diff --git a/.gitignore b/.gitignore
index c4be61019c5532dbfcd3666da29931d50c4a1da6..7206da09056b4ff6434406dd39a8dec6010273e7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ bin/
lib/
share/
local/
+config.toml
diff --git a/config.example.toml b/config.example.toml
index 4d15a1237fb2a449e67d7f31bd83d4f016ee2660..d57f31d94f5f6eb5337f62a57ccab3a26cb27586 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -2,6 +2,7 @@
[[volume]]
volume_group = "exports"
name = "pub"
+ path = ".snapshots"
[[volume.keep]]
number = 24
diff --git a/lvmsnapshot.py b/lvmsnapshot.py
index 74d3dc941ae8a42bd4d2cb73ebb4609cf65a58e5..87765064a0d4de16fe1ae95121c300d8277eccd3 100644
--- a/lvmsnapshot.py
+++ b/lvmsnapshot.py
@@ -31,17 +31,56 @@ import json
from contextlib import contextmanager
from collections import OrderedDict
-SNAPSHOT_BASE_DIR = "/snapshots"
-TIMESTAMP_FORMAT = "%Y-%m-%d-%H-%M"
-PERIOD_KEYS = OrderedDict([
- ("y", 365 * 86400),
- ("m", 31 * 86400),
- ("d", 86400),
- ("H", 3600),
- ("M", 60),
-])
+class Config:
+ snapshot_base_dir = "/snapshots"
+ timestamp_format = "%Y-%m-%d-%H-%M"
+ period_keys = OrderedDict([
+ ("y", 365 * 86400),
+ ("m", 31 * 86400),
+ ("d", 86400),
+ ("H", 3600),
+ ("M", 60),
+ ])
+ min_interval = None
+ volumes = {}
+ periods = {}
+
+ @staticmethod
+ def load():
+ import toml
+ config_path = "config.toml"
+ global_config_path = "/etc/lvm-snapshot.toml"
+ ENV_VAR = "LVM_SNAPSHOT_CONFIG"
+ if not os.path.isfile(config_path) and os.path.isfile(global_config_path):
+ config_path = global_config_path
+ if ENV_VAR in os.environ:
+ config_path = os.environ[ENV_VAR]
+ with open(config_path, "r") as config_file:
+ return toml.load(config_file)
+
+ @staticmethod
+ def parse(config):
+ periods = {}
+ min_interval = None
+ for volume_conf in config["volume"]:
+ name = volume_conf["name"]
+ volume_group = volume_conf["volume_group"]
+ path = volume_conf.get("path")
+ volume = Volume(volume_group, name, path)
+ Config.volumes[volume.get_full_name()] = volume
+ periods[volume] = []
+ for raw_period in volume_conf["keep"]:
+ interval = Period.parse_interval(raw_period["interval"])
+ if min_interval is None or interval < min_interval:
+ min_interval = interval
+ number = int(raw_period["number"])
+ periods[volume].append(
+ Period(target_number=number, interval=interval))
+ Config.min_interval = min_interval
+ Config.periods = periods
def run_process(command, check=True):
+ logging.debug("running command {}".format(command))
result = sp.run(command, check=check, stdout=sp.PIPE, stderr=sp.PIPE)
if result.stdout:
logging.info(result.stdout.decode("utf-8").strip())
@@ -64,12 +103,20 @@ def freeze_xfs(mountpoint, freeze):
run_process(command, check=True)
class Volume:
- def __init__(self, volume_group, name):
+ def __init__(self, volume_group, name, snapshot_dir=None):
self.volume_group = volume_group
self.name = name
+ if snapshot_dir is None:
+ if self.get_full_name() in Config.volumes:
+ snapshot_dir = Config.volumes[self.get_full_name()].snapshot_dir
+ else:
+ snapshot_dir = os.path.join(Config.snapshot_base_dir, name)
+ if not os.path.isabs(snapshot_dir):
+ snapshot_dir = os.path.join(self.get_mountpoint(), snapshot_dir)
+ self.snapshot_dir = snapshot_dir
def __repr__(self):
- return self.get_full_name()
+ return self.get_full_name()
def __eq__(self, other):
return hash(self) == hash(other)
@@ -85,6 +132,7 @@ class Volume:
def get_mountpoint(self):
mapper_device = self.get_mapper_device()
+ logging.debug("searching volume mountpoint for {}".format(mapper_device))
command = [
"/bin/findmnt",
"--source", mapper_device,
@@ -110,7 +158,7 @@ class Snapshot:
return self.get_name()
def get_timestamp_str(self):
