backend web01 {
  .host = "192.168.30.101";
  .port = "80";
  .connect_timeout = 1s;
  .first_byte_timeout = 5s;
  .probe = {
    .url = "/";
    .timeout  = 10s;
    .interval = 30s;
    .window = 2;
    .threshold = 2;
  }
}

backend web02 {
  .host = "192.168.30.102";
  .port = "80";
  .connect_timeout = 1s;
  .first_byte_timeout = 5s;
  .probe = {
    .url = "/";
    .timeout  = 10s;
    .interval = 30s;
    .window = 2;
    .threshold = 2;
  }
}

backend web03 {
  .host = "192.168.30.103";
  .port = "80";
  .connect_timeout = 1s;
  .first_byte_timeout = 5s;
  .probe = {
    .url = "/";
    .timeout  = 10s;
    .interval = 30s;
    .window = 2;
    .threshold = 2;
  }
}


director web_cluster round-robin {
 { .backend = web01; }
 { .backend = web02; }
 { .backend = web03; }
}

#deflate logic ~ call normalize_deflate;
sub normalize_deflate {
  if (req.http.Accept-Encoding) {
    if (req.http.Accept-Encoding ~ "gzip") {
      set req.http.Accept-Encoding = "gzip";
    }
    elsif (req.http.Accept-Encoding ~ "deflate") {
      set req.http.Accept-Encoding = "deflate";
    }
    else {
      remove req.http.Accept-Encoding;
    }
  }
}

#normalize request to be cached ~ call recv_cache_prep;
sub recv_cache_prep {
  unset req.http.cookie;
  unset req.http.user-agent;
  return(lookup);
}

#normalize response to be cached ~ call fetch_cache_prep;
sub fetch_cache_prep {
  unset beresp.http.last-modified;
  unset beresp.http.set-cookie;
  unset beresp.http.expires;
  unset beresp.http.etag;
  set beresp.http.cache-control = "max-age = 3600";
}

#set our objects to brand new and add our X-cache header
sub vcl_deliver {
  set resp.http.age = "0";
  if (obj.hits > 0) {
    set resp.http.X-Cache = "m: HIT " obj.hits;
  }
  else {
    set resp.http.X-Cache = "m: MISS";
  }
}

#restart if we can't get a valid response
sub vcl_error {
  if (obj.status == 503 && req.restarts >= 5) {
    restart;
  }
}

sub vcl_recv {

  set req.http.X-Forwarded-For = client.ip;

  #misc settings
  set req.grace = 1h;

  #deflate logic
  call normalize_deflate;

  #set our backend
  set req.backend = web_cluster;

  #static files
  if (req.url ~ "^/[^?]+\.((?i)bmp|jpeg|jpg|png|gif|ico|js|css|txt|zip|swf|pdf)(\?.*|)$") {
    set req.url = regsub(req.url, "\?.*$", "");
    set req.http.X-v_cache = "file";
    call recv_cache_prep;
  }
  #no caching
  else {
    unset req.http.if-modified-since;
    return(pass);
  }

}

sub vcl_fetch {

  #misc settings
  set beresp.grace = 1h;

  #static file
  if (req.http.X-v_cache == "file") {
    call fetch_cache_prep;
    set beresp.ttl = 12h;
  }
  #don't cache 404's or redirects
  elsif (beresp.status == 404 || beresp.status == 302 || beresp.status == 301) {
    set beresp.cacheable = false;
    return(pass);
  }
  #no caching
  else {
    set beresp.cacheable = false;
    return(pass);
  }

}