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 95273C77B7C for ; Tue, 9 May 2023 14:40:48 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pwOVv-0006Du-Ux; Tue, 09 May 2023 10:40:28 -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 1pwOVo-00064H-Oz for qemu-devel@nongnu.org; Tue, 09 May 2023 10:40:24 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pwOVe-0000RJ-5C for qemu-devel@nongnu.org; Tue, 09 May 2023 10:40:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683643208; 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: in-reply-to:in-reply-to:references:references; bh=yRGdnBrikD5zWXjOu9JsNKjklL6n2i81Q1Bg9k0ULUc=; b=cMTVQZl6mSk/mSaazTu+X/hMGi83gsVvaXHgIDnJFVhxoLUHW+f/XBR0//DQLh2B1x2XOs GATBVO0FURyDvACQG/VBdXewO780vPLHfBVmW8qlzfpxd/Jd8zvNVDMEHQjrms3YwbRxMg MYlfyVg/4RMo2PCkvxxCgmFDJYYHvjc= 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-98-u0IoEXHIPiCBCG3Xb2kN3A-1; Tue, 09 May 2023 10:40:07 -0400 X-MC-Unique: u0IoEXHIPiCBCG3Xb2kN3A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B220A885628; Tue, 9 May 2023 14:40:06 +0000 (UTC) Received: from localhost (unknown [10.39.195.128]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1775263F84; Tue, 9 May 2023 14:40:05 +0000 (UTC) Date: Tue, 9 May 2023 10:40:04 -0400 From: Stefan Hajnoczi To: Mads Ynddal Cc: qemu-devel@nongnu.org, Cleber Rosa , John Snow , Mads Ynddal Subject: Re: [PATCH v2 05/12] simpletrace: Changed Analyzer class to become context-manager Message-ID: <20230509144004.GH1008478@fedora> References: <20230502092339.27341-1-mads@ynddal.dk> <20230502092339.27341-6-mads@ynddal.dk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="HaUXuIZmA7wrgRZO" Content-Disposition: inline In-Reply-To: <20230502092339.27341-6-mads@ynddal.dk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@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_H2=-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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --HaUXuIZmA7wrgRZO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 02, 2023 at 11:23:32AM +0200, Mads Ynddal wrote: > From: Mads Ynddal >=20 > Instead of explicitly calling `begin` and `end`, we can change the class > to use the context-manager paradigm. This is mostly a styling choice, > used in modern Python code. But it also allows for more advanced analyzers > to handle exceptions gracefully in the `__exit__` method (not > demonstrated here). >=20 > Signed-off-by: Mads Ynddal > --- > scripts/simpletrace.py | 40 +++++++++++++++++++++++----------------- > 1 file changed, 23 insertions(+), 17 deletions(-) >=20 > diff --git a/scripts/simpletrace.py b/scripts/simpletrace.py > index 7444a6e090..10ca093046 100755 > --- a/scripts/simpletrace.py > +++ b/scripts/simpletrace.py > @@ -121,12 +121,12 @@ def read_trace_records(event_mapping, event_id_to_n= ame, fobj): > =20 > yield rec > =20 > -class Analyzer(object): > +class Analyzer: > """A trace file analyzer which processes trace records. > =20 > - An analyzer can be passed to run() or process(). The begin() method= is > - invoked, then each trace record is processed, and finally the end() = method > - is invoked. > + An analyzer can be passed to run() or process(). The __enter__() me= thod is > + invoked when opening the analyzer using the `with` statement, then e= ach trace > + record is processed, and finally the __exit__() method is invoked. Bearing in mind compatibility with existing simpletrace analysis scripts, how about the following default method implementations? def __enter__(self): self.begin() def __exit__(self, exc_type, exc_val, exc_tb): if exc_type is None: self.end() return False Now simpletrace.py can switch to using the context manager and new scripts can implement __enter__()/__exit__(), while old scripts continue to work. > =20 > If a method matching a trace event name exists, it is invoked to pro= cess > that trace record. Otherwise the catchall() method is invoked. > @@ -152,19 +152,25 @@ def runstate_set(self, timestamp, pid, new_state): > ... > """ > =20 > - def begin(self): > + def __enter__(self): > """Called at the start of the trace.""" > - pass > + return self > =20 > def catchall(self, event, rec): > """Called if no specific method for processing a trace event has= been found.""" > pass > =20 > - def end(self): > + def __exit__(self, _type, value, traceback): > """Called at the end of the trace.""" > pass > =20 > -def process(events, log, analyzer, read_header=3DTrue): > + def __call__(self): > + """Fix for legacy use without context manager. > + We call the provided object in `process` regardless of it being = the object-type or instance. > + With this function, it will work in both cases.""" > + return self > + > +def process(events, log, analyzer_class, read_header=3DTrue): Please don't change the function signature since this is a public method and we should avoid breaking existing callers when possible. Instead of: with analyzer_class() as analyzer: we can use: with analyzer: ... --HaUXuIZmA7wrgRZO Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmRaW0QACgkQnKSrs4Gr c8hZiAgAvbQmHjIzu4I0OHHhSJUL9XqXrkO+2irnc1HRV5EEOpe+zk+B8OO+Uq10 2w8Hsg3ONlnADFyPkvTQQJZFep8j2TEUvWyo5t6pxyr3fGr7Gn4A7vdgo3rSKfrx S/LIIRfnV6HLN9wudy8GkAjb1tCzASyAD59v113CxA5PO5BmYqInap+qZReCBs9k lZffTGOBJMGd2Te2PejPcCamv3oQqlXpc7bShmmmy2QYDOYPTIcP0fS1Tr62FYP6 azu5zr8BIthvawp8ZtT6gNqj1bC4tLzcsdgyAzGR02nIomxZ79QqE4IczY6/sgjc qkiqssSPgntxrHMU9hV3SNV92/88DQ== =AEE9 -----END PGP SIGNATURE----- --HaUXuIZmA7wrgRZO--