From patchwork Fri Jun 17 12:19:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Victor Toso X-Patchwork-Id: 12885651 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 83E4BC433EF for ; Fri, 17 Jun 2022 12:24:04 +0000 (UTC) Received: from localhost ([::1]:40320 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o2B19-0004fm-Ls for qemu-devel@archiver.kernel.org; Fri, 17 Jun 2022 08:24:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46956) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o2Awy-0001MF-0g for qemu-devel@nongnu.org; Fri, 17 Jun 2022 08:19:44 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:31068) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o2Awt-0004yN-Gn for qemu-devel@nongnu.org; Fri, 17 Jun 2022 08:19:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655468377; 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=sw6ROPLVInqItqsM+G/Xyp9kYEgVxXiNkIUGYBPRgvQ=; b=CUkMvZYbSX6BBQfjuWaSg1y5jD56gKNZoVqukMTb3Pey+/X1FVN+robDRv/XegTP0ZXejM cNFDhQQM2janeda7+UEfZFgt7VnKqBN4xwRfgw0nKszLPtg7QGBaNFIdZF7rsBixkzd7ne m0viBi+UcpTxju7naYQI5jK8LhiyEv4= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-651-Swb-eOYqNbCl4dXy-WlCLQ-1; Fri, 17 Jun 2022 08:19:36 -0400 X-MC-Unique: Swb-eOYqNbCl4dXy-WlCLQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C95CA3C0D840 for ; Fri, 17 Jun 2022 12:19:35 +0000 (UTC) Received: from tapioca.redhat.com (unknown [10.40.192.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0F7D640334E; Fri, 17 Jun 2022 12:19:33 +0000 (UTC) From: Victor Toso To: qemu-devel@nongnu.org Cc: Eric Blake , Markus Armbruster , John Snow , Andrea Bolognani , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= Subject: [RFC PATCH v2 0/8] qapi: add generator for Golang interface Date: Fri, 17 Jun 2022 14:19:24 +0200 Message-Id: <20220617121932.249381-1-victortoso@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=victortoso@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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" Hi, This is the second iteration of RFC v1: https://lists.gnu.org/archive/html/qemu-devel/2022-04/msg00226.html # What this is about? To generate a simple Golang interface that could communicate with QEMU over QMP. The Go code that is generated is meant to be used as the bare bones to exchange QMP messages. The goal is to have this as a Go module in QEMU gitlab namespace, similar to what have been done to pyhon-qemu-qmp https://gitlab.com/qemu-project/python-qemu-qmp # Issues raised in RFC v1 The leading '*' for issues I addressed in this iteration * 1) Documentation was removed to avoid License issues, by Daniel Thread: https://lists.nongnu.org/archive/html/qemu-devel/2022-05/msg01889.html It is important for the generated Go module to be compatible with Licenses used by projects that would be using this. Copying the documentation of the QAPI spec might conflict with GPLv2+. I have not proposed another license in this iteration, but I'm planning to go with MIT No Attribution, aka MIT-0 [0]. Does it make sense to bind the generated code's license to MIT-0 already at generator level? [0] https://github.com/aws/mit-0/blob/master/MIT-0 2) Inconsistent generated Names, by Andrea + Markus Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-04/msg05026.html Example 1: | qapi | Go | Expected | | @logappend | Logappend | LogAppend | Example 2: (acronyms) VncInfo and DisplayReloadOptionsVNC This was not addressed in RFC v2 mainly because it seems to need more metadata support from the QAPI spec to handle specific scenarios. The solution seems either an extra metadata proposal by Andrea [1] or reviving Kevin's work [2] [1] https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg00127.html [2] https://lists.gnu.org/archive/html/qemu-devel/2021-09/msg04703.html * 3) Better type safety, by Andrea + Daniel Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg01906.html Most of the 'Any' type (interface {}) has been removed. The only place it still exists is for fields that uses QAPI's any type, like with command qom-set or the struct type ObjectPropertyInfo. * 4) QAPI enums mapped to String instead of Int type, by Daniel. Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg01904.html I'm still over the fence about using string here, mostly by the same issue reported here: https://gitlab.com/libvirt/libvirt-go-module/-/merge_requests/30#note_975517740 * 5) Events and Commands as interface, by Daniel Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg01914.html So, instead of having a Command/Event struct with a Any type for the Arguments (which could be set with SetPasswordCommand struct type for example); now we have a Command interface which all previous structs that behaved as Arguments implement. I've included Marshal{Command Event} and Unmarshal{Command Event} helper functions that operate on top of each interface. * 6) Removing Any from Unions, by Daniel Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg01912.html I basically followed the above suggestion to all other types that used Any. Specifically to unions were the removal of the 'discriminator' field, as proposed also in the above link. * 7) Flat structs by removing embed types. Discussion with Andrea Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg01590.html No one required it but I decided to give it a try. Major issue that I see with this approach is to have generated a few 'Base' structs that are now useless. Overall, less nested structs seems better to me. Opnions? Example: | /* This is now useless, should be removed? */ | type InetSocketAddressBase struct { | Host string `json:"host"` | Port string `json:"port"` | } | | type InetSocketAddress struct { | // Base fields | Host string `json:"host"` | Port string `json:"port"` | | | Numeric *bool `json:"numeric,omitempty"` | To *uint16 `json:"to,omitempty"` | Ipv4 *bool `json:"ipv4,omitempty"` | Ipv6 *bool `json:"ipv6,omitempty"` | KeepAlive *bool `json:"keep-alive,omitempty"` | Mptcp *bool `json:"mptcp,omitempty"` | } 8) Supporting multiple versions Thread: https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg02147.html I'm keen to working on the proposed solution above as it seems a good compromise to make code that can be compatible with multiple versions of qmp/qemu. But the basis needs to be defined first, so this is for the future. * 9) Handling { "error": { ... } } This was missing in the RFC v1. I've added a QapiError type that is included in all CommandReturn types, following Andrea's suggestion: https://lists.gnu.org/archive/html/qemu-devel/2022-04/msg02199.html # victortoso/qapi-go and victortoso/qemu I'm currently hosting the generated code from this RFCv2 at: https://gitlab.com/victortoso/qapi-go/-/tree/main/pkg/qapi This series can also be found at: https://gitlab.com/victortoso/qemu/-/commits/qapi-golang Thanks for taking a look, Victor Victor Toso (8): qapi: golang: Generate qapi's enum types in Go qapi: golang: Generate qapi's alternate types in Go qapi: golang: Generate qapi's struct types in Go qapi: golang: Generate qapi's union types in Go qapi: golang: Generate qapi's event types in Go qapi: golang: Generate qapi's command types in Go qapi: golang: Add CommandResult type to Go qapi: golang: document skip function visit_array_types scripts/qapi/golang.py | 765 +++++++++++++++++++++++++++++++++++++++++ scripts/qapi/main.py | 2 + 2 files changed, 767 insertions(+) create mode 100644 scripts/qapi/golang.py