Talker crashes when it tries to publish on a topic it doesn't have permission to use

[sloretz]

Bug report

Required Info:

• Operating System:
  • Windows 10
• Installation type:
  • binaries
• Version or commit hash:
  • https://ci.ros2.org/view/packaging/job/packaging_windows/1043/
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • rclcpp, rclpy

Steps to reproduce issue

Policy file: https://raw.githubusercontent.com/ros2/sros2/ardent/examples/sample_policy.yaml

md C:\dev\sros2_demo
md C:\dev\sros2_demo\demo_keys
REM copy policy file as policies.yaml into demo_keys
cd C:\dev\sros2_demo
set RANDFILE=C:\dev\sros2_demo\.rnd

ros2 security create_keystore demo_keys
ros2 security create_key demo_keys talker
ros2 security create_key demo_keys listener
ros2 security create_permission demo_keys talker demo_keys/policies.yaml
ros2 security create_permission demo_keys listener demo_keys/policies.yaml

REM Launch the c++ talker
set ROS_SECURITY_ROOT_DIRECTORY=%cd%/demo_keys
set ROS_SECURITY_ENABLE=true
set ROS_SECURITY_STRATEGY=Enforce
ros2 run demo_nodes_cpp talker /chatter:=/something/else

REM next try rclpy
ros2 run demo_nodes_py talker /chatter:=/something/else

Expected behavior

Processes would exit with a non-zero return code

Actual behavior

Processes seem to crash (Windows dialog pops up saying process crashed)

Additional information

python talker manages to print a traceback before crashing

>ros2 run demo_nodes_py talker /chatter:=/something/else
Traceback (most recent call last):
  File "C:\dev\ros2-windows\lib\demo_nodes_py\talker-script.py", line 11, in <module>
    load_entry_point('demo-nodes-py==0.4.0', 'console_scripts', 'talker')()
  File "C:\dev\ros2-windows\Lib\site-packages\demo_nodes_py\topics\talker.py", line 46, in main
    node = Talker()
  File "C:\dev\ros2-windows\Lib\site-packages\demo_nodes_py\topics\talker.py", line 28, in __init__
    self.pub = self.create_publisher(String, 'chatter')
  File "C:\dev\ros2-windows\Lib\site-packages\rclpy\node.py", line 115, in create_publisher
    self.handle, msg_type, topic, qos_profile.get_c_qos_profile())
RuntimeError: Failed to create publisher: create_publisher() could not create publisher, at C:\J\workspace\packaging_windows\ws\src\ros2\rmw_fastrtps\rmw_fastrtps_cpp\src\rmw_publisher.cpp:132, at C:\J\workspace\packaging_windows\ws\src\ros2\rcl\rcl\src\rcl\publisher.c:173
[SECURITY

[mikaelarguedas]

This is currently expected behavior.
All failing python calls currently raise RuntimeError in rclpy (ros2/rclpy#31)

We could catch those but I'm not sure what the expected behavior is. Just return with non-zero without a specific error message ?

[dirk-thomas]

Many of our existing tools try / except RuntimeError in the main and print the error message to stderr and sys.exit with non-zero. It is used to signal "known" errors without showing the user a stacktrace.

[sloretz]

Exiting with a traceback is what I'd expect. What I don't expect is to see is this dialog. It does not normally appear when a node exits with a traceback.

Edit: and with c++ node

[mikaelarguedas]

Many of our existing tools try / except RuntimeError in the main and print the error message to stderr and sys.exit with non-zero. It is used to signal "known" errors without showing the user a stacktrace.

Sure, we can make a PR to the demos repo to catch all node creation failures in the python nodes 👍
It's moving away from them being minimalistic but I guess that's something we cannot work around

[dirk-thomas]

I think in this case it makes sense to keep the stacktrace since it is an "unexpected" error and the stacktrace help the user to determine where the problem is.

[mikaelarguedas]

@sloretz @dirk-thomas What is the next action item on this ?
Finding a way to silence the pop-up but keep the stacktrace ?

@sloretz do you have the same behavior with connext or only fastrtps?

[dirk-thomas]

Finding a way to silence the pop-up but keep the stacktrace ?

We have to understand why there is popup in the first place. I don't think that the Python code controls/triggers that.