From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 91895C001E0 for ; Thu, 27 Jul 2023 11:47:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qOyWn-0006Xo-NM; Thu, 27 Jul 2023 06:47:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qOyWl-0006Xf-Ps for qemu-devel@nongnu.org; Thu, 27 Jul 2023 06:47:27 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qOyWk-0003j0-5h for qemu-devel@nongnu.org; Thu, 27 Jul 2023 06:47:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690454845; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=gUh1dJfVuP+Tgn4Sa9PFuuQFXkAxBHH/fihyQQ25SAs=; b=Cmr9Riwv1xL3U1aSJeVV+1xa1UlX/CMH3vxmlBBkHod0msN1g/559P4dEYx/rWwfEhU4sF lTGGPsNvpd1qXFZcUAksAsqZcD3JP3MIpTwOR0dcn4zGFBqAhhGMS4+bt2VHfjmbw8e9bp ejzLx2kNdkOjFfsmbDPtVhAvNfeS+gc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-649-ZBpIjJzaM6iJlYuV1t_Rcg-1; Thu, 27 Jul 2023 06:47:23 -0400 X-MC-Unique: ZBpIjJzaM6iJlYuV1t_Rcg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8ABB8185A792 for ; Thu, 27 Jul 2023 10:47:23 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0115CC2C7D3; Thu, 27 Jul 2023 10:47:22 +0000 (UTC) Date: Thu, 27 Jul 2023 11:47:20 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: John Snow Cc: Paolo Bonzini , qemu-devel Subject: Re: Implementing "tee" in python asyncio Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Jul 26, 2023 at 04:25:34PM -0400, John Snow wrote: > Hi folks, > > I'm currently wondering how to take a StreamReader as found on > https://docs.python.org/3/library/asyncio-subprocess.html#asyncio.subprocess.Process > and to consume the data while optionally re-streaming it to a > secondary consumer. > > What I'd like to do is create a StreamWatcher class that consumes > console data while optionally logging to python logging and/or a file; > but re-buffers the data into an async stream where an additional > consumer is free to use the "standard asyncio API" to consume console > data at their leisure in a way that's unsurprising. > > What I'd like this *for* is to be able to do aggressive logging of > stdout/stderr and console data without denying tests the ability to > consume the data as they see fit for their testing purposes. I want to > have my cake and eat it too, and we don't do a good job of managing > this consistently across the board. > > I am wondering if there's any way around creating a literal socketpair > and suffering the creation of a full four StreamReader/StreamWriter > instances (one pair per socket...) and then just hanging on to the > "unused" reader/writer per each. It seems kind of foolishly excessive. > It also seems like it might be a pain in the butt if I want > cross-platform compatibility with windows for the machine appliance. > > Anyone got any bright ideas? Don't bother with any of the above, just add 'logfile=/path/to/log' to the -chardev argument. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|