Add a dry-run option.

3 files changed, 34 insertions, 25 deletions

diff --git a/example.py b/example.py
index 1643a17..62e237f 100755
--- a/example.py
+++ b/example.py
@@ -20,6 +20,7 @@ def list_targets(tgts):
 # parse the commandline
 parser = argparse.ArgumentParser()
 parser.add_argument('-l', '--list-targets', action = 'store_true')
+parser.add_argument('-n', '--dry-run', action = 'store_true')
 parser.add_argument('targets', nargs = argparse.REMAINDER)
 args = parser.parse_args()
 
@@ -41,7 +42,7 @@ else:
     tgts_run = tgts
 
 repo = Repo()
-res = repo.backup(tgts_run)
+res = repo.backup(tgts_run, dry_run = args.dry_run)
 for tgt, tgt_res in res.target_results.items():
     if tgt_res.success:
         continue
diff --git a/lbup/repository.py b/lbup/repository.py
index a0caf75..8275910 100644
--- a/lbup/repository.py
+++ b/lbup/repository.py
@@ -55,7 +55,7 @@ class Repo:
         self.bup_dir  = bup_dir
         self.data_dir = data_dir
 
-    def backup(self, tgts, gen_par2 = True):
+    def backup(self, tgts, *, gen_par2 = True, dry_run = False):
         """
         Backup the supplied targets.
 
@@ -72,7 +72,7 @@ class Repo:
                 for tgt in tgts:
                     self._logger.info('Backing up %s...' % tgt.name)
                     try:
-                        res = tgt.save(self.data_dir)
+                        res = tgt.save(self.data_dir, dry_run)
                     except Exception as e:
                         self._logger.exception('Exception backing up %s: %s' % (tgt.name, str(e)))
                         res = StepResult(False, str(e).encode('utf-8'))
diff --git a/lbup/targets.py b/lbup/targets.py
index 4ce7110..8e817b9 100644
--- a/lbup/targets.py
+++ b/lbup/targets.py
@@ -79,7 +79,8 @@ class Target(ABC):
         if len(stderr) > 0:
             self._logger.debug('%s stderr: %s' % (name, sanitize(stderr)))
 
-    def _do_save(self, bup_exec, path_prefix = '', index_opts = None, save_opts = None):
+    def _do_save(self, bup_exec, dry_run, *,
+                 path_prefix = '', index_opts = None, save_opts = None):
         excludes = [path_prefix + '/' + e for e in self.excludes]
         dirs     = [path_prefix + '/' + d for d in self.dirs]
 
@@ -93,38 +94,45 @@ class Target(ABC):
         cmd.extend(['--exclude=%s' % e for e in excludes])
         cmd.extend(dirs)
 
-        self._logger.debug('Executing index command: ' + str(cmd))
-        res_idx = subprocess.run(cmd, capture_output = True)
-        self._log_command('Index', res_idx.returncode,
-                          res_idx.stdout, res_idx.stderr)
+        if dry_run:
+            self._logger.debug('Not executing index command: ' + str(cmd))
+        else:
+            self._logger.debug('Executing index command: ' + str(cmd))
+            res_idx = subprocess.run(cmd, capture_output = True)
+            self._log_command('Index', res_idx.returncode,
+                              res_idx.stdout, res_idx.stderr)
 
         # save
         cmd = bup_exec + ['save', '-n', self.name] + save_opts + dirs
-        self._logger.debug('Executing save command: ' + str(cmd))
-        res_save = subprocess.run(cmd, capture_output = True)
-        self._log_command('Save', res_save.returncode,
-                          res_save.stdout, res_save.stderr)
+        if dry_run:
+            self._logger.debug('Not executing save command: ' + str(cmd))
+        else:
+            self._logger.debug('Executing save command: ' + str(cmd))
+            res_save = subprocess.run(cmd, capture_output = True)
+            self._log_command('Save', res_save.returncode,
+                              res_save.stdout, res_save.stderr)
 
         retcode = 0
         output  = b''
-        if res_idx.returncode != 0:
-            retcode = res_idx.returncode
-            output += res_idx.stderr + res_idx.stdout
-        if res_save.returncode != 0:
-            retcode = res_save.returncode
-            output += res_save.stderr + res_save.stdout
+        if not dry_run:
+            if res_idx.returncode != 0:
+                retcode = res_idx.returncode
+                output += res_idx.stderr + res_idx.stdout
+            if res_save.returncode != 0:
+                retcode = res_save.returncode
+                output += res_save.stderr + res_save.stdout
 
         result = repository.StepResult(retcode == 0, output)
 
         return result
 
     @abstractmethod
-    def save(self, data_dir):
+    def save(self, data_dir, dry_run = False):
         pass
 
 class TargetLocal(Target):
-    def save(self, data_dir):
-        return self._do_save(['bup'])
+    def save(self, data_dir, dry_run = False):
+        return self._do_save(['bup'], dry_run)
 
 class TargetSSH(Target):
     _remote = None
@@ -178,13 +186,13 @@ class TargetSSH(Target):
             raise BackupException('Invalid BUP_DIR on the remote target: %s' % str(bupdir))
         return bupdir[0]
 
-    def save(self, data_dir):
+    def save(self, data_dir, dry_run = False):
         with _ssh_client.SSHConnection(self._remote) as ssh:
             remote_bupdir = self._resolve_remote_bupdir(ssh)
 
         bup_exec = ['bup', 'on', '%s@%s' % (self._remote.username, self._remote.host),
                     '-d', remote_bupdir]
-        return self._do_save(bup_exec)
+        return self._do_save(bup_exec, dry_run)
 
 class TargetSSHLXCLVM(TargetSSH):
     """
@@ -219,7 +227,7 @@ class TargetSSHLXCLVM(TargetSSH):
         return "%s{LXC:%s/%s@[%s]}{LVM:%s}" % (super().__str__(), self._lxc_containername,
                 self._lxc_username, str(self._parent_remote), self._snapshot_size)
 
-    def save(self, data_dir):
+    def save(self, data_dir, dry_run = False):
         with contextlib.ExitStack() as stack:
             parent    = stack.enter_context(_ssh_client.SSHConnection(self._parent_remote))
             container = stack.enter_context(_ssh_client.SSHConnection(self._remote))
@@ -320,7 +328,7 @@ class TargetSSHLXCLVM(TargetSSH):
             bup_exec = ['bup', 'on', '%s@%s' % (self._remote.username, self._remote.host),
                         '-d', container_bupdir]
             try:
-                ret = self._do_save(bup_exec, path_prefix = container_mountpoint,
+                ret = self._do_save(bup_exec, dry_run, path_prefix = container_mountpoint,
                                     save_opts = save_opts, index_opts = ['--no-check-device'])
             finally:
                 self._paramiko_exec_cmd(parent,