Troubleshoot: Rmf_adapter.easy_full_control ModuleNotFoundError

Hey guys! Let's dive into this bug report about a ModuleNotFoundError specifically hitting the rmf_adapter.easy_full_control module. It looks like the system is saying that rmf_adapter isn't a package, which is causing some headaches when trying to run the fleet_adapter_mir. We'll break down the issue, steps to reproduce it, and what's expected versus what's actually happening. So, let's get started!

Discussion Category

This issue falls under the open-rmf and fleet_adapter_mir categories, so it's definitely something related to the Robot Middleware Framework and its interaction with the MIR fleet adapter.

Issue Context

Before we dive deep, the reporter has confirmed that they've already searched for similar issues and discussions. This is a great first step to avoid duplicate reports and see if there's a known solution already out there. So, kudos to them for doing their homework!

Environment Details

To get a clear picture, here’s the setup where the bug is occurring:

• OS: Ubuntu 22.04
• Open-RMF Installation: Binaries
• Open-RMF Version: release-humble-231229
• ROS Distribution: Humble
• ROS Installation: Binaries
• Package: fleet_adapter_mir

Knowing the versions and installation methods helps narrow down potential conflicts or missing dependencies. It's like having a detailed map to navigate the problem!

Problem Description

The Core Issue

The main problem is that the fleet adapter fails to start. When the command ros2 run fleet_adapter_mir fleet_adapter_mir -h is executed, the node crashes immediately with a ModuleNotFoundError. The error message specifically complains about the missing rmf_adapter.easy_full_control module, indicating that rmf_adapter is not recognized as a package. This is a classic case of a Python import error, and we need to figure out why the module isn't being found.

Steps to Reproduce

To recreate this bug, follow these steps:

1. Source ROS 2 Humble: Make sure your ROS 2 environment is set up by sourcing the setup file: /opt/ros/humble/setup.bash
2. Source fleet_adapter_mir Workspace: Source the workspace where fleet_adapter_mir is installed. This ensures that ROS 2 can find the necessary packages and executables.
3. Run the Command: Execute the command that triggers the bug: ros2 run fleet_adapter_mir fleet_adapter_mir -h

By following these steps, anyone can try to reproduce the issue and confirm if it's a widespread problem or specific to the reporter's setup. It’s like a recipe for disaster, but in a good way—because we want to fix it!

Expected vs. Actual Behavior

• Expected Behavior: The command should display a help output detailing how to use the fleet_adapter_mir. This is the standard behavior for command-line tools when the -h or --help flag is used.
• Actual Behavior: Instead of the help output, the node crashes with the ModuleNotFoundError. This indicates a critical issue that prevents the adapter from even starting up. It’s like trying to start a car, but the engine won't even turn over.

Traceback Analysis

The traceback provides valuable clues about where the error occurs. Let's break it down:

Traceback (most recent call last):
  File "/home/sean-nr/mir_ws/install/fleet_adapter_mir/lib/fleet_adapter_mir/fleet_adapter_mir", line 33, in <module>
    sys.exit(load_entry_point('fleet-adapter-mir', 'console_scripts', 'fleet_adapter_mir')())
  File "/home/sean-nr/mir_ws/install/fleet_adapter_mir/lib/fleet_adapter_mir/fleet_adapter_mir", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "/usr/lib/python3.10/importlib/metadata/__init__.py", line 171, in load
    module = import_module(match.group('module'))
  File "/usr/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/home/sean-nr/mir_ws/build/fleet_adapter_mir/fleet_adapter_mir/fleet_adapter_mir.py", line 31, in <module>
    import rmf_adapter.easy_full_control as rmf_easy
ModuleNotFoundError: No module named 'rmf_adapter.easy_full_control'; 'rmf_adapter' is not a package
[ros2run]: Process exited with failure 1

• The traceback shows that the error occurs when trying to import rmf_adapter.easy_full_control in the fleet_adapter_mir.py file. This pinpoints the exact location of the problem.
• The message 'rmf_adapter' is not a package suggests that Python isn't recognizing rmf_adapter as a valid package, which could be due to installation issues, incorrect paths, or missing dependencies. It’s like trying to find a street, but the street sign is missing!

