From patchwork Fri May 18 23:33:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tremer X-Patchwork-Id: 1773 Return-Path: Received: from mail01.ipfire.org (unknown [172.28.1.200]) by web02.i.ipfire.org (Postfix) with ESMTP id 3F4E760A29 for ; Fri, 18 May 2018 15:34:26 +0200 (CEST) Received: from mail01.i.ipfire.org (localhost [IPv6:::1]) by mail01.ipfire.org (Postfix) with ESMTP id 02D27111E122; Fri, 18 May 2018 14:34:25 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ipfire.org; s=201801; t=1526650466; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references:list-id:list-unsubscribe:list-subscribe:list-post; bh=hX/UG7Aw7lkk2NY3kV3ytz89VUq/xavwPYOlzgzpkts=; b=Gh4T+vccWFxHKAz0pAujNyj/E36tvJxAkZKdhPu79XszfDQQb6D0CnqSFcykShF7Spt1br GUp5/U8NH13eg4xZGVaUFxmAeyaK0Maum+pLAQrUAMg3PuyCqtN1r6ZxIbqY3zDGi57U/X 8gGFZZyOh/Vu+s0ubdQUHwc0xnaJ1Zh6FFmRjyllVqAecw5nRrpH5KFvlswJDBymtAI4OZ ZzjEezsaSBc5MYiU8WcZA1WwCIYNtRZ0WuMh7IaGDJlndSojR3E4RgANn80QjqaZzMUn4h l6PdPstq7K20INPYIwFQnU5gwkVScEivNbFCO9NyYzGvR0vOB3PgZr1orG3HPQ== Authentication-Results: mail01.i.ipfire.org; auth=pass smtp.auth=ms smtp.mailfrom=michael.tremer@ipfire.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ipfire.org; s=201801; t=1526650449; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=hX/UG7Aw7lkk2NY3kV3ytz89VUq/xavwPYOlzgzpkts=; b=hKl8t7HLFgHQpD9q/eg5vzDhNvfaPAMN7culvC9diCizF3x5UUNnoY9iW46g95TTjXOhJp +ZGUqlDVSae7JM8OHYoSE2Pg/A+y39eL7dEqW8ZW6RfxbmcbAH21PRik25en3pto3joH7U 5kXOD9m9PQq5h6M+tYgM6V7e7JW2dmZGJnhri5BcLNglqqmdTYEAApnEU0vw3VAfaOKOcY iZ/y0d41a3LKAb58gg78SJXRkxbCYxghH8U299BIgXliu+vOB018pn+6bce3Cbrzq3oeEV skjuD5lWFj6uzxs2NGszVUt29qv7uRwXY9Q0WUKSv0cqXTAyj7Nr1wJvCuaVhQ== Received: from rice-oxley.tremer.co.uk (unknown [88.98.219.132]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mail01.ipfire.org (Postfix) with ESMTPSA id E616910D22DC; Fri, 18 May 2018 14:34:08 +0100 (BST) From: Michael Tremer To: development@lists.ipfire.org Subject: [PATCH 5/7] Refactoring of Disk class Date: Fri, 18 May 2018 14:33:57 +0100 Message-Id: <20180518133359.2481778-5-michael.tremer@ipfire.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180518133359.2481778-1-michael.tremer@ipfire.org> References: <20180518133359.2481778-1-michael.tremer@ipfire.org> X-Spamd-Result: default: False [-7.06 / 11.00]; ASN(0.00)[asn:56478, ipnet:88.98.216.0/22, country:GB]; DKIM_SIGNED(0.00)[]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; ARC_NA(0.00)[]; BAYES_HAM(-3.00)[100.00%]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MID_CONTAINS_FROM(1.00)[]; RCVD_COUNT_ZERO(0.00)[0]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM(-2.96)[-0.985,0]; REPLY(-2.00)[] X-Spam-Status: No, score=-7.06 X-Rspamd-Server: mail01.i.ipfire.org Cc: Michael Tremer X-BeenThere: development@lists.ipfire.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: IPFire development talk List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: development-bounces@lists.ipfire.org Sender: "Development" This is an example of how the code could take advantage of Python contexts. The with statement will open the context and when it is left (either normally or because of an exception), the __exit__() method is called and can be used to cleanup. Cleaning up is in this case umounting the image file, but could also be used to shutdown and destroy a virtual machine or network. Signed-off-by: Michael Tremer Signed-off-by: Michael Tremer <michael.tremer@ipfire.org> --- src/nitsi/disk.py | 92 +++++++++++++++++++++++++++++--------------- src/nitsi/machine.py | 13 ++----- 2 files changed, 65 insertions(+), 40 deletions(-) diff --git a/src/nitsi/disk.py b/src/nitsi/disk.py index 29782574282e..5f465956c849 100755 --- a/src/nitsi/disk.py +++ b/src/nitsi/disk.py @@ -8,43 +8,75 @@ import tempfile logger = logging.getLogger("nitsi.disk") +class Disk(object): + def __init__(self, path, part_uuid): + self.path = path + self.part_uuid = part_uuid -class disk(): - def __init__(self, disk): - self.log = logger.getChild(os.path.basename(disk)) - self.log.debug("Initiated a disk class for {}".format(disk)) + self.log = logger.getChild(os.path.basename(self.path)) + self.log.debug("Initiated a disk class for {}".format(self.path)) + + # Create GuestFS object for this disk self.con = guestfs.GuestFS(python_return_dict=True) - self.con.add_drive_opts(disk, format="qcow2") + self.con.add_drive_opts(self.path, format="qcow2") - def mount(self, uuid, path): - self.log.debug("Trying to mount the partion with uuid: {} under {}".format(uuid, path)) + def __enter__(self): + # Launch the GuestFS backend self.con.launch() - part = self.con.findfs_uuid(uuid) - self.con.mount(part, path) - def copy_in(self, fr, to): - self.log.debug("Going to copy some files into the image.") - tmp = tempfile.mkstemp() - tmp = tmp[1] + ".tar" - with tarfile.open(tmp, "w") as tar: - for file in fr: - self.log.debug("Adding {} to be copied into the image".format(file)) - tar.add(file, arcname=os.path.basename(file)) + # Find partition to mount + part = self.con.findfs_uuid(self.part_uuid) + if not part: + raise RuntimeError("Could not find partition %s" % self.part_uuid) - self.log.debug("Going to copy the files into the image") - self.con.tar_in_opts(tmp, to) + # Mounting partition + self._mount(part) - def umount(self, path): - self.log.debug("Unmounting the image") - self.con.umount_opts(path) + return MountedDisk(self, part) - def close(self): - self.log.debug("Flush the image and closing the connection") + def __exit__(self, type, value, traceback): + # Umount the disk image + self._umount() + + # Shuts down the GuestFS backend self.con.shutdown() - self.con.close() -# test = disk("/var/lib/libvirt/images/alice.qcow2") -# test.mount("45598e92-3487-4a1b-961d-79aa3dd42a7d", "/") -# test.copy_in("/home/jonatan/nitsi/libguestfs-test", "/root/") -# test.umount("/") -# test.close() + def _mount(self, part, path="/"): + """ + Mounts the selected partition to path + """ + self.log.debug("Mounting partition %s to %s" % (part, path)) + + self.con.mount(part, path) + + def _umount(self, path="/"): + self.log.debug("Umounting %s" % path) + + self.con.umount_opts(path) + + +class MountedDisk(object): + """ + Provides commands that can only be executed when the disk is mounted. + + Leaving the context will automatically umount the disk. + """ + def __init__(self, disk, part): + self.disk = disk + self.part = part + + def copy_in(self, files, destination): + self.disk.log.debug("Going to copy some files into the image") + + with tempfile.NamedTemporaryFile("wb", suffix=".tar") as f: + with tarfile.open(fileobj=f, mode="w") as t: + for file in files: + self.disk.log.debug("Adding %s" % file) + t.add(file, arcname=os.path.basename(file)) + + self.disk.log.debug("Going to copy the files into the image") + self.disk.con.tar_in_opts(f.name, destination) + + +# with disk("/var/lib/libvirt/images/alice.qcow2", "45598e92-3487-4a1b-961d-79aa3dd42a7d") as test: +# test.copy_in("/home/jonatan/nitsi/libguestfs-test", "/root/") diff --git a/src/nitsi/machine.py b/src/nitsi/machine.py index 0b4617aed8dc..9efa4dde5688 100644 --- a/src/nitsi/machine.py +++ b/src/nitsi/machine.py @@ -40,8 +40,7 @@ class machine(): if not os.path.isfile(self.image): self.log.error("No such file: {}".format(self.image)) - self.root_uid = root_uid - self.disk = disk.disk(image) + self.disk = disk.Disk(image, root_uid) self.username = username self.password = password @@ -132,11 +131,5 @@ class machine(): return self.serial_con.command(cmd) def copy_in(self, fr, to): - try: - self.disk.mount(self.root_uid, "/") - self.disk.copy_in(fr, to) - except BaseException as e: - self.log.error(e) - finally: - self.disk.umount("/") - self.disk.close() + with self.disk as d: + d.copy_in(fr, to)