Switch to using a context manager for the python examples. (#700)

That way we can be sure to always clean up, but use less
code doing so.

Signed-off-by: Chris Lalancette <[email protected]>

examples_tf2_py/examples_tf2_py/async_waits_for_transform.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import rclpy
+from rclpy.executors import ExternalShutdownException
 from rclpy.node import Node
 import rclpy.time
 from tf2_ros import LookupException
@@ -62,10 +63,9 @@ async def on_timer(self):
 
 
 def main():
-    rclpy.init()
-    node = AsyncWaitsForTransform()
     try:
-        rclpy.spin(node)
-    except KeyboardInterrupt:
+        with rclpy.init():
+            node = AsyncWaitsForTransform()
+            rclpy.spin(node)
+    except (KeyboardInterrupt, ExternalShutdownException):
         pass
-    rclpy.shutdown()

examples_tf2_py/examples_tf2_py/blocking_waits_for_transform.py

@@ -14,6 +14,7 @@
 
 import rclpy
 from rclpy.duration import Duration
+from rclpy.executors import ExternalShutdownException, MultiThreadedExecutor
 from rclpy.node import Node
 import rclpy.time
 from tf2_ros import LookupException
@@ -55,16 +56,12 @@ def on_timer(self):
 
 
 def main():
-    from rclpy.executors import MultiThreadedExecutor
-
-    rclpy.init()
-    node = BlockingWaitsForTransform()
-    # this node blocks in a callback, so a MultiThreadedExecutor is required
-    executor = MultiThreadedExecutor()
-    executor.add_node(node)
     try:
-        executor.spin()
-    except KeyboardInterrupt:
+        with rclpy.init():
+            node = BlockingWaitsForTransform()
+            # this node blocks in a callback, so a MultiThreadedExecutor is required
+            executor = MultiThreadedExecutor()
+            executor.add_node(node)
+            executor.spin()
+    except (KeyboardInterrupt, ExternalShutdownException):
         pass
-    executor.shutdown()
-    rclpy.shutdown()

examples_tf2_py/examples_tf2_py/dynamic_broadcaster.py

@@ -16,6 +16,7 @@
 
 from geometry_msgs.msg import TransformStamped
 import rclpy
+from rclpy.executors import ExternalShutdownException, SingleThreadedExecutor
 from rclpy.node import Node
 from rclpy.qos import QoSProfile
 from sensor_msgs.msg import JointState
@@ -87,20 +88,16 @@ def on_timer(self):
 
 
 def main():
-    rclpy.init()
-    nodes = []
-    nodes.append(DynamicFramePublisher())
-    nodes.append(FakeJointStatePublisher())
+    try:
+        with rclpy.init():
+            nodes = []
+            nodes.append(DynamicFramePublisher())
+            nodes.append(FakeJointStatePublisher())
 
-    from rclpy.executors import SingleThreadedExecutor
-    executor = SingleThreadedExecutor()
-    for node in nodes:
-        executor.add_node(node)
+            executor = SingleThreadedExecutor()
+            for node in nodes:
+                executor.add_node(node)
 
-    try:
-        executor.spin()
-    except KeyboardInterrupt:
+            executor.spin()
+    except (KeyboardInterrupt, ExternalShutdownException):
         pass
-
-    executor.shutdown()
-    rclpy.shutdown()

examples_tf2_py/examples_tf2_py/frame_dumper.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import rclpy
+from rclpy.executors import ExternalShutdownException
 from rclpy.node import Node
 from tf2_ros.buffer import Buffer
 from tf2_ros.transform_listener import TransformListener
@@ -34,11 +35,9 @@ def on_timer(self):
 
 
 def main():
-    rclpy.init()
-    node = FrameDumper()
     try:
-        rclpy.spin(node)
-    except KeyboardInterrupt:
+        with rclpy.init():
+            node = FrameDumper()
+            rclpy.spin(node)
+    except (KeyboardInterrupt, ExternalShutdownException):
         pass
-
-    rclpy.shutdown()

examples_tf2_py/examples_tf2_py/static_broadcaster.py

@@ -16,6 +16,7 @@
 
 from geometry_msgs.msg import TransformStamped
 import rclpy
+from rclpy.executors import ExternalShutdownException
 from rclpy.node import Node
 from tf2_ros.static_transform_broadcaster import StaticTransformBroadcaster
 
@@ -109,11 +110,9 @@ def make_transforms(self):
 
 
 def main():
-    rclpy.init()
-    node = StaticFramePublisher()
     try:
-        rclpy.spin(node)
-    except KeyboardInterrupt:
+        with rclpy.init():
+            node = StaticFramePublisher()
+            rclpy.spin(node)
+    except (KeyboardInterrupt, ExternalShutdownException):
         pass
-
-    rclpy.shutdown()

examples_tf2_py/examples_tf2_py/waits_for_transform.py

@@ -15,6 +15,7 @@
 import threading
 
 import rclpy
+from rclpy.executors import ExternalShutdownException
 from rclpy.node import Node
 import rclpy.time
 from tf2_ros import LookupException
@@ -73,10 +74,9 @@ def on_timer(self):
 
 
 def main():
-    rclpy.init()
-    node = WaitsForTransform()
     try:
-        rclpy.spin(node)
-    except KeyboardInterrupt:
+        with rclpy.init():
+            node = WaitsForTransform()
+            rclpy.spin(node)
+    except (KeyboardInterrupt, ExternalShutdownException):
         pass
-    rclpy.shutdown()

test_tf2/test/test_buffer_client.py

@@ -59,6 +59,9 @@ def setUpClass(cls):
 
     @classmethod
     def tearDownClass(cls):
+        cls.executor.remove_node(cls.node)
+        cls.node.destroy_node()
+        cls.executor.shutdown()
         rclpy.shutdown(context=cls.context)
 
     def setUp(self):

tf2_ros_py/test/test_buffer_client.py

@@ -112,6 +112,8 @@ def setup_class(cls):
 
     @classmethod
     def teardown_class(cls):
+        cls.executor.remove_node(cls.node)
+        cls.executor.shutdown()
         cls.mock_action_server.destroy()
         cls.node.destroy_node()
         rclpy.shutdown(context=cls.context)

tf2_ros_py/test/test_listener_and_broadcaster.py

@@ -73,6 +73,7 @@ def setup_class(cls):
 
     @classmethod
     def teardown_class(cls):
+        cls.executor.remove_node(cls.node)
         cls.node.destroy_node()
         rclpy.shutdown()