From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <w.bumiller@proxmox.com>
Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68])
 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
 key-exchange X25519 server-signature RSA-PSS (2048 bits))
 (No client certificate requested)
 by lists.proxmox.com (Postfix) with ESMTPS id EB4C761442
 for <pbs-devel@lists.proxmox.com>; Fri, 18 Feb 2022 16:27:56 +0100 (CET)
Received: from firstgate.proxmox.com (localhost [127.0.0.1])
 by firstgate.proxmox.com (Proxmox) with ESMTP id E2CF32B61A
 for <pbs-devel@lists.proxmox.com>; Fri, 18 Feb 2022 16:27:56 +0100 (CET)
Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com
 [94.136.29.106])
 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
 key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256)
 (No client certificate requested)
 by firstgate.proxmox.com (Proxmox) with ESMTPS id 7A10D2B610
 for <pbs-devel@lists.proxmox.com>; Fri, 18 Feb 2022 16:27:56 +0100 (CET)
Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1])
 by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 538FC46DFD
 for <pbs-devel@lists.proxmox.com>; Fri, 18 Feb 2022 16:27:56 +0100 (CET)
Date: Fri, 18 Feb 2022 16:27:55 +0100
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
To: Dietmar Maurer <dietmar@proxmox.com>
Cc: Proxmox Backup Server development discussion <pbs-devel@lists.proxmox.com>, 
 Dominik Csapak <d.csapak@proxmox.com>
Message-ID: <20220218152755.4s5zdu7xutje7kxw@wobu-vie.proxmox.com>
References: <464675824.1190.1645169765999@webmail.proxmox.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <464675824.1190.1645169765999@webmail.proxmox.com>
X-SPAM-LEVEL: Spam detection results:  0
 AWL 0.384 Adjusted score from AWL reputation of From: address
 BAYES_00                 -1.9 Bayes spam probability is 0 to 1%
 KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment
 SPF_HELO_NONE           0.001 SPF: HELO does not publish an SPF Record
 SPF_PASS               -0.001 SPF: sender matches SPF record
 T_SCC_BODY_TEXT_LINE    -0.01 -
Subject: Re: [pbs-devel] [RFC PATCH proxmox 1/4] proxmox-async: add
 SenderWriter helper
X-BeenThere: pbs-devel@lists.proxmox.com
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Proxmox Backup Server development discussion
 <pbs-devel.lists.proxmox.com>
List-Unsubscribe: <https://lists.proxmox.com/cgi-bin/mailman/options/pbs-devel>, 
 <mailto:pbs-devel-request@lists.proxmox.com?subject=unsubscribe>
List-Archive: <http://lists.proxmox.com/pipermail/pbs-devel/>
List-Post: <mailto:pbs-devel@lists.proxmox.com>
List-Help: <mailto:pbs-devel-request@lists.proxmox.com?subject=help>
List-Subscribe: <https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel>, 
 <mailto:pbs-devel-request@lists.proxmox.com?subject=subscribe>
X-List-Received-Date: Fri, 18 Feb 2022 15:27:57 -0000

On Fri, Feb 18, 2022 at 08:36:05AM +0100, Dietmar Maurer wrote:
> This can block the executor? If so, should we use block_in_place?
> Or does self.sender.blocking_send() consider that automatically?

The sender in this case is a thread. The tokio side is the receiver.

The type implements `Write` which is blocking by definition, adding a
`block_in_place` inside it is never correct.

If mixing of blocking/async code is really a concern (which I don't
think it is), I'd rather not expose `from_sender` (or under a different
name as an `unsafe fn`) and instead only have a function creating the
*tuple* of `(SenderWriter, Receiver)` with appropriate documentation
about the sync/async nature of the two sides.

But I don't think this is truly warranted.