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 X-Spam-Level: X-Spam-Status: No, score=-12.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61C41C433DB for ; Wed, 20 Jan 2021 09:46:52 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 909B223131 for ; Wed, 20 Jan 2021 09:46:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 909B223131 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; 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bh=mYYtu+RTF1CcrtLtZ/kJ89yLwVMdzk0F0B02V77W3/A=; b=BTJxO4sdvr3jNn/qqP4K/CZ87dD+RAB0GX9Y4+5s4I/NrwvaRZW9sTNfGUkrC8TzwSNb2J dejAjL+9rXppSXdQIGtIpnWAcCCfLWJvbpnfPnAXRecvN300Tc4tN7vmMvlDPL0UNnpGtg eV+qWB3gmWfSbOvTLB0am5hJjeFTTPk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-247-k-pLgZHVMRKGajejgEDM9A-1; Wed, 20 Jan 2021 04:45:45 -0500 X-MC-Unique: k-pLgZHVMRKGajejgEDM9A-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AFCE71800D41; Wed, 20 Jan 2021 09:45:44 +0000 (UTC) Received: from redhat.com (ovpn-115-126.ams2.redhat.com [10.36.115.126]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2563D6F99D; Wed, 20 Jan 2021 09:45:42 +0000 (UTC) Date: Wed, 20 Jan 2021 09:45:39 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Dov Murik Subject: Re: [PATCH] qmp-shell: Suppress banner and prompt when stdin is not a TTY Message-ID: <20210120094539.GC3015589@redhat.com> References: <20210117072742.119377-1-dovmurik@linux.vnet.ibm.com> <1d63a097-27d5-5b3a-2ce6-f6a2402e135e@linux.vnet.ibm.com> MIME-Version: 1.0 In-Reply-To: <1d63a097-27d5-5b3a-2ce6-f6a2402e135e@linux.vnet.ibm.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.195, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: John Snow , qemu-devel@nongnu.org, Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jan 20, 2021 at 10:25:25AM +0200, Dov Murik wrote: > Hi John, > > On 19/01/2021 22:02, John Snow wrote: > > On 1/17/21 2:27 AM, Dov Murik wrote: > > > Detect whether qmp-shell's standard input is not a TTY; in such case, > > > assume a non-interactive mode, which suppresses the welcome banner and > > > the "(QEMU)" prompt.  This allows for easier consumption of qmp-shell's > > > output in scripts. > > > > > > Example usage before this change: > > > > > >      $ printf "query-status\nquery-kvm\n" | sudo > > > scripts/qmp/qmp-shell qmp-unix-sock > > >      Welcome to the QMP low-level shell! > > >      Connected to QEMU 5.1.50 > > > > > >      (QEMU) {"return": {"status": "running", "singlestep": false, > > > "running": true}} > > >      (QEMU) {"return": {"enabled": true, "present": true}} > > >      (QEMU) > > > > > > Example usage after this change: > > > > > >      $ printf "query-status\nquery-kvm\n" | sudo > > > scripts/qmp/qmp-shell qmp-unix-sock > > >      {"return": {"status": "running", "singlestep": false, > > > "running": true}} > > >      {"return": {"enabled": true, "present": true}} > > > > > > Signed-off-by: Dov Murik > > > > Hiya! I've been taking lead on modernizing a lot of our python > > infrastructure, including our QMP library and qmp-shell. > > > > (Sorry, not in MAINTAINERS yet; but I am in the process of moving these > > scripts and tools over to ./python/qemu/qmp.) > > Thanks for this effort. > > > > > This change makes me nervous, because qmp-shell is not traditionally a > > component we've thought of as needing to preserve backwards-compatible > > behavior. Using it as a script meant to be consumed in a headless > > fashion runs a bit counter to that assumption. > > > > I'd be less nervous if the syntax of qmp-shell was something that was > > well thought-out and rigorously tested, but it's a hodge-podge of > > whatever people needed at the moment. I am *very* reluctant to cement > > it. > > Yes, I understand your choice. > > > > > > Are you trying to leverage the qmp.py library from bash? > > Yes, I want to send a few QMP commands and record their output. If I use > socat to the unix-socket I need to serialize the JSON request myself, so > using qmp-shell saves me that; also not sure if there's any negotiation done > at the beginning by qmp-shell. There is a handshake, but it is just a single json message. See docs/interop/qmp-intro.txt and qmp-spec.txt for guidance. > Is there an easier way to script qmp commands, short of writing my own > python program which uses the qmp.py library? Yes, writing your own python program is probably best. Doing anything complex is shell is almost always a mistake, as it is a very crude and poor language compared to something like managing QEMU/QMP. Note that I don't believe that we've declared qmp.py to be a long term stable interface for users outside of QEMU either. An alternative is to just use the python sockets APIs directly to speak to QEMU/QMP 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 :|