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Commit beec5311 authored by Administrator's avatar Administrator
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Better config options

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.gitignore
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......@@ -2,3 +2,4 @@ bin/
lib/
share/
local/
config.toml
config.example.toml
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− 0
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......@@ -2,6 +2,7 @@
[[volume]]
volume_group = "exports"
name = "pub"
path = ".snapshots"
[[volume.keep]]
number = 24
......
lvmsnapshot.py
+ 118
− 70
View file @ beec5311
......@@ -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([
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())
......@@ -64,9 +103,17 @@ 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()
......@@ -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):
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",
self.get_mountpoint()
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__":
......
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