def test_fstab_get_uuid(self):
fstab = Fstab(fstab=os.path.join(self.testdir, "data", "fstab"))
self.assertEqual(fstab.uuid_for_mountpoint("/"), "UUID=fe63f598-1906-478e-acc7-f74740e78d1f")
class AptBtrfsSnapshot(object):
""" the high level object that interacts with the snapshot system """
def __init__(self, fstab="/etc/fstab", sandbox=None):
self.fstab = Fstab(fstab)
self.commands = LowLevelCommands()
# if we haven't been given a testing ground to play in, mount the real
# root volume
self.test = sandbox is not None
self.mp = sandbox
if self.mp is None:
uuid = self.fstab.uuid_for_mountpoint("/")
mountpoint = tempfile.mkdtemp(prefix="apt-btrfs-snapshot-mp-")
if not self.commands.mount(uuid, mountpoint):
os.rmdir(mountpoint)
raise Exception("Unable to mount root volume")
self.mp = mountpoint
snapshots.setup(self.mp)
def __del__(self):
""" unmount root volume if necessary """
# This will probably not get run if there are cyclic references.
# check thoroughly because we get called even if __init__ fails
if not self.test and self.mp is not None:
res = self.commands.umount(self.mp)
os.rmdir(self.mp)
self.mp = None
def _get_now_str(self):
return datetime.datetime.now().replace(microsecond=0).isoformat(
str('_'))
def _parse_older_than_to_datetime(self, timefmt):
if isinstance(timefmt, datetime.datetime):
return timefmt
now = datetime.datetime.now()
if not timefmt.endswith("d"):
raise Exception("Please specify time in days (e.g. 10d)")
days = int(timefmt[:-1])
return now - datetime.timedelta(days)
def _get_last_snapshot_time(self):
last_snapshot = datetime.datetime.fromtimestamp(0.0)
if self.test:
last_snapshot_file = '/tmp/apt_last_snapshot'
else:
last_snapshot_file = '/run/apt_last_snapshot'
if os.path.exists(last_snapshot_file):
try:
t = open(last_snapshot_file)
last_snapshot = \
datetime.datetime.fromtimestamp(float(t.readline()))
except:
# If we fail to read the timestamp for some reason, just return
# the default value silently
pass
finally:
t.close()
return last_snapshot
def _save_last_snapshot_time(self):
if self.test:
last_snapshot_file = '/tmp/apt_last_snapshot'
else:
last_snapshot_file = '/run/apt_last_snapshot'
f = open(last_snapshot_file, 'w')
f.write(str(time.time()))
f.close()
def _get_status(self):
parent = Snapshot("@").parent
if parent is not None:
date_parent = parent.date
else:
date_parent = None
if self.test:
testdir = os.path.dirname(os.path.abspath(__file__))
if not testdir.endswith("test"):
testdir = os.path.join(testdir, "test")
var_location = os.path.join(testdir, "data/var")
history = DpkgHistory(since = date_parent,
var_location = var_location)
else:
history = DpkgHistory(since = date_parent)
return parent, history
def _prettify_changes(self, history, i_indent="- ", s_indent=" "):
if history == None or history == NO_HISTORY:
return [i_indent + "No packages operations recorded"]
output = []
for op in ("install", "auto-install", "upgrade", "remove", "purge"):
if len(history[op]) > 0:
output.append("%s%ss (%d):" % (i_indent, op, len(history[op])))
packages = []
for p, v in history[op]:
packages.append(p)
packages = ", ".join(packages)
if sys.stdout.isatty():
