Add new conditions for checking launch configuration values (#453) (#457

)

* Add new conditions for checking launch configuration values

Resolves #452

These are useful for conditioning launch file actions based on the values of launch configurations.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Fix doc typo

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

launch/launch/conditions/__init__.py

@@ -17,11 +17,15 @@
 from .evaluate_condition_expression_impl import evaluate_condition_expression
 from .if_condition import IfCondition
 from .invalid_condition_expression_error import InvalidConditionExpressionError
+from .launch_configuration_equals import LaunchConfigurationEquals
+from .launch_configuration_not_equals import LaunchConfigurationNotEquals
 from .unless_condition import UnlessCondition
 
 __all__ = [
     'evaluate_condition_expression',
     'IfCondition',
     'InvalidConditionExpressionError',
+    'LaunchConfigurationEquals',
+    'LaunchConfigurationNotEquals',
     'UnlessCondition',
 ]

launch/launch/conditions/launch_configuration_equals.py

@@ -0,0 +1,67 @@
+# Copyright 2020 Open Source Robotics Foundation, Inc.
+#
+# 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.
+
+"""Module for LaunchConfigurationEquals class."""
+
+from typing import Optional
+from typing import Text
+
+from ..condition import Condition
+from ..launch_context import LaunchContext
+from ..some_substitutions_type import SomeSubstitutionsType
+from ..utilities import normalize_to_list_of_substitutions
+from ..utilities import perform_substitutions
+
+
+class LaunchConfigurationEquals(Condition):
+    """
+    Condition on the value of a launch configuration.
+
+    This condition takes an optional string expression that is compared with the value of
+    a launch configuration.
+    If the value is equal to the launch configuration value, then this ``Condition``
+    evaluates to ``True``.
+    The expression may consist of :py:class:`launch.Substitution` instances.
+
+    If ``None`` is provided instead of a string expression, then the condition
+    evaluates to ``True`` if the launch configuration is not set.
+    """
+
+    def __init__(
+        self,
+        launch_configuration_name: SomeSubstitutionsType,
+        expected_value: Optional[SomeSubstitutionsType]
+    ) -> None:
+        self.__launch_configuration_name = launch_configuration_name
+        if expected_value is not None:
+            self.__expected_value = normalize_to_list_of_substitutions(expected_value)
+        else:
+            self.__expected_value = None
+        super().__init__(predicate=self._predicate_func)
+
+    def _predicate_func(self, context: LaunchContext) -> bool:
+        expanded_expected_value = None
+        if self.__expected_value is not None:
+            expanded_expected_value = perform_substitutions(context, self.__expected_value)
+        try:
+            value = context.launch_configurations[self.__launch_configuration_name]
+            return value == expanded_expected_value
+        except KeyError:
+            if expanded_expected_value is None:
+                return True
+        return False
+
+    def describe(self) -> Text:
+        """Return a description of this Condition."""
+        return self.__repr__()

launch/launch/conditions/launch_configuration_not_equals.py

@@ -0,0 +1,51 @@
+# Copyright 2020 Open Source Robotics Foundation, Inc.
+#
+# 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.
+
+"""Module for LaunchConfigurationNotEquals class."""
+
+from typing import Optional
+from typing import Text
+
+from .launch_configuration_equals import LaunchConfigurationEquals
+from ..launch_context import LaunchContext
+from ..some_substitutions_type import SomeSubstitutionsType
+
+
+class LaunchConfigurationNotEquals(LaunchConfigurationEquals):
+    """
+    Condition on the value of a launch configuration.
+
+    This condition takes an optional string expression that is compared with the value of
+    a launch configuration.
+    If the value is not equal to the launch configuration value, then this ``Condition``
+    evaluates to ``True``.
+    The expression may consist of :py:class:`launch.Substitution` instances.
+
+    If ``None`` is provided instead of a string expression, then the condition
+    evaluates to ``True`` if the launch configuration is set.
+    """
+
+    def __init__(
+        self,
+        launch_configuration_name: SomeSubstitutionsType,
+        expected_value: Optional[SomeSubstitutionsType]
+    ) -> None:
+        super().__init__(launch_configuration_name, expected_value)
+
+    def _predicate_func(self, context: LaunchContext) -> bool:
+        return not super()._predicate_func(context)
+
+    def describe(self) -> Text:
+        """Return a description of this Condition."""
+        return self.__repr__()

launch/test/launch/conditions/test_launch_configuration_equals.py

@@ -0,0 +1,53 @@
+# Copyright 2020 Open Source Robotics Foundation, Inc.
+#
+# 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.
+
+"""Tests for the LaunchConfigurationEquals condition class."""
+
+from launch.conditions import LaunchConfigurationEquals
+from launch.substitutions import TextSubstitution
+
+
+def test_launch_configuration_equals():
+    """Test LaunchConfigurationEquals class."""
+    class MockLaunchContext:
+
+        def perform_substitution(self, substitution):
+            return substitution.perform(self)
+
+        @property
+        def launch_configurations(self):
+            return {
+                'foo': 'foo_value',
+                'bar': 'bar_value',
+                'empty': '',
+            }
+
+    lc = MockLaunchContext()
+    test_cases = [
+        ('foo', 'foo_value', True),
+        ('bar', 'bar_value', True),
+        ('bar', 'foo_value', False),
+        ('bar', None, False),
+        ('empty', '', True),
+        ('empty', 'foo_value', False),
+        ('empty', None, False),
+        ('baz', None, True),
+        ('baz', 'foo_value', False),
+    ]
+
+    for name, value, expected in test_cases:
+        assert LaunchConfigurationEquals(
+            name,
+            [TextSubstitution(text=value)] if value is not None else None
+        ).evaluate(lc) is expected

launch/test/launch/conditions/test_launch_configuration_not_equals.py

@@ -0,0 +1,53 @@
+# Copyright 2020 Open Source Robotics Foundation, Inc.
+#
+# 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.
+
+"""Tests for the LaunchConfigurationNotEquals condition class."""
+
+from launch.conditions import LaunchConfigurationNotEquals
+from launch.substitutions import TextSubstitution
+
+
+def test_launch_configuration_not_equals():
+    """Test LaunchConfigurationNotEquals class."""
+    class MockLaunchContext:
+
+        def perform_substitution(self, substitution):
+            return substitution.perform(self)
+
+        @property
+        def launch_configurations(self):
+            return {
+                'foo': 'foo_value',
+                'bar': 'bar_value',
+                'empty': '',
+            }
+
+    lc = MockLaunchContext()
+    test_cases = [
+        ('foo', 'foo_value', False),
+        ('bar', 'bar_value', False),
+        ('bar', 'foo_value', True),
+        ('bar', None, True),
+        ('empty', '', False),
+        ('empty', 'foo_value', True),
+        ('empty', None, True),
+        ('baz', None, False),
+        ('baz', 'foo_value', True),
+    ]
+
+    for name, value, expected in test_cases:
+        assert LaunchConfigurationNotEquals(
+            name,
+            [TextSubstitution(text=value)] if value is not None else None
+        ).evaluate(lc) is expected