Retrieve n latest validation results

New optional parameter for the CLI limiting
number of validation results returned by history subcommand.

Resolves: rhbz#1944872

Signed-off-by: Jiri Podivin <jpodivin@redhat.com>
Change-Id: Ie79062e85351ed545c33001866773bf38fdf8517

validations_libs/cli/history.py

@@ -17,6 +17,7 @@
 import json
 import os
 import sys
+from argparse import ArgumentError
 
 from cliff.command import Command
 from cliff.lister import Lister
@@ -36,6 +37,15 @@ class ListHistory(Lister):
                             metavar="<validation>",
                             type=str,
                             help='Display execution history for a validation')
+        parser.add_argument('--limit',
+                            dest='history_limit',
+                            type=int,
+                            default=15,
+                            help=(
+                                'Display <n> most recent '
+                                'runs of the selected <validation>. '
+                                '<n> must be > 0\n'
+                                'The default display limit is set to 15.\n'))
         parser.add_argument('--validation-log-dir', dest='validation_log_dir',
                             default=constants.VALIDATIONS_LOG_BASEDIR,
                             help=("Path where the validation log files "
@@ -43,8 +53,24 @@ class ListHistory(Lister):
         return parser
 
     def take_action(self, parsed_args):
+
+        if parsed_args.history_limit < 1:
+            raise ValueError(
+                (
+                    "Number <n> of the most recent runs must be > 0. "
+                    "You have provided {}").format(
+                        parsed_args.history_limit))
+        self.app.LOG.info(
+            (
+                "Limiting output to the maximum of "
+                "{} last validations.").format(
+                parsed_args.history_limit))
+
         actions = ValidationActions(parsed_args.validation_log_dir)
-        return actions.show_history(parsed_args.validation)
+
+        return actions.show_history(
+            validation_ids=parsed_args.validation,
+            history_limit=parsed_args.history_limit)
 
 
 class GetHistory(Command):

validations_libs/tests/test_validation_actions.py

@@ -368,6 +368,47 @@ class TestValidationActions(TestCase):
                                    '2019-11-25T13:40:14.404623Z',
                                    '0:00:03.753')])
 
+    @mock.patch('os.stat')
+    @mock.patch('validations_libs.validation_logs.ValidationLogs.'
+                'get_all_logfiles',
+                return_value=[
+                    '/tmp/123_foo_2020-03-30T13:17:22.447857Z.json',
+                    '/tmp/123_bar_2020-03-05T13:17:22.447857Z.json'])
+    @mock.patch('json.load',
+                return_value=fakes.VALIDATIONS_LOGS_CONTENTS_LIST[0])
+    @mock.patch('six.moves.builtins.open')
+    def test_show_history_most_recent(self, mock_open, mock_load,
+                                      mock_get_log, mock_stat):
+
+        first_validation = mock.MagicMock()
+        second_validation = mock.MagicMock()
+
+        first_validation.st_mtime = 5
+        second_validation.st_mtime = 7
+
+        validations = {
+            '/tmp/123_foo_2020-03-30T13:17:22.447857Z.json': first_validation,
+            '/tmp/123_bar_2020-03-05T13:17:22.447857Z.json': second_validation
+        }
+
+        def _generator(x=None):
+            if x:
+                return validations[x]
+            return first_validation
+
+        mock_stat.side_effect = _generator
+
+        v_actions = ValidationActions()
+        col, values = v_actions.show_history(history_limit=1)
+
+        self.assertEqual(col, ('UUID', 'Validations',
+                               'Status', 'Execution at',
+                               'Duration'))
+        self.assertEqual(values, [('008886df-d297-1eaa-2a74-000000000008',
+                                   '512e', 'PASSED',
+                                   '2019-11-25T13:40:14.404623Z',
+                                   '0:00:03.753')])
+
     @mock.patch('validations_libs.validation_logs.ValidationLogs.'
                 'get_logfile_by_validation',
                 return_value=['/tmp/123_foo_2020-03-30T13:17:22.447857Z.json'])

validations_libs/validation_actions.py

@@ -203,6 +203,22 @@ class ValidationActions(object):
                     return None, _hosts
         return playbook, limit_hosts
 
+    def _retrieve_latest_results(self, logs, history_limit):
+        """Retrieve the most recent validation results.
+        Previously retrieved logs are sorted in ascending order,
+        with the last time the file was modified serving as a key.
+        Finally we take the last `n` logs, where `n` == `history_limit`
+        and return them while discarding the time information.
+        """
+
+        history_limit = min(history_limit, len(logs))
+
+        logs = sorted(
+                [(os.stat(path).st_mtime, path) for path in logs],
+                key=lambda path: path[0])
+
+        return [path[1] for path in logs[-history_limit:]]
+
     def run_validations(self, validation_name=None, inventory='localhost',
                         group=None, extra_vars=None, validations_dir=None,
                         extra_env_vars=None, ansible_cfg=None, quiet=True,
@@ -500,7 +516,8 @@ class ValidationActions(object):
         return params
 
     def show_history(self, validation_ids=None, extension='json',
-                     log_path=constants.VALIDATIONS_LOG_BASEDIR):
+                     log_path=constants.VALIDATIONS_LOG_BASEDIR,
+                     history_limit=None):
         """Return validation executions history
 
         :param validation_ids: The validation ids
@@ -509,6 +526,9 @@ class ValidationActions(object):
         :type extension: ``string``
         :param log_path: The absolute path of the validations logs directory
         :type log_path: ``string``
+        :param history_limit: The number of most recent history logs
+                              to be displayed.
+        :type history_limit: ``int``
 
         :return: Returns the information about the validation executions
                  history
@@ -559,10 +579,15 @@ class ValidationActions(object):
                 validation_ids = [validation_ids]
             logs = []
             for validation_id in validation_ids:
-                logs.extend(vlogs.get_logfile_by_validation(validation_id))
+                logs.extend(
+                    vlogs.get_logfile_by_validation(
+                        validation_id))
         else:
             logs = vlogs.get_all_logfiles(extension)
 
+        if history_limit and history_limit < len(logs):
+            logs = self._retrieve_latest_results(logs, history_limit)
+
         values = []
         column_name = ('UUID', 'Validations',
                        'Status', 'Execution at',