# if we are in a terminal, wrap text to match its width
rows, columns = os.popen('stty size', 'r').read().split()
packages = textwrap.wrap(packages, width=int(columns),
initial_indent=s_indent, subsequent_indent=s_indent,
break_on_hyphens=False)
output.extend(packages)
return output
def status(self):
""" show current root's parent and recent changes """
return self.show("@")
def show(self, snapshot, compact=False):
""" show details pertaining to given snapshot """
snapshot = Snapshot(snapshot)
if snapshot.name == "@":
parent, changes = self._get_status()
else:
parent, changes = snapshot.parent, snapshot.changes
fca = snapshots.first_common_ancestor("@", snapshot)
mainline = (fca == snapshot) and 'Is' or "Isn't"
mainline = "%s an ancestor of @" % mainline
pretty_history = self._prettify_changes(changes)
if parent == None:
parent = "unknown"
else:
parent = parent.name
if not compact:
title = "Snapshot %s" % snapshot.name
print(title)
if snapshot.name != "@":
print(mainline)
print("Parent: %s" % parent)
if parent == "unknown" and snapshot.name == "@":
print("dpkg history shown for the last 30 days")
print("dpkg history:")
else:
print("dpkg history for %s" % snapshot.name)
print("\n".join(pretty_history))
return True
def create(self, tag=""):
""" create a new apt-snapshot of @, tagging it if a tag is given """
if 'APT_NO_SNAPSHOTS' in os.environ and tag == "":
print("Shell variable APT_NO_SNAPSHOTS found, skipping creation")
return True
elif 'APT_NO_SNAPSHOTS' in os.environ and tag != "":
print("Shell variable APT_NO_SNAPSHOTS found, but tag supplied, "
"creating snapshot")
last = self._get_last_snapshot_time()
# If there is a recent snapshot and no tag supplied, skip creation
if tag == "" \
and last > datetime.datetime.now() - datetime.timedelta(seconds=60):
print("A recent snapshot already exists: %s" % last)
return True
# make snapshot
snap_id = SNAP_PREFIX + self._get_now_str() + tag
res = self.commands.btrfs_subvolume_snapshot(
os.path.join(self.mp, "@"),
os.path.join(self.mp, snap_id))
# set root's new parent
Snapshot("@").parent = snap_id
# find and store dpkg changes
parent, history = self._get_status()
Snapshot(snap_id).changes = history
self._save_last_snapshot_time()
return res
def tag(self, snapshot, tag):
""" Adds/replaces the tag for the given snapshot """
children = Snapshot(snapshot).children
pos = len(SNAP_PREFIX)
new_name = snapshot[:pos + 19] + tag
old_snap = os.path.join(self.mp, snapshot)
new_snap = os.path.join(self.mp, new_name)
os.rename(old_snap, new_snap)
tagged = Snapshot(new_name)
for child in children:
child.parent = tagged
return True
def list(self):
# The function name will not clash with reserved keywords. It is only
# accessible via self.list()
print("Available snapshots:")
print(" \n".join(snapshots.get_list()))
return True
def list_older_than(self, timefmt):
older_than = self._parse_older_than_to_datetime(timefmt)
print("Available snapshots older than '%s':" % timefmt)
print(" \n".join(snapshots.get_list(older_than=older_than)))
return True
def _prompt_for_tag(self):
print("You haven't specified a tag for the snapshot that will be created from the current state.")
