SSE / EventSource closes after first chunk of data (Rails 4 + Puma + Nginx)

Question

I followed the 401-ActionController-Live Railscast and this Blog Post about Server-Sent-Events to set up something similar in my Rails app. It works perfectly when I open connections to the server when only using puma but with puma + nginx, the connection closes after the first chunk of data is sent.

I also tried following the solutions provided in these questions but they didn't work for me:

• ActionController::Live Streaming dies after first chunk sent
• EventSource / Server-Sent Events through Nginx

This is what I'm getting:

This is How I set up my Server and this is my current nginx configuration:

upstream puma {
  server unix:///home/deploy/apps/outy/shared/tmp/sockets/outy-puma.sock;
  keepalive 16;
}

server {
  listen 80 default_server deferred;

  root /home/deploy/apps/outy/current/public;
  access_log /home/deploy/apps/outy/current/log/nginx.access.log;
  error_log /home/deploy/apps/outy/current/log/nginx.error.log info;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @puma;
  location @puma {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;

    proxy_pass http://puma;

    proxy_http_version 1.1;
    proxy_set_header Connection "";
    proxy_buffering off;
    proxy_cache off;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 10M;
  keepalive_timeout 10;
}

Answer 1

I will share configuration that worked.

nginx

upstream app_server {
    server unix:/var/tmp/sockets/puma.sock
    fail_timeout=0;
}

server {
    listen 80 default_server;
    listen 443 ssl;
    client_max_body_size 8m;
    server_tokens off;

    server_name localhost;

    keepalive_timeout 5;

    location / {
        try_files @uri @app;
    }

    location @app {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $http_x_forwarded_proto;
      proxy_set_header Host $http_host;
      proxy_redirect off;

      proxy_http_version 1.1;
      chunked_transfer_encoding off;

      proxy_buffering off;

      proxy_pass http://app_server;
    }
}

controller

class StreamController < ActionController::Base
  include ActionController::Live

  def hello
    response.headers["Content-Type"] = "text/event-stream" #; charset=utf-8"

    10.times {
      response.stream.write("data: Hello World!!\n\n")
      sleep 1
    }
  rescue IOError
    puts "Stream IO Error"
    logger.info "Stream IO Error"
  ensure
    puts "Stream closed"
    logger.info "Stream closed"
    response.stream.close
  end
end

curl

$ curl -i -N http://localhost/stream/hello
HTTP/1.1 200 OK
Server: nginx
Date: Wed, 29 Jul 2015 09:15:43 GMT
Content-Type: text/event-stream
Transfer-Encoding: chunked
Connection: keep-alive
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
Cache-Control: no-cache
X-Request-Id: 41e80567-d792-4a48-9ec3-c661aa056081
X-Runtime: 0.062282
Vary: Origin

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!

data: Hello World!!