Add --pre-snapshot-cmd and --post-snapshot-cmd options

zfs_autobackup/ZfsNode.py

@@ -161,7 +161,7 @@ class ZfsNode(ExecuteNode):
         """determine uniq new snapshotname"""
         return self.backup_name + "-" + time.strftime("%Y%m%d%H%M%S")
 
-    def consistent_snapshot(self, datasets, snapshot_name, min_changed_bytes):
+    def consistent_snapshot(self, datasets, snapshot_name, min_changed_bytes, pre_snapshot_cmd=None, post_snapshot_cmd=None):
         """create a consistent (atomic) snapshot of specified datasets, per pool.
         """
 
@@ -191,6 +191,10 @@ class ZfsNode(ExecuteNode):
             self.verbose("No changes anywhere: not creating snapshots.")
             return
 
+        if pre_snapshot_cmd:
+            self.verbose("Running pre-snapshot-cmd:\n\t{}".format(pre_snapshot_cmd))
+            self.run(cmd=pre_snapshot_cmd.split(" "), readonly=False)
+
         # create consistent snapshot per pool
         for (pool_name, snapshots) in pools.items():
             cmd = ["zfs", "snapshot"]
@@ -200,6 +204,10 @@ class ZfsNode(ExecuteNode):
             self.verbose("Creating snapshots {} in pool {}".format(snapshot_name, pool_name))
             self.run(cmd, readonly=False)
 
+        if post_snapshot_cmd:
+            self.verbose("Running post-snapshot-cmd:\n\t{}".format(post_snapshot_cmd))
+            self.run(cmd=post_snapshot_cmd.split(" "), readonly=False)
+
     def selected_datasets(self, exclude_received, exclude_paths):
         """determine filesystems that should be backupped by looking at the special autobackup-property, systemwide