From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C11F4450EC for ; Tue, 17 Oct 2023 15:50:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ieCl5oaD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1372DC433CA; Tue, 17 Oct 2023 15:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697557854; bh=tpaDDi5AOX5s2f2Vf6+2CZRZFhSqTVVlwCWOfzHW5xo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ieCl5oaDAxZkxOYtHjwg/niu8JeeJEiIRgxDpG6oSFZG8E8/JhCDzqPpslpyNt+cL 2W5ZdJHtl7mDcg6WzQWGyd2vyDCEaa2Xu7vqs5nh+oKZyiB61LEJLDc6WxaOlQ8pVs L3joF9M+eS/bmroCblOlYZsUEfX+f3sasypbImnrvGuTeLLyZrYKOnOS3aapryxYQV mQsyCxke2Nu+J2tstXiJlo4fLdV3xMHwWrNUGb9TLg7tWEmml8zUe2/Iwh2ANPSbTq 5Eg2SueR6V5AAR5kqlLKzgCW0YCsVde28cRYiRacNQJFVMxo15FDX6pw5YpZquNpS7 ekTzYIA5fEbNw== Date: Tue, 17 Oct 2023 08:50:53 -0700 From: Jakub Kicinski To: Jiri Pirko Cc: netdev@vger.kernel.org, pabeni@redhat.com, davem@davemloft.net, edumazet@google.com Subject: Re: [patch net-next v2] tools: ynl: introduce option to process unknown attributes or types Message-ID: <20231017085053.63d4af40@kernel.org> In-Reply-To: References: <20231016110222.465453-1-jiri@resnulli.us> <20231016175903.605f61aa@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 17 Oct 2023 08:18:13 +0200 Jiri Pirko wrote: > Tue, Oct 17, 2023 at 02:59:03AM CEST, kuba@kernel.org wrote: > >On Mon, 16 Oct 2023 13:02:22 +0200 Jiri Pirko wrote: > >> +class FakeSpecAttr: > >> + def __init__(self, name): > >> + self.dict = {"name": name, "type": None} > >> + self.is_multi = False > >> + > >> + def __getitem__(self, key): > >> + return self.dict[key] > >> + > >> + def __contains__(self, key): > >> + return key in self.dict > > > >Why the new class? Why not attach the NlAttr object directly? > > It's not NlAttr, it's SpecAttr. And that has a constructor with things I > cannot provide for fake object, that's why I did this dummy object. Just to be able to do spec["type"] on it? There is an if "ladder", just replace the first if attr_spec["type"] == ... with if attr_spec is None: # your code elif attr_spec["type"] == ... hm? > >I have an idea knocking about in my head to support "polymorphic" > >nests (nests where decoding depends on value of another attr, > >link rtnl link attrs or tc object attrs). The way I'm thinking > >about doing it is to return NlAttr / struct nla_attr back to the user. > >And let the users call a sub-parser of choice by hand. > > Sounds parallel to this patch, isn't it? I'm just giving you extra info to explain my thinking. Given how we struggle to understand each other lately :S > >So returning a raw NlAttr appeals to me more. > > Wait, you suggest not to print out attr.as_bin(), but something else? Yea, it should not be needed. NlAttr has a __repr__ which *I think* should basically do the same thing? Or you may need to call that __repr__ from __str__, I don't know what PrettyPrinter uses internally > >> + if not self.process_unknown: > >> + raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}') > >> + if attr._type & Netlink.NLA_F_NESTED: > >> + subdict = self._decode(NlAttrs(attr.raw), None) > >> + decoded = subdict > >> + else: > >> + decoded = attr.as_bin() > > > >Again, I wouldn't descend at all. > > I don't care that much. I just thought it might be handy for the user to > understand the topology. Actually, I found it quite convenient already. > It's basically a direct dump. What is the reason not to do this exactly? No strong reason but you need to rewrite it to at least not access attr._type directly. I have a weak preference for putting this code in NlAttr's __repr__, could be more broadly useful?