Example Voting App with proxy

Docker Hub
1

Hi,

This fork of the Example Voting App says it’s using a proxy :

But why there’s no proxy at all in the compose yml file ?

There’s a proxy folder, but it’s not used elsewhere.

Is it because they don’t know how to achieve this with the proxy ?

Thanks

2

Isn’t that question more suited for an issue post in the Github project you provided?

3

You are right, I wrote there :

But I still have a general question of how I can setup a proxy in front of this kind of app, using docker-compose, and using docker swarm (docker service create).

4

Are you familiar with setting up reverse proxy rules with nginx? You will basicly need to mount the nginx.conf holding your reverse proxy rules to /etc/nginx/nginx.conf and make sure to use the service names of the target container in the proxy_pass directives. Whetever you do, do NOT use container ips in the proxy_pass directive.

This thead discusses some useful details about nginx as a reverse proxy with docker (it is valid for non swarm deplyoments as well).

5

I can now set up the proxy, thank you!

Bret Fisher says that we need a proxy in front because the websocket must talk to a specific container.

If I use multiple replicas in the frontend and/or backend, how can I tell nginx proxy to use a consistent frontend/backend container with the websockets ?

6

You might want to check the ip_hash directive of the upstream block.

Honestly sticky sessions are so 2010… modern applications typicaly store their session state in a key/values store, set the reverse proxy or load balancer to spread traffic evenly amongst the replicas, and let the application fetch existing sessions from the key/value store and push updates back to them.