#!/usr/bin/env python3 # group: quick # # Tests converting qcow2 compressed to NBD # # Copyright (c) 2020 Nir Soffer <nirsof@gmail.com> # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. # # owner=nirsof@gmail.com import io import tarfile import iotests from iotests import ( file_path, qemu_img, qemu_img_check, qemu_img_create, qemu_img_log, qemu_img_measure, qemu_io, qemu_nbd_popen, img_info_log, ) iotests.script_initialize(supported_fmts=["qcow2"]) # Create source disk. Using qcow2 to enable strict comparing later, and # avoid issues with random filesystem on CI environment. src_disk = file_path("disk.qcow2") qemu_img_create("-f", iotests.imgfmt, src_disk, "1g") qemu_io("-f", iotests.imgfmt, "-c", "write 1m 64k", src_disk) # The use case is writing qcow2 image directly into an ova file, which # is a tar file with specific layout. This is tricky since we don't know the # size of the image before compressing, so we have to do: # 1. Add an ovf file. # 2. Find the offset of the next member data. # 3. Make room for image data, allocating for the worst case. # 4. Write compressed image data into the tar. # 5. Add a tar entry with the actual image size. # 6. Shrink the tar to the actual size, aligned to 512 bytes. tar_file = file_path("test.ova") with tarfile.open(tar_file, "w") as tar: # 1. Add an ovf file. ovf_data = b"<xml/>" ovf = tarfile.TarInfo("vm.ovf") ovf.size = len(ovf_data) tar.addfile(ovf, io.BytesIO(ovf_data)) # 2. Find the offset of the next member data. offset = tar.fileobj.tell() + 512 # 3. Make room for image data, allocating for the worst case. measure = qemu_img_measure("-O", "qcow2", src_disk) tar.fileobj.truncate(offset + measure["required"]) # 4. Write compressed image data into the tar. nbd_sock = file_path("nbd-sock", base_dir=iotests.sock_dir) nbd_uri = "nbd+unix:///exp?socket=" + nbd_sock # Use raw format to allow creating qcow2 directly into tar file. with qemu_nbd_popen( "--socket", nbd_sock, "--export-name", "exp", "--format", "raw", "--offset", str(offset), tar_file): iotests.log("=== Target image info ===") # Not img_info_log as it enforces imgfmt, but now we print info on raw qemu_img_log("info", nbd_uri) qemu_img( "convert", "-f", iotests.imgfmt, "-O", "qcow2", "-c", src_disk, nbd_uri) iotests.log("=== Converted image info ===") img_info_log(nbd_uri) iotests.log("=== Converted image check ===") qemu_img_log("check", nbd_uri) iotests.log("=== Comparing to source disk ===") qemu_img_log("compare", src_disk, nbd_uri) actual_size = qemu_img_check(nbd_uri)["image-end-offset"] # 5. Add a tar entry with the actual image size. disk = tarfile.TarInfo("disk") disk.size = actual_size tar.addfile(disk) # 6. Shrink the tar to the actual size, aligned to 512 bytes. tar_size = offset + (disk.size + 511) & ~511 tar.fileobj.seek(tar_size) tar.fileobj.truncate(tar_size) with tarfile.open(tar_file) as tar: members = [{"name": m.name, "size": m.size, "offset": m.offset_data} for m in tar] iotests.log("=== OVA file contents ===") iotests.log(members)