Re: [PATCH 5/7] Refactoring of Disk class

Hi,

I had merged all other patches and will have a closer look at this one later

Jonatan

Am Fr, 18. Mai, 2018 um 3:33 schrieb Michael Tremer michael.tremer@ipfire.org:

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 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)
  

-- 2.17.0