* fixed weeding

* added weed_enable option and default it to unset to prevent removing snapshots of unmanaged file systems
* added locking when sending and weeding snapshots
* fixed syslog logging format

bin/zsnapper

@@ -28,6 +28,7 @@ RET_CODES = {
 DEFAULT_CONFIG = {
         'snapshot_interval': None,
         'custom_keep_interval': None,
+        'weed_enable': False,
         'keep_yearly': 0,
         'keep_monthly': 0,
         'keep_weekly': 0,
@@ -87,29 +88,12 @@ def get_config_for_fs(fs, config):
 
     return fs_config
 
-def main():
+
-    config = configparser.SafeConfigParser()
+def do_snapshots(fslist, snapshots, config, sudo):
-    config.read('/etc/zsnapper.ini')
+    failed_snapshots = set()
-    sudo = False
+    now = datetime.datetime.now()
-    ret = RET_CODES['SUCCESS']
     log = logging.getLogger(LOGGER)
 
-    if os.getuid() != 0:
-        sudo = True
-        try:
-            sudo = config.get('settings', 'sudo')
-        except (configparser.NoOptionError, configparser.NoSectionError):
-            pass
-    
-    fslist = sorted(zsnaplib.get_filesystems(sudo))
-    snapshots = zsnaplib.get_snapshots(sudo)
-    now = datetime.datetime.now()
-    
-    # if we fail to create or send a snapshot we do not want to remove 
-    # the existing snapshots...
-    failed_snapshots = set()
-
-    # First iteration: create snapshots
     for fs in fslist:
         conf = get_config_for_fs(fs, config)
         if not conf['snapshot_interval']:
@@ -126,15 +110,14 @@ def main():
                 log.info('{} snapshot created'.format(fs))
             except zsnaplib.ZFSSnapshotError as e:
                 log.warning(e)
-                ret = RET_CODES['ERROR']
                 failed_snapshots.add(fs)
-        
+    return failed_snapshots
-    # reload all snapshots so we get our new snapshots here
-    snapshots = zsnaplib.get_snapshots(sudo)
 
-    # Second iteration: Send snapshots
+def send_snapshots(fslist, snapshots, config, sudo):
+    failed_snapshots = set()
     remote_hosts = {}
     remote_targets = {}
+    log = logging.getLogger(LOGGER)
     for fs in fslist:
         conf = get_config_for_fs(fs, config)
         remote_snapshots = None
@@ -194,7 +177,6 @@ def main():
             except zsnaplib.ZFSSnapshotError as e:
                 failed_snapshots.add(fs)
                 log.warning(e)
-                ret = RET_CODES['ERROR']
                 continue
             remote_snapshots[remote_fs] = [base_snap]
 
@@ -206,8 +188,7 @@ def main():
                 break
         if not last_remote:
             failed_snapshots.add(fs)
-            log.warning('No common snapshot local and remote, you need to create a new base copy!')
+            log.warning('{}: No common snapshot local and remote, you need to create a new base copy!'.format(fs))
-            ret = RET_CODES['ERROR']
             continue
         last_local = snapshots[fs][0]
         if last_remote == last_local:
@@ -229,8 +210,10 @@ def main():
             log.info('{} successfully sent to remote'.format(fs))
         except zsnaplib.ZFSSnapshotError as e:
             log.warning(e)
+    return failed_snapshots
 
-    # Third iteration: weed old snapshots
+def weed_snapshots(fslist, snapshots, config, sudo, failed_snapshots):
+    log = logging.getLogger(LOGGER)
     for fs in fslist:
         conf = get_config_for_fs(fs, config)
         if fs in failed_snapshots:
@@ -238,6 +221,8 @@ def main():
             continue
         if fs not in snapshots:
             continue
+        if not conf['weed_enable']:
+            continue
 
         kwargs = {k: int(v) for k, v in conf.items() if k in [
                 'keep_custom',
@@ -261,7 +246,60 @@ def main():
                 **kwargs)
 
 
+def main():
+    config = configparser.SafeConfigParser()
+    config.read('/etc/zsnapper.ini')
+    sudo = False
+    ret = RET_CODES['SUCCESS']
+    log = logging.getLogger(LOGGER)
 
