Issue with RCLCPP THROTTLE logging in the plugin based approach

Bug report

Hello!

I've a plugin that I use it to perform some computations and return and this plugin runs at a higher frequency, and then to reduce spamming, I've changed the original logging with THROTTLE. It works fine as long as only one plugin is loaded in my system. If I load multiple plugins of the same type, it doesn't print the THROTTLE log of other plugins but only the first one even though they have different loggers with different names.

I believe this is caused by the fact that the RCLCPP_XXX_THROTTLE internally uses the following macro RCUTILS_LOG_CONDITION_THROTTLE_BEFORE and this is using some static variables inside. The condition for logging (i.e., if a certain duration has passed since the last log message) will remain the same, as this is determined by the code in the macro, not by the logger. The __rcutils_logging_last_logged variable, which keeps track of the last time a log message was outputted, is static and unique to each line where the macro is used. Therefore, even if you change the logger, the duration-based condition for logging will still be unique to each line.

https://github.com/ros2/rcutils/blob/cf3e9986a557e4c893eb718b90c77ce189494a11/resource/logging_macros.h.em#L182-L206

I think it makes sense to also consider the logger type to be same or not in the same check as well. In my current implementation, the logger name is changed depending on the name of the plugin, but not the type. This way it is unique for every plugin instance.

Required Info:

• Operating System:
  • Ubuntu 22.04 and 24.04
• Installation type:
  • Binaries

Expected behavior

Different loggers should have different throttles even if they are in the same line as the plugin

Actual behavior

Different loggers are throttles as one and the information is lost inside the plugin

Is there a workaround or a better approach in this case?

Start by reading rcutils/resource/logging_macros.h.em, especially the RCUTILS_LOG_CONDITION_THROTTLE_BEFORE logic referenced in the report, and trace how RCLCPP_XXX_THROTTLE reaches it. Verify the behavior with multiple plugin instances using different logger names; done means each logger has an independent throttle interval. The payload does not name a test file.