From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <kostja.osipov@gmail.com>
Received: from mail-lj1-f194.google.com (mail-lj1-f194.google.com
 [209.85.208.194])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (No client certificate requested)
 by dev.tarantool.org (Postfix) with ESMTPS id 0AE434696C3
 for <tarantool-patches@dev.tarantool.org>;
 Tue, 24 Mar 2020 23:02:18 +0300 (MSK)
Received: by mail-lj1-f194.google.com with SMTP id s13so48521ljm.1
 for <tarantool-patches@dev.tarantool.org>;
 Tue, 24 Mar 2020 13:02:18 -0700 (PDT)
Date: Tue, 24 Mar 2020 23:02:16 +0300
From: Konstantin Osipov <kostja.osipov@gmail.com>
Message-ID: <20200324200216.GA18984@atlas>
References: <cover.1585053742.git.lvasiliev@tarantool.org>
 <7982fc7b062b2424689a990de1f76ca2ff0e4f50.1585053743.git.lvasiliev@tarantool.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <7982fc7b062b2424689a990de1f76ca2ff0e4f50.1585053743.git.lvasiliev@tarantool.org>
Subject: Re: [Tarantool-patches] [PATCH 3/6] iproto: Add negotiation phase
List-Id: Tarantool development patches <tarantool-patches.dev.tarantool.org>
List-Unsubscribe: <https://lists.tarantool.org/mailman/options/tarantool-patches>, 
 <mailto:tarantool-patches-request@dev.tarantool.org?subject=unsubscribe>
List-Archive: <https://lists.tarantool.org/pipermail/tarantool-patches/>
List-Post: <mailto:tarantool-patches@dev.tarantool.org>
List-Help: <mailto:tarantool-patches-request@dev.tarantool.org?subject=help>
List-Subscribe: <https://lists.tarantool.org/mailman/listinfo/tarantool-patches>, 
 <mailto:tarantool-patches-request@dev.tarantool.org?subject=subscribe>
To: Leonid Vasiliev <lvasiliev@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org

* Leonid Vasiliev <lvasiliev@tarantool.org> [20/03/24 16:02]:
> The negotiation phase has been added to IPROTO
> 
> For possibility to have a custom parameters of session the negotiation
> phase has been added. This is necessary to enable the transmission of
> an error in different formats(depending on the choice of the client).
> 
> @TarantoolBot document
> Title: IPROTO: The negatiation phase
> For backward compatibility of the data transmission format,
> the negotiation phase has been added to IPROTO.
> A new key (IPROTO_NEGOTIATION) has been added to IPROTO command codes.
> NEGOTIATION BODY: CODE = 0x0E
> +==========================+
> |                          |
> |  NEGOTIATION PARAMETERS  |
> |                          |
> +==========================+
>            MP_MAP
> Session negotiation parameters are a map with keys like ERROR_FORMAT_VERSION ...
> The response is a map with all stated negotiation parameters.
> So, for work with the new format of errors, it is necessary to perform the negotiation phase,
> otherwise errors will be transmitted in the old format (by default).

Why not make it a key in IPROTO_AUTH, and require a separate
round-trip?

Why have it at all and not look at server version, which is part
of the greeting already?

-- 
Konstantin Osipov, Moscow, Russia