implement 'zfs destroy'

src/simplezfs/pe_helper.py

@@ -6,7 +6,7 @@ import stat
 import subprocess
 from typing import List, Optional
 
-from .exceptions import PEHelperException, ExternalPEHelperException
+from .exceptions import PEHelperException, ExternalPEHelperException, ValidationError
 from .validation import validate_dataset_path, validate_pool_name
 
 
@@ -39,6 +39,15 @@ class PEHelperBase:
         '''
         raise NotImplementedError(f'{self} has not implemented this function')
 
+    def zfs_destroy_dataset(self, dataset: str, recursive: bool, force_umount: bool):
+        '''
+        Destroy the given ``dataset``.
+
+        :raises ValidationError: If parameters do not validate.
+        :raises PEHelperException: If errors are encountered when running the helper.
+        '''
+        raise NotImplementedError(f'{self} has not implemented this function')
+
 
 class ExternalPEHelper(PEHelperBase):
     '''
@@ -156,3 +165,17 @@ class SudoPEHelper(PEHelperBase):
         # TODO validate mountpoint fs
 
         self._execute_cmd(['zfs', 'set', f'mountpoint={mountpoint}', fileset])
+
+    def zfs_destroy_dataset(self, dataset: str, recursive: bool, force_umount: bool) -> None:
+        if '/' not in dataset:
+            raise ValidationError('Can\'t remove the pool itself')
+        validate_dataset_path(dataset)
+
+        args = ['zfs', 'destroy', '-p']
+        if recursive:
+            args.append('-r')
+        if force_umount:
+            args.append('-f')
+        args.append(dataset)
+
+        self._execute_cmd(args)

src/simplezfs/zfs.py

@@ -651,7 +651,7 @@ class ZFS:
         '''
         raise NotImplementedError(f'{self} has not implemented this function')
 
-    def destroy_dataset(self, name: str, *, recursive: bool = False) -> None:
+    def destroy_dataset(self, dataset: str, *, recursive: bool = False, force_umount: bool = False) -> None:
         '''
         Destroy a dataset. This function tries to remove a dataset, optionally removing all children recursively if
         ``recursive`` is **True**. This function works on all types of datasets, ``fileset``, ``volume``, ``snapshot``
@@ -666,7 +666,30 @@ class ZFS:
 
         :note: This is a destructive process that can't be undone.
 
-        :param name: Name of the dataset to remove.
+        :param dataset: Name of the dataset to remove.
+        :param recursive: Whether to recursively delete child datasets such as snapshots.
+        :param force_umount: Forces umounting before destroying. Refer to ``ZFS(8)`` `zfs destroy` parameter ``-f``.
+        :raises ValidationError: If validating the parameters failed.
+        :raises DatasetNotFound: If the dataset can't be found.
+        '''
+        if '/' not in dataset:
+            raise ValidationError('Cannot destroy the pool using this function')
+        validate_dataset_path(dataset)
+
+        if not self.dataset_exists(dataset):
+            raise DatasetNotFound('The dataset could not be found')
+
+        self._destroy_dataset(dataset, recursive=recursive, force_umount=force_umount)
+
+    def _destroy_dataset(self, dataset: str, *, recursive: bool = False, force_umount: bool = False) -> None:
+        '''
+        Internal implementation of :func:`destroy_dataset`.
+
+        :param dataset: The name of the dataset to remove.
+        :param recursive: Whether to recursively delete child datasets such as snapshots.
+        :param force_umount: Forces umounting before destroying.
+        :raises ValidationError: If validating the parameters failed.
+        :raises DatasetNotFound: If the dataset can't be found.
         '''
         raise NotImplementedError(f'{self} has not implemented this function')
 

src/simplezfs/zfs_cli.py

@@ -323,3 +323,50 @@ class ZFSCli(ZFS):
     def create_bookmark(self, snapshot: str, name: str) -> Dataset:
         validate_dataset_path(snapshot)
         raise NotImplementedError()
+
+    def _destroy_dataset(self, dataset: str, *, recursive: bool = False, force_umount: bool = False) -> None:
+        args = [self.__exe, 'destroy', '-p']
+        if recursive:
+            args.append('-r')
+        if force_umount:
+            args.append('-f')
+        args.append(dataset)
+
+        log.debug(f'executing: {args}')
+        proc = subprocess.run(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, encoding='utf-8')
+        if proc.returncode != 0 or len(proc.stderr) > 0:
+            log.debug(f'destroy_dataset: command failed, code={proc.returncode}, stderr="{proc.stderr}"')
+            if 'has children' in proc.stderr:
+                if recursive:
+                    log.error(f'Dataset {dataset} has children and recursive was given, please report this')
+                else:
+                    log.warning(f'Dataset {dataset} has children and thus cannot be destroyed without recursive=True')
+                    raise Exception
+            # two possible messaes: (zfs destroy -p -r [-f] $fileset_with_snapshots)
+            # * 'cannot destroy snapshots: permission denied'
+            # * 'umount: only root can use "--types" option'
+            # The latter seems to originate from having `destroy` and `mount` via `zfs allow`.
+            elif ('cannot destroy' in proc.stderr and 'permission denied' in proc.stderr) or \
+                    'only root can' in proc.stderr:
+                log.debug('Command output indicates that we need to run the PE Helper')
+                if self.use_pe_helper:
+                    if self.pe_helper is not None:
+                        log.info(f'Using pe_helper to remove {dataset}')
+                        self.pe_helper.zfs_destroy_dataset(dataset, recursive, force_umount)
+                        log.info(f'Dataset {dataset} destroyed (using pe_helper)')
+                    else:
+                        msg = 'Cannot destroy: No pe_helper set'
+                        log.error(msg)
+                        raise PermissionError(msg)
+                else:
+                    log.error(f'Dataset "{dataset}" can\'t be destroyed due to lack of permissions. Please set a'
+                              ' PE helper')
+                    raise PermissionError(proc.stderr)
+            else:
+                try:
+                    self.handle_command_error(proc)
+                except PermissionError:
+                    log.error('Permission denied, please use "zfs allow"')
+                    raise
+        else:
+            log.info('Dataset destroyed successfully')