expose clock to cli

Signed-off-by: Emerson Knapp <eknapp@amazon.com>

ros2bag/ros2bag/verb/play.py

@@ -27,6 +27,13 @@
 from rosbag2_py import StorageOptions
 import yaml
 
+def positive_float(arg: str) -> float:
+    value = float(arg)
+    if value <= 0:
+        raise ValueError(f'Value {value} is less than or equal to zero.')
+    return value
+
+
 
 class PlayVerb(VerbExtension):
     """Play back ROS data from a bag."""
@@ -71,6 +78,10 @@ def add_arguments(self, parser, cli_name):  # noqa: D102
                  '  pragmas: [\"<setting_name>\" = <setting_value>]'
                  'Note that applicable settings are limited to read-only for ros2 bag play.'
                  'For a list of sqlite3 settings, refer to sqlite3 documentation')
+        parser.add_argument(
+            '--clock', type=positive_float, default=0,
+            help='Publish to /clock at a specific frequency in Hz, to act as a ROS Time Source. '
+                 'Value must be positive. Defaults to not publishing.')
 
     def main(self, *, args):  # noqa: D102
         qos_profile_overrides = {}  # Specify a valid default
@@ -104,6 +115,7 @@ def main(self, *, args):  # noqa: D102
         play_options.topic_qos_profile_overrides = qos_profile_overrides
         play_options.loop = args.loop
         play_options.topic_remapping_options = topic_remapping
+        play_options.clock_publish_frequency = args.clock
 
         player = Player()
         player.play(storage_options, play_options)

rosbag2_py/src/rosbag2_py/_transport.cpp

@@ -190,6 +190,7 @@ PYBIND11_MODULE(_transport, m) {
     &PlayOptions::setTopicQoSProfileOverrides)
   .def_readwrite("loop", &PlayOptions::loop)
   .def_readwrite("topic_remapping_options", &PlayOptions::topic_remapping_options)
+  .def_readwrite("clock_publish_frequency", &PlayOptions::clock_publish_frequency)
   ;
 
   py::class_<RecordOptions>(m, "RecordOptions")

rosbag2_transport/src/rosbag2_transport/player.cpp

@@ -229,16 +229,8 @@ void Player::prepare_clock(const PlayOptions & options)
     // should not own transport-based functionality
     std::chrono::duration<double> clock_period{1.0 / options.clock_publish_frequency};
     auto nanos = std::chrono::duration_cast<std::chrono::nanoseconds>(clock_period);
-    ROSBAG2_TRANSPORT_LOG_WARN("Nanos is %lu", nanos.count());
-    rclcpp::QoS clock_qos = rclcpp::QoS(1)
-      // offer as strict as possible, will match if only best_effort requested
-      .reliable()
-      // new joiner can get a clock sample immediately no matter when it was published
-      .transient_local()
-      // offer a deadline based on the current rate so that subscriptions can use it if wanted
-      .deadline(clock_period);
     clock_publisher_ = rosbag2_transport_->create_publisher<rosgraph_msgs::msg::Clock>(
-      "/clock", clock_qos);
+      "/clock", rclcpp::ClockQoS());
     clock_publish_timer_ = rosbag2_transport_->create_wall_timer(
       nanos, [this]() {
         auto msg = rosgraph_msgs::msg::Clock();