tag = raw_input("Please enter a tag: ")
if tag:
tag = "-" + tag
return tag
def set_default(self, snapshot, tag=""):
""" backup @ and replace @ with a copy of given snapshot """
if not tag:
tag = self._prompt_for_tag()
snapshot = Snapshot(snapshot)
new_root = os.path.join(self.mp, snapshot.name)
if (
os.path.isdir(new_root) and
snapshot.name.startswith(SNAP_PREFIX)):
default_root = os.path.join(self.mp, "@")
staging = os.path.join(self.mp, "@apt-btrfs-staging")
if os.path.lexists(staging):
raise Exception("Reserved directory @apt-btrfs-staging "
"exists\nPlease remove from btrfs volume root before "
"trying again")
# find and store dpkg changes
date, history = self._get_status()
Snapshot("@").changes = history
# snapshot the requested default so as not to remove it
res = self.commands.btrfs_subvolume_snapshot(new_root, staging)
if not res:
raise Exception("Could not create snapshot")
# make backup name
backup = os.path.join(self.mp,
SNAP_PREFIX + self._get_now_str()) + tag
# if backup name is already in use, wait a sec and try again
if os.path.exists(backup):
time.sleep(1)
backup = os.path.join(self.mp,
SNAP_PREFIX + self._get_now_str())
# move everything into place
os.rename(default_root, backup)
os.rename(staging, default_root)
# remove @/etc/apt-btrfs-changes & set root's new parent
new_default = Snapshot("@")
new_default.changes = None
new_default.parent = snapshot.name
print("Default changed to %s, please reboot for changes to take "
"effect." % snapshot.name)
else:
print("You have selected an invalid snapshot. Please make sure "
"that it exists, and that its name starts with "
"\"%s\"" % SNAP_PREFIX)
return True
def rollback(self, number=1, tag=""):
back_to = Snapshot("@")
for i in range(number):
back_to = back_to.parent
if back_to == None:
raise Exception("Can't rollback that far")
return False
return self.set_default(back_to, tag)
def delete(self, snapshot):
snapshot = Snapshot(snapshot)
to_delete = os.path.join(self.mp, snapshot.name)
res = True
if (
os.path.isdir(to_delete) and
snapshot.name.startswith(SNAP_PREFIX)):
# correct parent links and combine change info
parent = snapshot.parent
children = snapshot.children
old_history = snapshot.changes
# clean-ups in the global vars of
snapshots.list_of.remove(snapshot)
if parent != None and parent.name in snapshots.children:
snapshots.children[parent.name].remove(snapshot)
for child in children:
child.parent = parent
# and do the same again in the global vars of snapshots
# messy but necessary for delete_older_than to work
snapshots.parents[child.name] = parent
if parent != None:
snapshots.children[parent.name].append(child) # necessary
newer_history = child.changes
if old_history == None:
combined = newer_history
elif newer_history == None:
combined = None
else:
combined = old_history + newer_history
child.changes = combined
res = self.commands.btrfs_delete_snapshot(to_delete)
else:
print("You have selected an invalid snapshot. Please make sure "
"that it exists, and that its name starts with "
"\"%s\"" % SNAP_PREFIX)
return res
def delete_older_than(self, timefmt):
older_than = self._parse_older_than_to_datetime(timefmt)
res = True
list_of = snapshots.get_list(older_than=older_than)
list_of.sort(key = lambda x: x.date, reverse = True)
for snap in list_of:
if len(snap.children) < 2 and snap.tag == "":
res &= self.delete(snap)
return res
def prune(self, snapshot):
snapshot = Snapshot(snapshot)
res = True
if len(snapshot.children) != 0:
raise Exception("Snapshot is not the end of a branch")
while True:
parent = snapshot.parent
res &= self.delete(snapshot)
snapshot = parent
if snapshot == None or len(snapshot.children) != 0:
break
return res
def tree(self):
date_parent, history = self._get_status()
tree = TreeView(history)
tree.print()
def recent(self, number, snapshot):
print("%s and its predecessors. Showing %d snapshots.\n" % (snapshot,
number))
snapshot = Snapshot(snapshot)
for i in range(number):
self.show(snapshot, compact=True)
snapshot = snapshot.parent
if snapshot == None or i == number - 1:
break
else:
print()
return True
def clean(self, what="apt-cache"):
snapshot_list = snapshots.get_list()
for snapshot in snapshot_list:
path = os.path.join(self.mp, snapshot.name)
if what == "apt-cache":
path = os.path.join(path, "var/cache/apt/archives")
if not os.path.exists(path):
continue
dirlist = os.listdir(path)
for f in dirlist:
fpath = os.path.join(path, f)
if f.endswith(".deb") and os.path.lexists(fpath):
os.remove(fpath)
