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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 2AFD6C11F64 for ; Thu, 1 Jul 2021 04:14:34 +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 82D1F6140B for ; Thu, 1 Jul 2021 04:14:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82D1F6140B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40430 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lyo5v-0002Pv-EW for qemu-devel@archiver.kernel.org; Thu, 01 Jul 2021 00:14:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42232) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lyo4w-0008C8-2x for qemu-devel@nongnu.org; Thu, 01 Jul 2021 00:13:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:33579) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lyo4t-0000ZW-0H for qemu-devel@nongnu.org; Thu, 01 Jul 2021 00:13:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625112804; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=cL7i5NZP5Udpu6OSOAfTtxf6q96tQZUE6D8xT1Aw7gA=; b=eAh860alSmV+5R3FZo19gqcxTD2+dMs1mZVbziDT5A6wbyztBojiBYOjbi7CX7iNETINm8 Dny2LxoKilLh4A7a10xAW0PHwmeSc1cxI4POiM3878i6jsInF7j7CCZyxleVIxVSBXVMgk 27KGNJwXRiQWacs27dQo7+m0hhu8wOA= 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-509-dPA2qvbqOxaMs4kS41rrHA-1; Thu, 01 Jul 2021 00:13:22 -0400 X-MC-Unique: dPA2qvbqOxaMs4kS41rrHA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A04D280415A; Thu, 1 Jul 2021 04:13:21 +0000 (UTC) Received: from scv.redhat.com (ovpn-118-71.rdu2.redhat.com [10.10.118.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2B712604CC; Thu, 1 Jul 2021 04:13:14 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org Subject: [PATCH 00/20] python: introduce Asynchronous QMP package Date: Thu, 1 Jul 2021 00:12:53 -0400 Message-Id: <20210701041313.1696009-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jsnow@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=216.205.24.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.435, 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_H4=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: , Cc: Eduardo Habkost , Eric Blake , Stefan Hajnoczi , Markus Armbruster , Wainer dos Santos Moschetta , "Niteesh G . S ." , Willian Rampazzo , Cleber Rosa , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" GitLab: https://gitlab.com/jsnow/qemu/-/commits/python-async-qmp-aqmp=0D CI: https://gitlab.com/jsnow/qemu/-/pipelines/330003554=0D Docs: https://people.redhat.com/~jsnow/sphinx/html/qemu.aqmp.html=0D Based-on: <20210701020921.1679468-1-jsnow@redhat.com>=0D [PULL 00/15] Python patches=0D =0D Hi!=0D =0D This patch series adds an Asynchronous QMP package to the Python=0D library. It offers a few improvements over the previous library:=0D =0D - out-of-band support=0D - true asynchronous event support=0D - avoids undocumented interfaces abusing non-blocking sockets=0D =0D This library serves as the basis for a new qmp-shell program that will=0D offer improved reconnection support, true asynchronous display of=0D events, VM and job status update notifiers, and so on.=0D =0D My intent is to eventually publish this library directly to PyPI as a=0D standalone package. I would like to phase out our usage of the old QMP=0D library over time; eventually replacing it entirely with this one.=0D =0D This series looks big by line count, but it's *mostly*=0D docstrings. Seriously!=0D =0D This package has *no* external dependencies whatsoever.=0D =0D Notes & Design=0D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=0D =0D Here are some notes on the design of how the library works, to serve as=0D a primer for review; however I also **highly recommend** browsing the=0D generated Sphinx documentation for this series.=0D =0D Here's that link again:=0D https://people.redhat.com/~jsnow/sphinx/html/qemu.aqmp.html=0D =0D The core machinery is split between the AsyncProtocol and QMP=0D classes. AsyncProtocol provides the generic machinery, while QMP=0D provides the QMP-specific details.=0D =0D The design uses two independent coroutines that act as the "bottom=0D half", a writer task and a reader task. These tasks run for the duration=0D of the connection and independently send and receive messages,=0D respectively.=0D =0D A third task, disconnect, is scheduled asynchronously whenever an=0D unrecoverable error occurs and facilitates coalescing of the other two=0D tasks.=0D =0D This diagram for how execute() operates may be helpful for understanding=0D how AsyncProtocol is laid out. The arrows indicate the direction of a=0D QMP message; the long horizontal dash indicates the separation between=0D the upper and lower half of the event loop. The queue mechanisms between=0D both dashes serve as the intermediaries between the upper and lower=0D half.