Re: [Qemu-devel] [PATCH] tests/vm: Use subprocess.Popen() with to uncompress XZ files

[Fam Zheng <famz@redhat.com>]

On Sat, 10/13 02:30, Philippe Mathieu-Daudé wrote:
> Avoiding the file copy greatly speeds the process up.
> 
> Comparison with network file already cached, stopping after build_image():
> 
> Before:
>   $ time make vm-build-freebsd
>   real    1m38.153s
>   user    1m16.871s
>   sys     0m19.325s
> 
> After:
>   $ time make vm-build-freebsd
>   real    0m13.512s
>   user    0m9.520s
>   sys     0m3.685s
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  tests/vm/centos  | 5 ++---
>  tests/vm/freebsd | 9 ++-------
>  tests/vm/netbsd  | 9 ++-------
>  tests/vm/openbsd | 9 ++-------
>  4 files changed, 8 insertions(+), 24 deletions(-)
> 
> diff --git a/tests/vm/centos b/tests/vm/centos
> index afd560c564..fa653c1650 100755
> --- a/tests/vm/centos
> +++ b/tests/vm/centos
> @@ -63,9 +63,8 @@ class CentosVM(basevm.BaseVM):
>  
>      def build_image(self, img):
>          cimg = self._download_with_cache("https://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud-1802.qcow2.xz")
> -        img_tmp = img + ".tmp"
> -        subprocess.check_call(["cp", "-f", cimg, img_tmp + ".xz"])
> -        subprocess.check_call(["xz", "-df", img_tmp + ".xz"])
> +        with open(img, 'wb', 0644) as output:
> +            subprocess.Popen(["xz", "--threads=0", "--decompress", "--force", "--to-stdout", cimg], stdout=output)
>          subprocess.check_call(["qemu-img", "resize", img_tmp, "50G"])
>          self.boot(img_tmp, extra_args = ["-cdrom", self._gen_cloud_init_iso()])
>          self.wait_ssh()
> diff --git a/tests/vm/freebsd b/tests/vm/freebsd
> index b6983127d0..7ec43a4c5c 100755
> --- a/tests/vm/freebsd
> +++ b/tests/vm/freebsd
> @@ -31,13 +31,8 @@ class FreeBSDVM(basevm.BaseVM):
>      def build_image(self, img):
>          cimg = self._download_with_cache("http://download.patchew.org/freebsd-11.1-amd64.img.xz",
>                  sha256sum='adcb771549b37bc63826c501f05121a206ed3d9f55f49145908f7e1432d65891')
> -        img_tmp_xz = img + ".tmp.xz"
> -        img_tmp = img + ".tmp"
> -        subprocess.check_call(["cp", "-f", cimg, img_tmp_xz])
> -        subprocess.check_call(["xz", "-df", img_tmp_xz])
> -        if os.path.exists(img):
> -            os.remove(img)
> -        os.rename(img_tmp, img)
> +        with open(img, 'wb', 0644) as output:
> +            subprocess.Popen(["xz", "--threads=0", "--decompress", "--force", "--to-stdout", cimg], stdout=output)

What if xz is terminated before the image is fully polulated? The next time make
is invoked we want build_image to start over, but with this change it won't.

Fam

>  
>  if __name__ == "__main__":
>      sys.exit(basevm.main(FreeBSDVM))
> diff --git a/tests/vm/netbsd b/tests/vm/netbsd
> index a4e25820d5..99023344b7 100755
> --- a/tests/vm/netbsd
> +++ b/tests/vm/netbsd
> @@ -31,13 +31,8 @@ class NetBSDVM(basevm.BaseVM):
>      def build_image(self, img):
>          cimg = self._download_with_cache("http://download.patchew.org/netbsd-7.1-amd64.img.xz",
>                                           sha256sum='b633d565b0eac3d02015cd0c81440bd8a7a8df8512615ac1ee05d318be015732')
> -        img_tmp_xz = img + ".tmp.xz"
> -        img_tmp = img + ".tmp"
> -        subprocess.check_call(["cp", "-f", cimg, img_tmp_xz])
> -        subprocess.check_call(["xz", "-df", img_tmp_xz])
> -        if os.path.exists(img):
> -            os.remove(img)
> -        os.rename(img_tmp, img)
> +        with open(img, 'wb', 0644) as output:
> +            subprocess.Popen(["xz", "--threads=0", "--decompress", "--force", "--to-stdout", cimg], stdout=output)
>  
>  if __name__ == "__main__":
>      sys.exit(basevm.main(NetBSDVM))
> diff --git a/tests/vm/openbsd b/tests/vm/openbsd
> index 52500ee52b..57604bb43d 100755
> --- a/tests/vm/openbsd
> +++ b/tests/vm/openbsd
> @@ -32,13 +32,8 @@ class OpenBSDVM(basevm.BaseVM):
>      def build_image(self, img):
>          cimg = self._download_with_cache("http://download.patchew.org/openbsd-6.1-amd64.img.xz",
>                  sha256sum='8c6cedc483e602cfee5e04f0406c64eb99138495e8ca580bc0293bcf0640c1bf')
> -        img_tmp_xz = img + ".tmp.xz"
> -        img_tmp = img + ".tmp"
> -        subprocess.check_call(["cp", "-f", cimg, img_tmp_xz])
> -        subprocess.check_call(["xz", "-df", img_tmp_xz])
> -        if os.path.exists(img):
> -            os.remove(img)
> -        os.rename(img_tmp, img)
> +        with open(img, 'wb', 0644) as output:
> +            subprocess.Popen(["xz", "--threads=0", "--decompress", "--force", "--to-stdout", cimg], stdout=output)
>  
>  if __name__ == "__main__":
>      sys.exit(basevm.main(OpenBSDVM))
> -- 
> 2.19.1
>