uncloud-mravi/ucloud/common/storage_handlers.py

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import shutil
import subprocess as sp
import os
import stat
from abc import ABC
from . import logger
from os.path import join as join_path
from ucloud.settings import settings as config
class ImageStorageHandler(ABC):
handler_name = 'base'
def __init__(self, image_base, vm_base):
self.image_base = image_base
self.vm_base = vm_base
def import_image(self, image_src, image_dest, protect=False):
"""Put an image at the destination
:param src: An Image file
:param dest: A path where :param src: is to be put.
:param protect: If protect is true then the dest is protect (readonly etc)
The obj must exist on filesystem.
"""
raise NotImplementedError()
def make_vm_image(self, image_path, path):
"""Copy image from src to dest
:param src: A path
:param dest: A path
src and destination must be on same storage system i.e both on file system or both on CEPH etc.
"""
raise NotImplementedError()
def resize_vm_image(self, path, size):
"""Resize image located at :param path:
:param path: The file which is to be resized
:param size: Size must be in Megabytes
"""
raise NotImplementedError()
def delete_vm_image(self, path):
raise NotImplementedError()
def execute_command(self, command, report=True, error_origin=None):
if not error_origin:
error_origin = self.handler_name
command = list(map(str, command))
try:
sp.check_output(command, stderr=sp.PIPE)
except sp.CalledProcessError as e:
_stderr = e.stderr.decode('utf-8').strip()
if report:
logger.exception('%s:- %s', error_origin, _stderr)
return False
return True
def vm_path_string(self, path):
raise NotImplementedError()
def qemu_path_string(self, path):
raise NotImplementedError()
def is_vm_image_exists(self, path):
raise NotImplementedError()
class FileSystemBasedImageStorageHandler(ImageStorageHandler):
handler_name = 'Filesystem'
def import_image(self, src, dest, protect=False):
dest = join_path(self.image_base, dest)
try:
shutil.copy(src, dest)
if protect:
os.chmod(dest, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)
except Exception as e:
logger.exception(e)
return False
return True
def make_vm_image(self, src, dest):
src = join_path(self.image_base, src)
dest = join_path(self.vm_base, dest)
try:
shutil.copy(src, dest)
except Exception as e:
logger.exception(e)
return False
return True
def resize_vm_image(self, path, size):
path = join_path(self.vm_base, path)
command = ["qemu-img", "resize", "-f", "raw", path, "{}M".format(size)]
if self.execute_command(command):
return True
else:
self.delete_vm_image(path)
return False
def delete_vm_image(self, path):
path = join_path(self.vm_base, path)
try:
os.remove(path)
except Exception as e:
logger.exception(e)
return False
return True
def vm_path_string(self, path):
return join_path(self.vm_base, path)
def qemu_path_string(self, path):
return self.vm_path_string(path)
def is_vm_image_exists(self, path):
path = join_path(self.vm_base, path)
command = ["ls", path]
return self.execute_command(command, report=False)
class CEPHBasedImageStorageHandler(ImageStorageHandler):
handler_name = 'Ceph'
def import_image(self, src, dest, protect=False):
dest = join_path(self.image_base, dest)
import_command = ["rbd", "import", src, dest]
commands = [import_command]
if protect:
snap_create_command = ["rbd", "snap", "create", "{}@protected".format(dest)]
snap_protect_command = ["rbd", "snap", "protect", "{}@protected".format(dest)]
commands.append(snap_create_command)
commands.append(snap_protect_command)
result = True
for command in commands:
result = result and self.execute_command(command)
return result
def make_vm_image(self, src, dest):
src = join_path(self.image_base, src)
dest = join_path(self.vm_base, dest)
command = ["rbd", "clone", "{}@protected".format(src), dest]
return self.execute_command(command)
def resize_vm_image(self, path, size):
path = join_path(self.vm_base, path)
command = ["rbd", "resize", path, "--size", size]
return self.execute_command(command)
def delete_vm_image(self, path):
path = join_path(self.vm_base, path)
command = ["rbd", "rm", path]
return self.execute_command(command)
def vm_path_string(self, path):
return join_path(self.vm_base, path)
def qemu_path_string(self, path):
return "rbd:{}".format(self.vm_path_string(path))
def is_vm_image_exists(self, path):
path = join_path(self.vm_base, path)
command = ["rbd", "info", path]
return self.execute_command(command, report=False)
def get_storage_handler():
__storage_backend = config['storage']['storage_backend']
if __storage_backend == 'filesystem':
return FileSystemBasedImageStorageHandler(
vm_base=config['storage']['vm_dir'],
image_base=config['storage']['image_dir']
)
elif __storage_backend == 'ceph':
return CEPHBasedImageStorageHandler(
vm_base=config['storage']['ceph_vm_pool'],
image_base=config['storage']['ceph_image_pool']
)
else:
raise Exception('Unknown Image Storage Handler')