gistfile1.txt

backend test1 {
        .port = "80";
        .host = "***";
        .probe = {
                .url = "http://***/health.php";
                .interval = 10s;
                .timeout = 10s;
                .window = 6;
                .threshold = 4;
        }
        .first_byte_timeout = 120s;
        .between_bytes_timeout = 240s;
}

backend test2 {
        .port = "80";
        .host = "***";
        .probe = {
                .url = "http://***/health.php";
                .interval = 10s;
                .timeout = 10s;
                .window = 6;
                .threshold = 4;
        }
        .first_byte_timeout = 120s;
        .between_bytes_timeout = 240s;
}

director director_test round-robin {
	{
		.backend = test1;
	}
	{
		.backend = test2;
	}
}

sub vcl_recv {	
	if (
		req.http.host == "test.***.com"
	) {

		# Grab the backend cookie in case we need to route explicitly.
		if (req.http.Cookie ~ "BACKEND=") {
			set req.http.X-BACKEND = regsub(req.http.Cookie, "^.*BACKEND=([^;]*).*$", "\1");
		}

		if
		# Specific backends.
		(req.http.X-BACKEND ~ "^test1$") {
			set req.backend = test1;
		}
		else if
		(req.http.X-BACKEND ~ "^test2$") {
			set req.backend = test2;
		}
		else if
		# Load balancer.
		(1==1) {
			set req.backend = director_test;
		}

    		unset req.http.X-BACKEND;

    		# Redirect to another backend. Force session restart.
		if (!req.backend.healthy && req.backend != director_test) {
			set req.backend = director_test;
			set req.http.Cookie = regsub(req.http.Cookie, "PHPSESSID=[^;]*;?", "");
			set req.http.Cookie = regsub(req.http.Cookie, "SECSESSID=[^;]*;?", "");
			set req.http.Cookie = regsub(req.http.Cookie, "BACKEND=[^;]*;?", "");
    }

	}
}

sub vcl_fetch {

	if (
		req.http.host == "test.***.com"
	) {

		set beresp.http.X-PHPSESSID = header.get(beresp.http.Set-Cookie, "PHPSESSID=");
		set beresp.http.X-SECSESSID = header.get(beresp.http.Set-Cookie, "SECSESSID=");
		set beresp.http.X-COOKIE-SENT = "0";

		# Intercept session and add BACKEND Set-Cookie as appropriate.
		if (beresp.http.X-PHPSESSID!="" || beresp.http.X-SECSESSID!="") {
			if (beresp.http.X-PHPSESSID~"deleted" || beresp.http.X-SECSESSID~"deleted") {
				# Try to cleanup backend cookie. Unfortunately this could remove BACKEND in error
				# if there is more than one session Set-Cookie - we can't interate through cookies.
				header.append(beresp.http.Set-Cookie, "BACKEND=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/; HttpOnly");
			} else {
				header.append(beresp.http.Set-Cookie, "BACKEND=" + beresp.backend.name + "; path=/; HttpOnly");
				set beresp.http.X-COOKIE-SENT = "1";
			}
		}

		# Fix the situation where the client thinks she has a session, but BACKEND is missing.
		if (!req.http.Cookie ~ "BACKEND=" && beresp.http.X-COOKIE-SENT=="0") {
			if (req.http.Cookie ~ "PHPSESSID=" || req.http.Cookie ~ "SECSESSID=") {
				header.append(beresp.http.Set-Cookie, "BACKEND=" + beresp.backend.name + "; path=/; HttpOnly");
			}
		}

		unset beresp.http.X-PHPSESSID;
		unset beresp.http.X-SECSESSID;
		unset beresp.http.X-COOKIE-SENT;

	}

}

sub vcl_fetch {

	if (
		req.http.host == "test.***.com"
	) {

		set beresp.http.X-PHPSESSID = header.get(beresp.http.Set-Cookie, "PHPSESSID=");
		set beresp.http.X-SECSESSID = header.get(beresp.http.Set-Cookie, "SECSESSID=");
		set beresp.http.X-COOKIE-SENT = "0";

		# Intercept session and add BACKEND Set-Cookie as appropriate.
		if (beresp.http.X-PHPSESSID!="" || beresp.http.X-SECSESSID!="") {
			if (beresp.http.X-PHPSESSID~"deleted" || beresp.http.X-SECSESSID~"deleted") {
				# Try to cleanup backend cookie. Unfortunately this could remove BACKEND in error
				# if there is more than one session Set-Cookie - we can't interate through cookies.
				header.append(beresp.http.Set-Cookie, "BACKEND=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/; HttpOnly");
			} else {
				header.append(beresp.http.Set-Cookie, "BACKEND=" + beresp.backend.name + "; path=/; HttpOnly");
				set beresp.http.X-COOKIE-SENT = "1";
			}
		}

		# Fix the situation where the client thinks she has a session, but BACKEND is missing.
		if (!req.http.Cookie ~ "BACKEND=" && beresp.http.X-COOKIE-SENT=="0") {
			if (req.http.Cookie ~ "PHPSESSID=" || req.http.Cookie ~ "SECSESSID=") {
				header.append(beresp.http.Set-Cookie, "BACKEND=" + beresp.backend.name + "; path=/; HttpOnly");
			}
		}

		unset beresp.http.X-PHPSESSID;
		unset beresp.http.X-SECSESSID;
		unset beresp.http.X-COOKIE-SENT;

	}

}