nginx conf used by Foursquare's artifact cache

nginx.conf

# NOTE: 2 cpu cores
worker_processes 2;

error_log /data/log/nginx/error.log;

events {
  # NOTE: Accept as many connections as possible, after nginx gets notification about a new connection.
  # May flood worker_connections, if that option is set too low.
  multi_accept on;
  # NOTE: ulimit -n
  worker_connections  63536;
}

http {
  upstream backend {
    hash $request_uri consistent;
    server ${SERVER1};
    server ${SERVER2};
    server ${SERVER3};
  }

  client_max_body_size 1g;

  server {
    listen       80;
    server_name  localhost;

    proxy_request_buffering off;
    # NOTE(this is the response)
    proxy_buffering off;

    location / {
      # NOTE: Set current host in order to possibly redirect a GET request in the upstream.
      proxy_set_header Pants-Proxy-Host $hostname;
      proxy_pass http://backend;
    }
  }

  server {
    listen       8080;
    server_name  localhost;

    client_body_temp_path /data/appdata/nginx/tmp 1 2;
    create_full_put_path on;
    dav_access group:rw all:r;
    dav_methods PUT DELETE;
    sendfile on;

    location / {
      # HACK: Nginx doesn't support logical operators.
      # The below code is equivalent to
      # `if (http_pants_proxy_host != NULL && $request_method = GET && $downStreamProxy != $hostname)`
      if ($request_method = GET) {
        set $downStreamProxy $http_pants_proxy_host;
      }
      if ($http_pants_proxy_host = '') {
        set $downStreamProxy $hostname;
      }
      if ($request_method = HEAD) {
        set $downStreamProxy $hostname;
      }
      if ($request_method = PUT) {
        set $downStreamProxy $hostname;
      }
      if ($downStreamProxy != $hostname) {
        return 307 http://$hostname:$server_port$request_uri;
      }
      root /data/appdata/nginx/pantscache;
      autoindex on;
    }
  }
}