- return self.timestamp.strftime(TIMESTAMP_FORMAT)
+ return self.timestamp.strftime(Config.timestamp_format)
def get_name(self):
return "{}-snapshot-{}".format(
@@ -120,7 +168,7 @@ class Snapshot:
@staticmethod
def parse_name(name):
parent_name, _, timestamp_str = name.split("-", 2)
- timestamp = datetime.strptime(timestamp_str, TIMESTAMP_FORMAT)
+ timestamp = datetime.strptime(timestamp_str, Config.timestamp_format)
return parent_name, timestamp
def get_full_volume(self):
@@ -128,12 +176,30 @@ class Snapshot:
def get_mountpoint(self):
return os.path.join(
- SNAPSHOT_BASE_DIR, self.parent_volume.name, self.get_timestamp_str()
+ self.parent_volume.snapshot_dir, self.get_timestamp_str()
)
def create_mountpoint(self):
+ logging.debug("creating mountpoint {}".format(self.get_mountpoint()))
os.makedirs(self.get_mountpoint(), mode=0o755, exist_ok=True)
+ def find_mountpoint(self):
+ logging.debug("searching snapshot mountpoint for {}".format(self.get_name()))
+ command = [
+ "/bin/findmnt",
+ "--source", self.get_mapper_device(),
+ "--json",
+ ]
+ try:
+ result = sp.check_output(command).decode("utf-8")
+ data = json.loads(result)
+ filesystems = data["filesystems"]
+ if len(filesystems) < 1:
+ return None
+ return filesystems[0]["target"]
+ except sp.CalledProcessError:
+ return None
+
def get_mapper_device(self):
return "/dev/mapper/{}-{}".format(
self.parent_volume.volume_group,
@@ -149,6 +215,7 @@ class Snapshot:
self.get_mapper_device())
def create(self):
+ logging.debug("creating snapshot {}".format(self.get_name()))
parent_mountpoint = self.parent_volume.get_mountpoint()
#with xfs_freeze(parent_mountpoint): # not necessary, lvm does this
create_command = [
@@ -162,7 +229,9 @@ class Snapshot:
self.mount()
def mount(self):
+ logging.debug("mounting snapshot {}".format(self.get_name()))
if self.check_mount():
+ logging.debug("already mounted")
return
activate_command = [
"/sbin/lvchange",
@@ -193,6 +262,7 @@ class Snapshot:
return False
def remove(self):
+ logging.debug("removing snapshot {}".format(self.get_name()))
self.unmount()
remove_command = [
"/sbin/lvremove",
@@ -201,12 +271,17 @@ class Snapshot:
run_process(remove_command, check=True)
def unmount(self):
- if self.check_mount():
- unmount_command = [
- "/bin/umount",
- self.get_mountpoint()
- ]
- run_process(unmount_command, check=True)
+ logging.debug("unmounting snapshot {}".format(self.get_name()))
+ mountpoint = self.find_mountpoint()
+ if mountpoint is not None:
+ if self.check_mount():
+ unmount_command = [
+ "/bin/umount",
+ mountpoint
+ ]
+ run_process(unmount_command, check=True)
+ if os.path.isdir(mountpoint):
+ os.rmdir(mountpoint)
deactivate_command = [
"/sbin/lvchange",
"--activate", "n",
@@ -215,7 +290,6 @@ class Snapshot:
]
run_process(deactivate_command, check=True)
self.active = False
- os.rmdir(self.get_mountpoint())
@staticmethod
def list_snapshots():
@@ -272,17 +346,14 @@ class Period:
return datetime.now() - self.target_number * self.interval
@staticmethod
- def build_regex(period_keys=None):
- if period_keys is None:
- period_keys = PERIOD_KEYS
- parts = [r"(?:(?P<{0}>\d+){0})?".format(key) for key in period_keys]
+ def build_regex():
+ parts = [r"(?:(?P<{0}>\d+){0})?".format(key) for key in Config.period_keys]
return "".join(parts)
@staticmethod
- def parse_interval(text, period_keys=None):
- if period_keys is None:
- period_keys = PERIOD_KEYS
- regex = Period.build_regex(period_keys)
+ def parse_interval(text):
+ period_keys = Config.period_keys
+ regex = Period.build_regex()
match = re.fullmatch(regex, text)
if match is None:
raise Exception("Invalid interval config: '{}', "
@@ -294,36 +365,6 @@ class Period:
