nginx.conf

nginx.conf

# User and group that workers will use.
user nginx nginx;

# Number of NGINX workers. Usually it's set, at maximum, 1 worker per CPU core.
# If the server has 2+ CPU cores but it still does not receive many requests, 
# it's a good idea to keep the value to 1 so it will avoid creating idle processes.
worker_processes  2;

# NGINX's master process id.
pid /var/run/nginx.pid;

events {
  # How many client connections each worker can maintain at a time.
  worker_connections 1024;
  # Using epoll is less CPU intensive when you have to serve thousands of connections, because
  # instead of scanning all connections to see which file descriptor is ready to read/write,
  # it will only scan those which are active.
  # p.s.: It's only available in Linux kernels later than 2.6.
  use epoll;
}

# HTTP config module
http {
  
  ##
  # MIME-TYPE
  ##

  # You can include other config files using the "include" directive.
  # Here we are including the mime-types, for example.
  include /etc/nginx/mime.types;
  # The "application/octet-stream" means that the response is a binary file.
  # If this directive is not defined then response will be set to "text/plain" by default.
  default_type  application/octet-stream;

  ##
  # LOG
  ##

  # Log format. Other NGINX variables ($variable) can be used as you wish.
  log_format main '$remote_addr - $remote_user [$time_local] '
                  '"$request" $status  $body_bytes_sent "$http_referer" '
                  '"$http_user_agent" "$http_x_forwarded_for"';
  # Access log: path and type.
  access_log  /var/log/nginx_access.log  main;
  # Error log: path and type.
  error_log  /var/log/nginx_error.log debug;

  ##
  # TCP
  ##

  # Optimizes data transfer copying data between one file descriptor and another
  # instead of reading and copying data to/from user space.
  sendfile on;
  # Causes NGINX to attempt to send its HTTP response head in one packet,
  # instead of using partial frames. This is useful for prepending headers before calling sendfile,
  # or for throughput optimization.
  tcp_nopush on;
  # Disables the Nagle algorithm.
  # It's useful for sending frequent small bursts of data in real time.
  tcp_nodelay  off;
  # Timeout during which a keep-alive client connection will stay open to serve 
  # all the requested files from the server side.
  keepalive_timeout  30s;
  # If a client does not receive anything within the time set in this directive, a connection is closed. 
  send_timeout 60s;

  ##
  # GZIP
  ##

  # In production you MUST set gzip to "on" in order to save bandwidth. Web browsers
  # which handle compressed files (all recent ones do) will get a very smaller version
  # of the server response. 
  gzip  on;
  # Enables compression for a given HTTP request version.
  gzip_http_version 1.0;
  # Compression level 1 (fastest) to 9 (slowest).
  gzip_comp_level 6;
  # Enables compression for all proxied requests.
  gzip_proxied any;
  # Minimum length of the response (bytes). Responses shorter than this length will not be compressed.
  gzip_min_length 10000;
  # Enables compression for additional MIME-types.
  gzip_types  text/plain text/css application/x-javascript text/xml
              application/xml application/xml+rss text/javascript;
  # Disables gzip compression for User-Agents matching the given regular expression.
  # Is this case we've disabled gzip for old versions of the IE that don't support compressed responses.
  gzip_disable "MSIE [1-6] \.";

  # Load modular configuration files from the /etc/nginx/conf.d directory.
  include /etc/nginx/conf.d/*.conf;

  ##
  # CLUSTERS
  ##

  # Below the "upstream" is defining some Thin clusters that are serving a Rails app.
  # They will handle the requets proxied by NGINX.
  upstream thin {
     server   0.0.0.0:3000;
     server   0.0.0.0:3001;
     # Here's a quick example of how you can load balance the requests among the clusters
     # applying the "weight" option to be used by the Round-robin algorithm.
     server   0.0.0.0:3002 weight=2;
  }
  
  # Example using Unix sockets.
  upstream puma {
    server unix:///var/run/puma.sock;
  }

  ##
  # VHOSTS
  ##

  # NGINX's virtual host.
  server {
    # Port to listen on.
    listen 80;
    
    # Sets the max size for file uploads to 20Mb.
    client_max_body_size 20M;

    # You can point the domain(s) served by this virtual host.
    server_name www.myawesomesite.com myawesomesite.com ec2-xx-xxx-xx-xxx.us-west-2.compute.amazonaws.com;

    # VHost specific access log.
    access_log  /var/log/nginx.vhost.access.log  main;

    location / {
      # Root directory from your application.
      root /var/www/myawesomesite/current/public;
      
      # Checks for the existence of files in order, and returns the first file that is found. 
      try_files $uri $uri/ /index.html;

      # Forward user's IP address to Rails app.
      proxy_set_header  X-Real-IP  $remote_addr;

      # If the file exists as a static file, it won't check the other conditionals 
      if (-f $request_filename) { 
        break; 
      }

      # Checks for index.html then rewrite
      # the URL to add "/index.html" to the end of it.
      if (-f $request_filename/index.html) {
        rewrite (.*) $1/index.html break;
      }

      # Append the ".html" to the end of the URL and then checks
      # the file system for that file. If it exists, then it
      # rewrites the URL to have explicit ".html" on its end.
      if (-f $request_filename.html) {
        rewrite (.*) $1.html break;
      }

      # If there is no file on the file system then it sets all the 
      # necessary headers and proxies to the Thin upstream.
      if (!-f $request_filename) {
        # Here's where the magic happens!
        proxy_pass http://thin;
        # Uncomment or define another virtual horst (server directive)
        # to serve and test the upstream w/ Unix sockets.
        # proxy_pass http://puma; 
        break;
      }
    }

    # Defines the static page for HTTP status 404
    error_page 404 /var/www/myawesomesite/current/public/404.html;
    # Defines the static page for HTTP status 40x
    location = /40x.html {
      root /usr/share/nginx/html;
    }

    # Defines the static page for HTTP status 500
    error_page 500 /var/www/myawesomesite/current/public/500.html;
    # Defines the static page for HTTP status 50x
    location = /50x.html {
      root /usr/share/nginx/html;
    }
  }
}