://192.168.21.105:5050;
}
}
# DOMAINEXAMPLE B
server {
server_name exampleB.domain.com;
location /api {
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://192.168.21.106:5050;
}
}
Domain Example A
For location / at http://192.168.21.105:5050 we have a NodeJS process running, including the setup for socket.io
const express = require('express');
const http = require('http');
const app = express();
const server = http.createServer(app);
const io = require('socket.io')(server);
Domain Example B
For location /api at http://192.168.21.106:5050 we have another NodeJS process running, including a slightly different setup for socket.io
const express = require('express');
const http = require('http');
const app = express();
const server = http.createServer(app);
const io = require('socket.io')(server, {path: '/api/socket.io'});
In both cases socket.io works perfectly fine for us
Connecting from Client (Example B)
What we actually do on the server side here is creating a namespace for socket.io, like
const io= require('socket.io')(server, {path: '/api/socket.io'});
const nsp = io.of('/api/frontend');
and then on the client side , connect to it like
import io from 'socket.io-client'
const socket = io('https://exampleB.domain.com/api/frontend', {path: "/api/socket.io"});