+    if os.getuid() != 0:
+        sudo = True
+    
+    fslist = sorted(zsnaplib.get_filesystems(sudo))
+    snapshots = zsnaplib.get_snapshots(sudo)
+    
+    failed_snapshots = do_snapshots(fslist, snapshots, config, sudo)
+    if failed_snapshots:
+        ret = RET_CODES['ERROR']
+
+    lockfile = '/tmp/zsnapper.pid'
+    # This loop should run at most twice
+    while True:
+        try:
+            lockfd = os.open(lockfile, os.O_CREAT|os.O_EXCL|os.O_WRONLY, mode=0o640)
+            os.write(lockfd, "{}".format(os.getpid()).encode('utf-8'))
+            os.close(lockfd)
+            break
+        except OSError:
+            pass
+
+        # lock file exists, check if the pid seems valid
+        with open(lockfile, 'r') as f:
+            pid = f.read()
+        try:
+            pid = int(pid)
+            os.kill(pid, 0)
+            # If we got here the lock is owned by an existing pid
+            log.info('Previous run is not completed yet, will not send or weed snapshots')
+            return ret
+        except OSError:
+            # pid is not running, forcing unlock
+            os.remove(lockfile)
+        except ValueError:
+            log.error('lockfile {} exists but does not seem to contain a pid. Will not continue'.format(lockfile))
+            return RET_CODES['FAILED']
+
+
+    # reload all snapshots so we get our new snapshots here
+    snapshots = zsnaplib.get_snapshots(sudo)
+    failed_send = send_snapshots(fslist, snapshots, config, sudo)
+    if failed_send:
+        ret = RET_CODES['ERROR']
+
+    failed_snapshots.update(failed_send)
+    weed_snapshots(fslist, snapshots, config, sudo, failed_snapshots)
+    os.remove(lockfile)
 
 if __name__ == '__main__':
     log = logging.getLogger(LOGGER)
@@ -269,7 +307,10 @@ if __name__ == '__main__':
     handler = logging.StreamHandler()
     handler.setLevel(logging.WARNING)
     log.addHandler(handler)
+
     handler = logging.handlers.SysLogHandler(address='/dev/log')
+    formatter = logging.Formatter(fmt='zsnapper %(message)s')
+    handler.setFormatter(formatter)
     handler.setLevel(logging.INFO)
     log.addHandler(handler)
     sys.exit(main())

zsnaplib/__init__.py

@@ -212,69 +212,69 @@ def weed_snapshots(
                 keep['custom'].append(date)
 
     if keep_yearly:
-        saved['year'] = saved['year'][-keep_yearly:]
+        keep['year'] = keep['year'][-keep_yearly:]
     else:
-        saved['year'] = []
+        keep['year'] = []
     
     if keep_monthly:
-        saved['month'] = saved['month'][-keep_monthly:]
+        keep['month'] = keep['month'][-keep_monthly:]
     else:
-        saved['month'] = []
+        keep['month'] = []
 
     if keep_weekly:
-        saved['week'] = saved['week'][-keep_weekly:]
+        keep['week'] = keep['week'][-keep_weekly:]
     else:
-        saved['week'] = []
+        keep['week'] = []
 
     if keep_daily:
-        saved['day'] = saved['day'][-keep_daily:]
+        keep['day'] = keep['day'][-keep_daily:]
     else:
-        saved['day'] = []
+        keep['day'] = []
 
     if keep_hourly:
-        saved['hour'] = saved['hour'][-keep_hourly:]
+        keep['hour'] = keep['hour'][-keep_hourly:]
     else:
-        saved['hour'] = []
+        keep['hour'] = []
 
     if keep_30min:
-        saved['min30'] = saved['min30'][-keep_30min:]
+        keep['min30'] = keep['min30'][-keep_30min:]
     else:
-        saved['min30'] = []
+        keep['min30'] = []
 
     if keep_15min:
-        saved['min15'] = saved['min15'][-keep_15min:]
+        keep['min15'] = keep['min15'][-keep_15min:]
     else:
-        saved['min15'] = []
+        keep['min15'] = []
 
     if keep_5min:
-        saved['min5'] = saved['min5'][-keep_5min:]
+        keep['min5'] = keep['min5'][-keep_5min:]
     else:
-        saved['min5'] = []
+        keep['min5'] = []
 
     if keep_1min:
-        saved['min1'] = saved['min1'][-keep_1min:]
+        keep['min1'] = keep['min1'][-keep_1min:]
     else:
-        saved['min1'] = []
+        keep['min1'] = []
 
     if keep_custom:
-        saved['custom'] = saved['custom'][-keep_custom:]
+        keep['custom'] = keep['custom'][-keep_custom:]
     else:
-        saved['custom'] = []
+        keep['custom'] = []
 
