gistfile1.h

# Setup our director and configure the two backends
director doctype_director round-robin {
  { 
    .backend = { 
      .host = "172.20.0.70"; 
      .port = "http";
      .probe = {
        .url = "/lbcheck/lbuptest";
        .timeout = 0.3 s;
        .window = 8;
        .threshold = 3;
      }
    }
  } 
  {
    .backend = { 
      .host = "172.20.2.214"; 
      .port = "http";
      .probe = {
        .url = "/lbcheck/lbuptest";
        .timeout = 0.3 s;
        .window = 8;
        .threshold = 3;
      }
    }
  }
}


sub vcl_recv {
  
  # Grace will cache if the backends are down - if all the backends are down then the
  # cache will not clear for 1 hour thus hopefully keeping the read only part of the site up
  if (req.backend.healthy) {
    set req.grace = 30s;
  } else {
    set req.grace = 1h;
  }
  
  # Skip any requests to the load balancer test
  if (req.url ~ "^/lbcheck/lbuptest$") {
    return (pass);
  }
  
  # Normalize accept-encoding headers
  # Some browsers will capitalise, include multiple Accept-Encoding options etc.
  # In order to reduce the number of caches we keep with different encodings,
  # normalize this header here.
  if (req.http.Accept-Encoding) {
    if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$") {
      # No point in compressing these
      remove req.http.Accept-Encoding;
  } elsif (req.http.Accept-Encoding ~ "gzip") {
      set req.http.Accept-Encoding = "gzip";
  } elsif (req.http.Accept-Encoding ~ "deflate") {
      set req.http.Accept-Encoding = "deflate";
  } else {
    # unkown algorithm
    remove req.http.Accept-Encoding;
    }
  }
  
  # Normalize the Host: header
  # This ensures for caching purposes that all urls are seen as "doctype.com/uri"
  # even if this is an asset request to assets1.doctype.com/uri
  # ensure's we don't cache static assets multiple times
  if (req.http.host ~ "^(assets\d\.)+doctype.com$") {
     set req.http.host = "doctype.com";
  }
  
  # This is where we decide on whether to cache or not
  # Cache any images, javascript, css and remove any cookies
  # Skip the cache if the user has the user_credentials cookie
  # Skip the cache if the user is hitting a url where we'd like cookies
  # Skip the cache if its not a GET or HEAD request
  # Otherwise, bin the cookie and lookup in the cache
  if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
    unset req.http.cookie;
    lookup;
  } else {
    if (req.http.cookie ~ "user_credentials") {
      pass;
    } elsif (req.url ~ "^/login") {
      pass;
    } elsif (req.url ~ "^/activate") {
      pass;
    } elsif (req.url ~ "^/sessions") {
      pass;
    } elsif (req.url ~ "^/users/new") {
      pass;
    } elsif (req.url ~ "^/users") {
      pass;
    } elsif (req.url ~ "^/password_resets") {
      pass;
    } elsif (req.request != "GET" && req.request != "HEAD") {
      pass;
    } else {
      unset req.http.cookie;
    }
  }
  
}

sub vcl_fetch {

  # See vcl_recv

  set obj.grace = 1h;
  
  # cache CSS and JS files
  if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
    unset obj.http.Set-Cookie;
  }	

  if (req.http.cookie ~ "user_credentials") {
    pass;
  } elsif (req.url ~ "^/login") {
    pass;
  } elsif (req.url ~ "^/activate") {
    pass;
  } elsif (req.url ~ "^/sessions") {
    pass;
  } elsif (req.url ~ "^/users/new") {
    pass;
  } elsif (req.url ~ "^/users") {
    pass;
  } elsif (req.url ~ "^/password_resets") {
    pass;
  } elsif (req.request != "GET" && req.request != "HEAD") {
    pass;
  } else {
    unset obj.http.Set-Cookie;
  }
  
  # If this is a 40x error, skip the cache
  if (obj.status >=400 && obj.status <500) {
    pass;
  }

  # If this is a 50x error, skip the cache
  if (obj.status >=500 && obj.status <600) {
    pass;
  }

}

sub vcl_deliver {
  # Neat little helper for checking you got caching right
  # Adds an X-Cache: header to your http requests which says either
  # HIT or MISS to indicate if the request was cached by varnish
  if (obj.hits > 0) {
          set resp.http.X-Cache = "HIT";
  } else {
          set resp.http.X-Cache = "MISS";
  }
}