=0D =0D +---------+=0D | caller |=0D +---------+=0D ^ |=0D | v=0D +---------+=0D +---------------> |execute()| -----------+=0D | +---------+ |=0D | |=0D [-----------------------------------------------------------]=0D | |=0D | v=0D +----+------+ +----------------+ +------+-------+=0D | ExecQueue | | EventListeners | |Outbound Queue|=0D +----+------+ +----+-----------+ +------+-------+=0D ^ ^ |=0D | | |=0D [-----------------------------------------------------------]=0D | | |=0D | | v=0D +--+----------------+---+ +-----------+-----------+=0D | Reader Task/Coroutine | | Writer Task/Coroutine |=0D +-----------+-----------+ +-----------+-----------+=0D ^ |=0D | v=0D +-----+------+ +-----+------+=0D |StreamReader| |StreamWriter|=0D +------------+ +------------+=0D =0D The caller will invoke execute(), which in turn will deposit a message=0D in the outbound send queue. This will wake up the writer task, which=0D well send the message over the wire.=0D =0D The execute() method will then yield to wait for a reply delivered to an=0D execution queue created solely for that execute statement.=0D =0D When a message arrives, the Reader task will unblock and route the=0D message either to the EventListener subsystem, or place it in the=0D appropriate pending execution queue.=0D =0D Once a message is placed in the pending execution queue, execute() will=0D unblock and the execution will conclude, returning the result of the RPC=0D call to the caller.=0D =0D Ugly Bits=0D =3D=3D=3D=3D=3D=3D=3D=3D=3D=0D =0D - MultiException is ... wonky. I am still working out how to avoid needing = it.=0D See patch 04/20 for details here, or see=0D https://people.redhat.com/~jsnow/sphinx/html/qemu.aqmp.error.html=0D =0D Patch 06/20 also goes into details of the ugliness; see=0D AsyncProtocol._results or view the same information here:=0D https://people.redhat.com/~jsnow/sphinx/html/_modules/qemu/aqmp/protocol.= html#AsyncProtocol._results=0D =0D - There are quite a few lingering questions I have over the design of the= =0D EventListener subsystem; I wrote about those ugly bits in excruciating de= tail=0D in patch 14/20.=0D =0D You can view them formatted nicely here:=0D https://people.redhat.com/~jsnow/sphinx/html/qemu.aqmp.events.html#experi= mental-interfaces-design-issues=0D =0D Patch Layout=0D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=0D =0D Patches 1-2 are tiny pylint configuration changes.=0D Patches 3-5 begin to check in Async QMP components, they are small.=0D Patches 6-11 add a generic async message-based protocol class,=0D AsyncProto. They are split as small as I could=0D reasonably split them.=0D Patches 12-14 check in more QMP-specific components.=0D Patches 15-18 add qmp_protocol.py, the new 'QMP' class. They're split as=0D far down as I could, I hope they're easy to review.=0D Patches 19-20 add a few finishing touches, they are small patches.=0D =0D Future Work=0D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=0D =0D These items are in progress:=0D =0D - A Synchronous QMP wrapper that allows this library to be easily used=0D from non-async code; this will also allow me to prove it works well by=0D demoing its replacement throughout iotests.=0D =0D - A QMP server class; to facilitate writing of unit tests.=0D =0D - Unit tests. Real unit tests.=0D =0D If you made it this far in the cover letter, congrats :)=0D =0D John Snow (20):=0D python/pylint: Add exception for TypeVar names ('T')=0D python/pylint: disable too-many-function-args=0D python/aqmp: add asynchronous QMP (AQMP) subpackage=0D python/aqmp: add error classes=0D python/aqmp: add asyncio compatibility wrappers=0D python/aqmp: add generic async message-based protocol support=0D python/aqmp: add runstate state machine to AsyncProtocol=0D python/aqmp: add logging to AsyncProtocol=0D python/aqmp: add AsyncProtocol.accept() method=0D python/aqmp: add _cb_inbound and _cb_inbound logging hooks=0D python/aqmp: add AsyncProtocol._readline() method=0D python/aqmp: add QMP Message format=0D python/aqmp: add well-known QMP object models=0D python/aqmp: add QMP event support=0D python/aqmp: add QMP protocol support=0D python/aqmp: Add message routing to QMP protocol=0D python/aqmp: add execute() interfaces=0D python/aqmp: add _raw() execution interface=0D python/aqmp: add asyncio_run compatibility wrapper=0D python/aqmp: add scary message=0D =0D python/qemu/aqmp/__init__.py | 61 +++=0D python/qemu/aqmp/error.py | 97 ++++=0D python/qemu/aqmp/events.py | 878 +++++++++++++++++++++++++++++++=0D python/qemu/aqmp/message.py | 207 ++++++++=0D python/qemu/aqmp/models.py | 133 +++++=0D python/qemu/aqmp/protocol.py | 851 ++++++++++++++++++++++++++++++=0D python/qemu/aqmp/py.typed | 0=0D python/qemu/aqmp/qmp_protocol.py | 565 ++++++++++++++++++++=0D python/qemu/aqmp/util.py | 183 +++++++=0D python/setup.cfg | 4 +-=0D 10 files changed, 2978 insertions(+), 1 deletion(-)=0D create mode 100644 python/qemu/aqmp/__init__.py=0D create mode 100644 python/qemu/aqmp/error.py=0D create mode 100644 python/qemu/aqmp/events.py=0D create mode 100644 python/qemu/aqmp/message.py=0D create mode 100644 python/qemu/aqmp/models.py=0D create mode 100644 python/qemu/aqmp/protocol.py=0D create mode 100644 python/qemu/aqmp/py.typed=0D create mode 100644 python/qemu/aqmp/qmp_protocol.py=0D create mode 100644 python/qemu/aqmp/util.py=0D =0D --=20=0D 2.31.1=0D =0D