Re:The Simplicity of Single-File Golang Deployments
by adql on Wednesday March 22, 2023 @12:20PM
(#35263404)
Same way you do with any other app not specifically designed for it; you start 2 copies of it and put loadbalancer in front of it. I did that via some systemd voodoo
But TECHNICALLY to do that in one without external proxy you'd need to figure out how to set SO_REUSEPORT for the web socket handler, then start the second one before the first.
You'd still have any ongoing connections cut unless you unbind socket and then finish any existing connection, which would be pretty hard with default http server.
I just put HAProxy instance on my VPS that does all of that, including only allowing traffic once app says "yes I am ok" in healthcheck. Then the app can have "shutting down" phase, where it reports "I am down" on healthcheck but still finished any active connections to the client.
But TECHNICALLY to do that in one without external proxy you'd need to figure out how to set SO_REUSEPORT for the web socket handler, then start the second one before the first.
Haven't actually tried it but someone apparently did: https://iximiuz.com/en/posts/go-net-http-setsockopt-example/
You'd still have any ongoing connections cut unless you unbind socket and then finish any existing connection, which would be pretty hard with default http server.
I just put HAProxy instance on my VPS that does all of that, including only allowing traffic once app says "yes I am ok" in healthcheck. Then the app can have "shutting down" phase, where it reports "I am down" on healthcheck but still finished any active connections to the client.