seconds += period_keys[key] * int(groups[key])
return timedelta(seconds=seconds)
-def load_config():
- import sys
- import toml
- config_path = "config.toml"
- global_config_path = "/etc/lvm-snapshot.toml"
- ENV_VAR = "LVM_SNAPSHOT_CONFIG"
- if not os.path.isfile(config_path) and os.path.isfile(global_config_path):
- config_path = global_config_path
- if ENV_VAR in os.environ:
- config_path = os.environ[ENV_VAR]
- with open(config_path, "r") as config_file:
- return toml.load(config_file)
-
-def parse_config(config):
- periods = {}
- min_interval = None
- for volume_conf in config["volume"]:
- name = volume_conf["name"]
- volume_group = volume_conf["volume_group"]
- volume = Volume(volume_group, name)
- periods[volume] = []
- for raw_period in volume_conf["keep"]:
- interval = Period.parse_interval(raw_period["interval"])
- if min_interval is None or interval < min_interval:
- min_interval = interval
- number = int(raw_period["number"])
- periods[volume].append(
- Period(target_number=number, interval=interval))
- return periods, min_interval
-
def mark_snapshots(snapshots, periods, min_interval):
all_snapshots = set(snapshots)
marked_snapshots = set()
@@ -342,29 +383,28 @@ def mark_snapshots(snapshots, periods, min_interval):
unmarked_snapshots = all_snapshots - marked_snapshots
return unmarked_snapshots
-def list_snapshots(**kwargs):
+def list_snapshots():
snapshots = Snapshot.list_snapshots()
for volume in snapshots:
print("volume: {}".format(str(volume)))
for snapshot in snapshots[volume]:
print(" {}".format(str(snapshot)))
-def mount_snapshots(**kwargs):
+def mount_snapshots():
snapshots = Snapshot.list_snapshots()
for volume in snapshots:
for snapshot in snapshots[volume]:
snapshot.mount()
-def unmount_snapshots(**kwargs):
+def unmount_snapshots():
snapshots = Snapshot.list_snapshots()
for volume in snapshots:
for snapshot in snapshots[volume]:
snapshot.unmount()
def update_snapshots():
- config = load_config()
snapshots = Snapshot.list_snapshots()
- periods, min_interval = parse_config(config)
+ periods, min_interval = Config.periods, Config.min_interval
for volume in set(periods.keys()) - set(snapshots.keys()):
logging.warn("Warning: Volume {} is configured but does not exist or has no snapshots.".format(volume))
for volume in set(snapshots.keys()) - set(periods.keys()):
@@ -372,8 +412,10 @@ def update_snapshots():
snapshots.pop(volume)
for volume in snapshots:
unmarked_snapshots = mark_snapshots(snapshots[volume], periods[volume], min_interval)
+ logging.info("removing snapshots {}".format(unmarked_snapshots))
for snapshot in unmarked_snapshots:
snapshot.remove()
+ logging.info("creating new snapshot")
new_snapshot = Snapshot(volume, datetime.now())
new_snapshot.create()
@@ -386,14 +428,20 @@ operations = {
def main():
import argparse
- parser = argparse.ArgumentParser()
- parser.add_argument("command", help="list|update|mount|unmount")
- parser.add_argument("--verbose", action="store_true", help="do not redirect the command output to /dev/null")
+ parser = argparse.ArgumentParser(description="Manage snapshots of thin LVM volumes")
+ parser.add_argument("command", choices=["list", "update", "mount", "unmount"], default="list")
+ parser.add_argument("--verbose", "-v", action="count", help="do not redirect the command output to /dev/null")
args = parser.parse_args()
- loglevel = logging.ERROR
- if args.verbose:
- loglevel = logging.INFO
+ loglevels = {
+ 0: logging.ERROR,
+ 1: logging.WARNING,
+ 2: logging.INFO,
+ 3: logging.DEBUG
+ }
+ loglevel = loglevels[min(3, max(0, args.verbose))]
logging.basicConfig(level=loglevel)
+ Config.parse(Config.load())
+
operations[args.command]()
if __name__ == "__main__":