-    all_saved = []
+    all_keep = []
-    all_saved.extend(saved['year'])
+    all_keep.extend(keep['year'])
-    all_saved.extend(saved['month'])
+    all_keep.extend(keep['month'])
-    all_saved.extend(saved['week'])
+    all_keep.extend(keep['week'])
-    all_saved.extend(saved['day'])
+    all_keep.extend(keep['day'])
-    all_saved.extend(saved['hour'])
+    all_keep.extend(keep['hour'])
-    all_saved.extend(saved['min30'])
+    all_keep.extend(keep['min30'])
-    all_saved.extend(saved['min15'])
+    all_keep.extend(keep['min15'])
-    all_saved.extend(saved['min5'])
+    all_keep.extend(keep['min5'])
-    all_saved.extend(saved['min1'])
+    all_keep.extend(keep['min1'])
-    all_saved.extend(saved['custom'])
+    all_keep.extend(keep['custom'])
-    all_saved = set(all_saved)
+    all_keep = set(all_keep)
 
-    to_remove = [date for date in dates if date not in all_saved]
+    to_remove = [date for date in dates if date not in all_keep]
     for date in to_remove:
         try:
             log.info('{}: removing snapshot from {}'.format(fs, date))

zsnapper.ini-sample

@@ -1,33 +1,60 @@
-[settings]
+# zsnapper sample configuration
-# NOTE:
+
-# --stdin is used to pass password to sudo, this does not work the first time
+# Each section is the name of a ZFS file system
-# a user uses sudo, so make sure to run a sudo command manually first
+# All settings are applied recursively to all file system descendants
 #
-# or preferably, leave this commented out and use NOPASSWD for sudo...
-;sudo=<password>
-
-
 [tank]
-# frequency of snapshots
+# Frequency of snapshots
+# Set to empty value to disable snapshoting
+# 
+# Interval units are 'd', 'h' and 'm' for days, hours and minutes.
+# they can also be combined if you for example wants a snapshot taken every 1 and a half days:
+;snapshot_interval=1d 12h
 snapshot_interval=1h
 
 # Remote replication
-# possible other value is 'latest' to only sync the last available snapshot
+# possible other value is 'latest' to only sync the latest snapshot
+# Set to empty value to not send the snapshots to remote
 remote_enable=all
 
+# The remote_zfs_cmd option is the command to use to execute zfs on target machine.
+# remote_test_cmd, if set, is executed before trying to send any snapshot to remote.
+# If remote_test_cmd returns a non-zero status the remote is considered to be unavailable
+# and no snapshots are sent. (A warning is written in the log though)
+#
 # NOTE:
-# The command arguments must not contain whitespace characters, since
+#  The command arguments must not contain whitespace characters, due to implementation details.
-# split() is used to create an array to subprocess.Popen()
+#
+# Variables can be used in remote_zfs_cmd and remote_test_cmd. Any setting
+# available in the section can be used as a variable
 remote_zfs_cmd=/usr/bin/ssh ${remote_user}@${remote_host} /usr/bin/sudo /sbin/zfs
 remote_test_cmd=/usr/bin/ssh ${remote_user}@${remote_host} echo "success"
+# The remote_host option is optional but recommended if you send snapshots to a remote host.
+remote_host=my.backup.server.tld
+# remote_user is not a actually a zsnapper option; but it's used as a variable in the remote commands.
 remote_user=backup
-remote_host=hem.winterbird.org
+
-remote_zfs_target=tank/backup/asuna/tank
+# remote_zfs_target is the file system on the remote client that should receive zfs sends
+# for this file system.
+# NOTE:
+#  Just like any other option this is inherited by file system descendants,
+#  but if a child has the same remote_zfs_target as the parent, the child 
+#  will instead use this to figure out where the parent is and be sent to 
+#  it position relative to the parent.
+#  For example: The local file system tank/ROOT will be sent to tank/backup/client/ROOT.
+remote_zfs_target=tank/backup/client
+
 # These can be set to use custom arguments to zfs send and zfs receive
-; remote_send_flags=-D -p
+remote_send_flags=-D -p
-remote_send_flags=
 remote_recv_flags=
 
+# snapshot weeding
+# set weed_enable to an empty value to disable snapshot weeding.
+# NOTE:
+#  If weeding is enabled but no keep_<time> setting is configured all 
+#  your snapshots, except the latest, will be removed. Make sure to 
+#  configure your weeding settings carefully.
+weed_enable=1
 keep_hourly=24
 keep_daily=7
 keep_weekly=4
@@ -39,7 +66,8 @@ snapshot_interval=
 remote_enable=
 
 [tank/media]
-snapshot_interval=15m
+snapshot_interval=
+remote_enable=
 
 [tank/tmp]
 snapshot_interval=