Websocket on Docker with nginx - docker

Question

I am trying to build a service with two parts: a backend and a frontend. Both are on a different docker container and are communicating through the docker-compose configuration and a nginx container.
For https access, everything's good, but when I am trying to work with websocket, I have an upgrade error, even if the Nginx configuration got this information
Error message : websocket: the client is not using the websocket protocol: 'upgrade' token not found in 'Connection' header
I am using a fasthttp and fasthttp/websocket for my Golang backend. The code is working on localhost (no nginx configuration), but the combinaison of Docker + nginx seems to break something.
The front-end works with react and is a simple let socket = new WebSocket(wss.mydomain.com/ws/uploadPicture/);
EDIT :
when using ctx.Request.Header.ConnectionUpgrade() just before upgrader.Upgrade, the result is true, but ctx.Response.Header.ConnectionUpgrade() is false
Thank you !
Golang Backend
var upgrader = websocket.FastHTTPUpgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(ctx *fasthttp.RequestCtx) bool {
return true
},
}
func InitRouter() func(*fasthttp.RequestCtx) {
router := fasthttprouter.New()
router.GET("/ws/uploadPicture/", doWS)
return router.Handler
}
func doWS(ctx *fasthttp.RequestCtx) {
err := upgrader.Upgrade(ctx, func(conn *websocket.Conn) {
//SHOULD DO STUFF
})
if (err != nil) {
logs.Error(err.Error()) //HIT THIS ERROR
return
}
}
...
fasthttp.ListenAndServe(`:8000`, InitRouter())
Nginx.conf
#############################################################################
## NGINX CONFIGURATION FOR THE WEBAPP
#############################################################################
upstream webapp {
server webapp:3000;
keepalive 4;
}
server {
listen [::]:443 ssl;
listen 443 ssl;
server_name mydomain.com;
ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
location / {
proxy_pass http://webapp;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $host;
proxy_redirect off;
}
}
#############################################################################
## NGINX CONFIGURATION FOR THE PROXY
#############################################################################
upstream proxy {
server proxy:8000;
keepalive 4;
}
server {
listen [::]:443 ssl;
listen 443 ssl;
server_name api.mydomain.com;
ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
location / {
add_header 'Access-Control-Allow-Origin' "$http_origin";
add_header 'Access-Control-Allow-Credentials' true;
proxy_pass http://proxy;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $host;
proxy_redirect off;
}
}
#############################################################################
## NGINX CONFIGURATION FOR THE PROXY
#############################################################################
upstream proxyws {
server proxy:8000;
keepalive 4;
}
server {
listen [::]:443 ssl;
listen 443 ssl;
server_name wss.mydomain.com;
ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
location / {
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_redirect off;
proxy_pass http://proxyws;
}
}
Docker-compose
#############################################################################
## IMAGE FOR THE PROXY
#############################################################################
proxy:
container_name: proxy
build: ./src/Proxy
restart: always
env_file: .env
ports:
- "8000:8000"
#############################################################################
## IMAGE FOR THE WEBAPP
#############################################################################
webapp:
container_name: webapp
build: ./src/Webapp
restart: always
volumes:
- ./src/Webapp:/home/app
- /home/app/.next
- /home/app/node_modules
ports:
- 3000:3000
#############################################################################
## IMAGE THE NGINX & CERTBOT FOR REVERSE PROXY
#############################################################################
nginx:
image: nginx:latest
container_name: nginx
volumes:
- ./data/nginx:/etc/nginx/conf.d
- ./data/certbot/conf:/etc/letsencrypt
- ./data/certbot/www:/var/www/certbot
ports:
- 80:80
- 443:443

Answer 1

I'm the maintainer of websocket package for fasthttp. The issue is fixed on master branch.
Downdload it with:
go get github.com/fasthttp/websocket#master
And try again, please.
If the issue continue, please open an issue in https://github.com/fasthttp/websocket/issues
Soon, I will release a new version.

Answer 2

Turns out it's not an issue with Nginx/Docker, but with the http package in golang that is supposed to upgrade the connection.
I was using fasthttp with fasthttp/websocket wich is supposed to work, but which does not in a docker container.
I tried to switch to httprouter with the official (not fork as for the fasthttp ones) gorilla/websocket and the connection successfully upgrade.
Gonna check where the issue come from !

Answer 3

I believe upgrade should be a string:
proxy_set_header Connection "upgrade";