Tf2 exception handling in detections callback

[simutisernestas]

Bug report

Required Info:

• Operating System:
  • Ubuntu 20.04
• ROS2 Version:
  • Foxy binary
• DDS implementation:
  • Fast-RTPS

Steps to reproduce issue

If this function gets msg without specified frame_id, tf2 throws an exception, which is not handled.

def callback(self, msg):
    '''callback function for detection result'''

Error:

[INFO] [launch]: All log files can be found below /home/ernestas/.ros/log/2020-11-15-14-41-55-170412-ernestas-pc-47727
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [kf_hungarian_node-1]: process started with pid [47729]
[kf_hungarian_node-1] Traceback (most recent call last):
[kf_hungarian_node-1]   File "/home/ernestas/nav2_dyn/install/kf_hungarian_tracker/lib/kf_hungarian_tracker/kf_hungarian_node", line 33, in <module>
[kf_hungarian_node-1]     sys.exit(load_entry_point('kf-hungarian-tracker', 'console_scripts', 'kf_hungarian_node')())
[kf_hungarian_node-1]   File "/home/ernestas/nav2_dyn/build/kf_hungarian_tracker/kf_hungarian_tracker/kf_hungarian_node.py", line 257, in main
[kf_hungarian_node-1]     rclpy.spin(node)
[kf_hungarian_node-1]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/__init__.py", line 191, in spin
[kf_hungarian_node-1]     executor.spin_once()
[kf_hungarian_node-1]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 687, in spin_once
[kf_hungarian_node-1]     raise handler.exception()
[kf_hungarian_node-1]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/task.py", line 239, in __call__
[kf_hungarian_node-1]     self._handler.send(None)
[kf_hungarian_node-1]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 407, in handler
[kf_hungarian_node-1]     await call_coroutine(entity, arg)
[kf_hungarian_node-1]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 332, in _execute_subscription
[kf_hungarian_node-1]     await await_or_execute(sub.callback, msg)
[kf_hungarian_node-1]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 118, in await_or_execute
[kf_hungarian_node-1]     return callback(*args)
[kf_hungarian_node-1]   File "/home/ernestas/nav2_dyn/build/kf_hungarian_tracker/kf_hungarian_tracker/kf_hungarian_node.py", line 101, in callback
[kf_hungarian_node-1]     trans = self.tf_buffer.lookup_transform(self.global_frame, msg.header.frame_id, rclpy.time.Time())
[kf_hungarian_node-1]   File "/home/ernestas/nav2_dyn/install/tf2_ros/lib/python3.8/site-packages/tf2_ros/buffer.py", line 112, in lookup_transform
[kf_hungarian_node-1]     return self.lookup_transform_core(target_frame, source_frame, time)
[kf_hungarian_node-1] tf2.InvalidArgumentException: Invalid argument "" passed to lookupTransform argument source_frame - in tf2 frame_ids cannot be empty
[ERROR] [kf_hungarian_node-1]: process has died [pid 47729, exit code 1, cmd '/home/ernestas/nav2_dyn/install/kf_hungarian_tracker/lib/kf_hungarian_tracker/kf_hungarian_node --ros-args -r __node:=kf_hungarian_node --params-file /home/ernestas/nav2_dyn/install/kf_hungarian_tracker/share/kf_hungarian_tracker/config/kf_hungarian.yaml'].

Expected behavior

All possible tf2 exceptions should be considered.

Actual behavior

Node crash.