support ros2 topic pub yaml file input

ros2topic/ros2topic/verb/pub.py

@@ -70,6 +70,10 @@ def add_arguments(self, parser, cli_name):
         group.add_argument(
             '--stdin', action='store_true',
             help='Read values from standard input')
+        group.add_argument(
+            '--yaml-file', type=str, default=None,
+            help='YAML file that has message contents, '
+                 'e.g STDOUT from ros2 topic echo <topic>')
         parser.add_argument(
             '-r', '--rate', metavar='N', type=positive_float, default=1.0,
             help='Publishing rate in Hz (default: 1)')
@@ -131,6 +135,7 @@ def main(args):
             args.message_type,
             args.topic_name,
             values,
+            args.yaml_file,
             1. / args.rate,
             args.print,
             times,
@@ -146,6 +151,7 @@ def publisher(
     message_type: MsgType,
     topic_name: str,
     values: dict,
+    yaml_file: str,
     period: float,
     print_nth: int,
     times: int,
@@ -159,9 +165,14 @@ def publisher(
         msg_module = get_message(message_type)
     except (AttributeError, ModuleNotFoundError, ValueError):
         raise RuntimeError('The passed message type is invalid')
-    values_dictionary = yaml.safe_load(values)
-    if not isinstance(values_dictionary, dict):
-        return 'The passed value needs to be a dictionary in YAML format'
+
+    msg_reader = None
+    if yaml_file:
+        msg_reader = read_msg_from_yaml(yaml_file)
+    else:
+        values_dictionary = yaml.safe_load(values)
+        if not isinstance(values_dictionary, dict):
+            return 'The passed value needs to be a dictionary in YAML format'
 
     pub = node.create_publisher(msg_module, topic_name, qos_profile)
 
@@ -184,15 +195,38 @@ def publisher(
         total_wait_time += DEFAULT_WAIT_TIME
 
     msg = msg_module()
-    try:
-        timestamp_fields = set_message_fields(
-            msg, values_dictionary, expand_header_auto=True, expand_time_now=True)
-    except Exception as e:
-        return 'Failed to populate field: {0}'.format(e)
+    timestamp_fields = None
+
+    if not msg_reader:
+        # Set the static message from specified values once
+        try:
+            timestamp_fields = set_message_fields(
+                msg, values_dictionary, expand_header_auto=True, expand_time_now=True)
+        except Exception as e:
+            return 'Failed to populate field: {0}'.format(e)
+
     print('publisher: beginning loop')
     count = 0
+    more_message = True
 
     def timer_callback():
+        if msg_reader:
+            # Try to read out the contents for each message
+            try:
+                one_msg = next(msg_reader)
+                if not isinstance(one_msg, dict):
+                    print('The contents in YAML file need to be a YAML format')
+            except StopIteration:
+                nonlocal more_message
+                more_message = False
+                return
+            # Set the message with contents
+            try:
+                nonlocal timestamp_fields
+                timestamp_fields = set_message_fields(
+                    msg, one_msg, expand_header_auto=True, expand_time_now=True)
+            except Exception as e:
+                return 'Failed to populate field: {0}'.format(e)
         stamp_now = node.get_clock().now().to_msg()
         for field_setter in timestamp_fields:
             field_setter(stamp_now)
@@ -205,11 +239,20 @@ def timer_callback():
     timer_callback()
     if times != 1:
         timer = node.create_timer(period, timer_callback)
-        while times == 0 or count < times:
+        while (times == 0 or count < times) and more_message:
             rclpy.spin_once(node)
         # give some time for the messages to reach the wire before exiting
         time.sleep(keep_alive)
         node.destroy_timer(timer)
     else:
         # give some time for the messages to reach the wire before exiting
         time.sleep(keep_alive)
+
+
+def read_msg_from_yaml(yaml_file):
+    with open(yaml_file, 'r') as f:
+        for document in yaml.load_all(f, Loader=yaml.FullLoader):
+            if document is None:
+                continue  # Skip if there's no more document
+
+            yield document

ros2topic/test/resources/chatter.yaml

@@ -0,0 +1,10 @@
+---
+data: 'Hello ROS Users'
+---
+---
+data: Hello ROS Developers
+---
+data: Hello ROS Developers
+---
+---
+data: 'Hello ROS Users'

ros2topic/test/test_echo_pub.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import functools
+import pathlib
 import sys
 import unittest
 
@@ -49,6 +50,8 @@
 TEST_NODE = 'cli_echo_pub_test_node'
 TEST_NAMESPACE = 'cli_echo_pub'
 
+TEST_RESOURCES_DIR = pathlib.Path(__file__).resolve().parent / 'resources'
+
 
 @pytest.mark.rostest
 @launch_testing.markers.keep_alive
@@ -294,6 +297,42 @@ def test_pub_times(self, launch_service, proc_info, proc_output):
             strict=True
         )
 
+    @launch_testing.markers.retry_on_failure(times=5)
+    def test_pub_yaml(self, launch_service, proc_info, proc_output):
+        command_action = ExecuteProcess(
+            # yaml file prevails to the values 'data: hello'
+            cmd=(['ros2', 'topic', 'pub', '/clitest/topic/chatter',
+                  'std_msgs/String', '--yaml-file',
+                  str(TEST_RESOURCES_DIR / 'chatter.yaml')]),
+            additional_env={
+                'PYTHONUNBUFFERED': '1'
+            },
+            output='screen'
+        )
+        with launch_testing.tools.launch_process(
+            launch_service, command_action, proc_info, proc_output,
+            output_filter=launch_testing_ros.tools.basic_output_filter(
+                filtered_rmw_implementation=get_rmw_implementation_identifier()
+            )
+        ) as command:
+            assert command.wait_for_shutdown(timeout=10)
+        assert command.exit_code == launch_testing.asserts.EXIT_OK
+        assert launch_testing.tools.expect_output(
+            expected_lines=[
+                'publisher: beginning loop',
+                "publishing #1: std_msgs.msg.String(data='Hello ROS Users')",
+                '',
+                "publishing #2: std_msgs.msg.String(data='Hello ROS Developers')",
+                '',
+                "publishing #3: std_msgs.msg.String(data='Hello ROS Developers')",
+                '',
+                "publishing #4: std_msgs.msg.String(data='Hello ROS Users')",
+                '',
+            ],
+            text=command.output,
+            strict=True
+        )
+
     @launch_testing.markers.retry_on_failure(times=5)
     def test_echo_basic(self, launch_service, proc_info, proc_output):
         params = [