Add filters for shell cmdline

This change adds three filters that can be used to construct shell
command lines in roles.

* shell_arg_enabled - skips adding an arg if enabled=False.
* shell_arg_list - loops through a list to generate a list of command
                   line args.
* shell_logging_path - create a string to capture stdout/stderr to file.

Change-Id: I5dc43e703f7ebe2ca94f4cbf650a7dee3c93ab5f

plugins/filter/shell_args.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+# Copyright 2019 Red Hat, Inc.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+
+class FilterModule(object):
+    def filters(self):
+        return {
+            'shell_arg_enabled': self.shell_arg_enabled,
+            'shell_arg_list': self.shell_arg_list,
+            'shell_logging_path': self.shell_logging_path
+        }
+
+    def shell_arg_enabled(self, arg, enabled=True):
+        if not enabled:
+            return ''
+        return arg
+
+    def shell_arg_list(self, arg, parameter=None):
+        if not isinstance(arg, (list, tuple)):
+            arg = [arg]
+        return_value = []
+        for a in arg:
+            if parameter:
+                return_value.append("{} {}".format(parameter, a))
+            else:
+                return_value.append(a)
+        return ' '.join(return_value)
+
+    def shell_logging_path(self, location, combine=True, enabled=False):
+        output = ''
+        if not enabled:
+            return output
+        if combine:
+            output = "{} {}".format(output, '2>&1')
+        return "{} >{}".format(output, location)

tests/base.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2010-2011 OpenStack Foundation
+# Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from oslotest import base
+
+
+class TestCase(base.BaseTestCase):
+
+    """Test case base class for all unit tests."""

tests/plugins/filter/test_shell_args.py

@@ -0,0 +1,70 @@
+# Copyright 2019 Red Hat, Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import mock
+
+from tests import base as tests_base
+from plugins.filter import shell_args
+
+
+class TestShellArgsFilters(tests_base.TestCase):
+    def setUp(self):
+        super(TestShellArgsFilters, self).setUp()
+        self.filter = shell_args.FilterModule()
+
+    def test_shell_arg_enabled_default(self):
+        self.assertEqual('foo',
+                         self.filter.shell_arg_enabled('foo'))
+
+    def test_shell_arg_enabled_disabled(self):
+        self.assertEqual('',
+                         self.filter.shell_arg_enabled('foo', enabled=False))
+
+    def test_shell_arg_list_default(self):
+        arg = ['a', 'b']
+        expected = 'a b'
+        self.assertEqual(expected, self.filter.shell_arg_list(arg))
+
+    def test_shell_arg_list_string(self):
+        arg = 'a'
+        expected = 'a'
+        self.assertEqual(expected, self.filter.shell_arg_list(arg))
+
+    def test_shell_arg_list_param(self):
+        arg = ['a', 'b']
+        expected = '--p a --p b'
+        self.assertEqual(expected,
+                         self.filter.shell_arg_list(arg, parameter='--p'))
+
+    def test_shell_logging_path_default(self):
+        location = '/tmp/foo.log'
+        expected = ''
+        self.assertEqual(expected,
+                         self.filter.shell_logging_path(location))
+
+    def test_shell_logging_path_enabled(self):
+        location = '/tmp/foo.log'
+        expected = ' 2>&1 >/tmp/foo.log'
+        self.assertEqual(expected,
+                         self.filter.shell_logging_path(location,
+                                                        enabled=True))
+
+    def test_shell_logging_path_enabled_not_combined(self):
+        location = '/tmp/foo.log'
+        expected = ' >/tmp/foo.log'
+        self.assertEqual(expected,
+                         self.filter.shell_logging_path(location,
+                                                        combine=False,
+                                                        enabled=True))

zuul.d/layout.yaml

@@ -1,4 +1,6 @@
 - project:
+    templates:
+      - openstack-python3-ussuri-jobs
     check:
       jobs:
         - openstack-tox-linters