Additional Investigations

The reporter has also tried a source install of RMF after purging binary packages, but the issue persists. This eliminates the possibility of a simple binary installation problem. They also checked if the rmf_adapter module can be imported in a Python shell, which works fine. However, rmf_adapter.easy_full_control does not exist within the module. This is a crucial piece of information because it tells us that the module itself might be missing or not installed correctly. It's like finding the building, but the specific office you need isn't there.

Potential Causes and Solutions

Okay, guys, let's brainstorm some potential causes and how to tackle them:

1. Missing easy_full_control Module:

   • Cause: The easy_full_control module might not be included in the installed version of rmf_adapter. This could be due to an incomplete installation, a version mismatch, or the module being moved or renamed in a newer version. It’s like ordering a pizza, but a slice is missing!
   • Solution:
     • Verify Installation: Double-check that rmf_adapter is fully installed and that all submodules are included. You might need to reinstall the package to ensure everything is in place. Think of it as reassembling the puzzle to make sure no pieces are missing.
     • Check Versions: Ensure that the version of rmf_adapter being used is compatible with the fleet_adapter_mir. Sometimes, older versions might not have the required modules. It’s like trying to fit a square peg in a round hole.
     • Source Installation: If using a source installation, ensure that the workspace is correctly sourced and that the package is built properly. Sometimes, the build process might not complete successfully, leading to missing modules. This is like building a house but forgetting to put in a room!

2. Incorrect Python Path:

   • Cause: Python might not be looking in the correct location for the rmf_adapter package. This can happen if the PYTHONPATH environment variable is not set up correctly or if the package is installed in a non-standard location. It’s like trying to find your keys, but you're looking in the wrong drawer.
   • Solution:
     • Check PYTHONPATH: Verify that the PYTHONPATH includes the path to the rmf_adapter installation directory. You can check this by echoing the PYTHONPATH variable in the terminal: echo $PYTHONPATH. This is like checking your GPS to make sure you’re on the right route.
     • Source Workspace: Make sure you've sourced the correct workspace setup file. This usually adds the necessary paths to the environment variables. It's like putting on your glasses so you can see clearly.

3. Conflicting Installations:

   • Cause: There might be multiple installations of rmf_adapter or conflicting versions. This can confuse Python and lead to import errors. It’s like having two keys for the same door, but only one works.
   • Solution:
     • Purge and Reinstall: Try completely removing all rmf_adapter installations and then reinstalling it. This ensures a clean slate and avoids conflicts. Think of it as decluttering your desk so you can find what you need.
     • Virtual Environments: Consider using virtual environments to isolate package installations. This can prevent conflicts between different projects. It’s like having separate containers for different plants so they don’t interfere with each other.

4. Typographical Errors:

   • Cause: Sometimes, the issue can be as simple as a typo in the import statement. It’s easy to miss a small mistake, especially when you’re dealing with long module names. It's like mispelling a word in a search query.
   • Solution:
     • Double-Check Imports: Carefully review the import statement in fleet_adapter_mir.py to ensure there are no typos. Make sure the module name is spelled correctly and that the case matches. This is like proofreading your work before submitting it.

Next Steps

To further troubleshoot, I’d suggest the following:

• Detailed Reinstallation: Perform a clean reinstallation of rmf_adapter, ensuring all dependencies are met. Document each step to make sure nothing is missed.
• Environment Inspection: Thoroughly inspect the environment variables, especially PYTHONPATH, to confirm they are correctly set.
• Version Compatibility: Verify the compatibility of rmf_adapter with fleet_adapter_mir. Check the documentation or release notes for any version requirements.
• Minimal Example: Try importing rmf_adapter.easy_full_control in a minimal Python script outside of the fleet_adapter_mir context. This can help isolate whether the issue is specific to the adapter or a general import problem.

By systematically investigating these areas, we can hopefully nail down the root cause and get the fleet_adapter_mir up and running. Stay tuned for updates, and let's keep each other in the loop!

Additional Information or Screenshots

The reporter has provided a screenshot showing that while rmf_adapter can be imported, rmf_adapter.easy_full_control is not found. This reinforces the idea that the module might be missing or not correctly installed. A picture is worth a thousand words, right?

Hopefully, this detailed breakdown helps in resolving the issue. Let's get this bug squashed, guys!