CLI/clustershell: allow to disable progress bars

* Expose in the clustershell module the possibility to disable the show
  of the progress bars during execution.
* Allow to disable the progress bars also in the CLI with a
  --no-progress flag.

Bug: T212783
Change-Id: Id745f0c86c82f909546f4654715566ae5afa19d5

cumin/cli.py

@@ -125,6 +125,7 @@ def get_parser():
     parser.add_argument('--dry-run', action='store_true',
                         help=('Do not execute any command, just return the list of matching hosts and exit. '
                               '[default: False]'))
+    parser.add_argument('--no-progress', action='store_true', help='Do not show the progress bars during execution.')
     parser.add_argument('--version', action='version', version='%(prog)s {version}'.format(version=cumin.__version__))
     parser.add_argument('-d', '--debug', action='store_true',
                         help=('Set log level to DEBUG. See also log_file in the configuration. [default: False]'))
@@ -401,6 +402,7 @@ def run(args, config):
                        for command in args.commands]
     worker.timeout = args.global_timeout
     worker.handler = args.mode
+    worker.progress_bars = not args.no_progress
     if args.output is not None:  # TODO: set the reporter to tqdm when releasing v5.0.0
         worker.reporter = TqdmQuietReporter
     worker.success_threshold = args.success_percentage / 100

cumin/tests/unit/transports/test_clustershell.py

@@ -214,6 +214,17 @@ class InvalidReporter:
         with pytest.raises(WorkerError, match='reporter must be a subclass of'):
             self.worker.reporter = InvalidReporter
 
+    def test_progress_bars_getter(self):
+        """Access to the progress_bars getter should return the current value."""
+        assert self.worker.progress_bars  # Current default
+        self.worker.progress_bars = False
+        assert not self.worker.progress_bars
+
+    def test_progress_bars_setter_invalid(self):
+        """Raise WorkerError if trying to set the progress_bars to an invalid value."""
+        with pytest.raises(WorkerError, match='progress_bars must be a boolean'):
+            self.worker.progress_bars = 'invalid'
+
     @staticmethod
     def iter_buffers():
         """A generator to simulate the buffer iteration of ClusterShell objects."""

cumin/transports/clustershell.py

@@ -44,6 +44,7 @@ def __init__(self, config: dict, target: Target) -> None:
         self.task = Task.task_self()  # Initialize a ClusterShell task
         self._handler_instance: Optional[Event.EventHandler] = None
         self._reporter: Type[BaseReporter] = TqdmReporter  # TODO: change this to NullReporter when releasing v5.0.0
+        self._progress_bars: bool = True  # TODO: change this to False when releasing v5.0.0
 
         # Set any ClusterShell task options
         for key, value in config.get('clustershell', {}).items():
@@ -70,7 +71,8 @@ def execute(self) -> int:
         # Schedule only the first command for the first batch, the following ones must be handled by the EventHandler
         reporter = self._reporter()  # Instantiate a new Reporter at each execution
         self._handler_instance = self.handler(  # pylint: disable=not-callable
-            self.target, self.commands, reporter=reporter, success_threshold=self.success_threshold)
+            self.target, self.commands, reporter=reporter, success_threshold=self.success_threshold,
+            progress_bars=self._progress_bars)
 
         self.logger.info(
             "Executing commands %s on '%d' hosts: %s", self.commands, len(self.target.hosts), self.target.hosts)
@@ -151,6 +153,19 @@ def reporter(self, value: Type['BaseReporter']) -> None:
 
         self._reporter = value
 
+    @property
+    def progress_bars(self) -> bool:
+        """Getter for the boolean progress_bars property."""
+        return self._progress_bars
+
+    @progress_bars.setter
+    def progress_bars(self, value: bool) -> None:
+        """Setter for the `progress_bars` property. The relative documentation is in the getter."""
+        if not isinstance(value, bool):
+            raise_error('progress_bars', 'must be a boolean', value)
+
+        self._progress_bars = value
+
 
 class Node:
     """Node class to represent each target node.

doc/source/introduction.rst

@@ -174,6 +174,8 @@ More complex example fine-tuning many of the parameters::
     # Change the worker's default reporter from the current default that outputs to stdout all commands stdout/err
     # outputs to the empty reporter that does nothing.
     worker.reporter = NullReporter
+    # Suppress the progress bars during execution
+    worker.progress_bars = False
     exit_code = worker.execute()
     for nodes, output in worker.get_results():
         print(nodes)