Service quiz autocorrection issue

Course Support ROS Basics In 5 Days (Python)
1

I submitted twice for this quiz, each time I got the below information. Also, it took so long time to grade the quiz. Two launch files launch start and call separately as instructed.

Correct Quiz
services_quiz pkg found
(mark: 1.0)
services_quiz pkg correctly compiled
(mark: 3.5)
move_bb8_in_square_custom service found
(mark: 6.0)
Your mark for this quiz is: 0

Any help?

2

Hi!

Before submitting the quiz, did you ensure that no program was running in the terminals? Running programs can interfere with the grader and often cause delays and errors like this.

3

There is no any other program running. I closed all of them. It still has this issue.

4

Is there any other help?

5

Let me dedicate some time to this later today. Something must be wrong.

In the meantime, you can check if everything has been named as stated in the instructions. If this is the case, then you can move on to other things while I investigate this case.

6

Thanks, I checked all the file names and all the file names are the same as instructed. I will move to the next topic now and thanks for the help. Please let me know when you have new information.

7

I’ve checked the grader logs for your quiz, it seems to be getting stuck at this point, going into an infinite loop perhaps:

step 1 go straight done
fisrt turn done
step 2 go straight done
second turn done
step 3 go straight done
third turn done
step 4 go straight done
step 1 go straight done
fisrt turn done
step 2 go straight done
second turn done
step 3 go straight done
third turn done
step 4 go straight done
step 1 go straight done
fisrt turn done
step 2 go straight done
second turn done
step 3 go straight done
third turn done
step 4 go straight done

Could you check your logic for possible infinite loops?

Also, this might be part of the problem: you have compiled your package with catkin build, but the grader is using cakin_make. Please do the following:

cd ~/catkin_ws
rm -rf build/ devel/
catkin_make

Please try these and let me know what you find.

8

The loop is not infinite, it is only three times, and two for small squares, and one is for the big square as instructed. I will remove build & devel files and rebuild with catkin_make to see whether it works.

9

I tried it but still have the same problem. It was stuck at the same point again! By the way, the five trials were used up ,could you reset it if possible?Thanks~

10

I will need to look into this in more depth. Something is definitely wrong somewhere and hard to find, and it most likely relates to your package.

I will find some time for this on Monday and will let you know when you can submit again.

11

I finally found the problem :cold_sweat: .

It was the spin() statement at the end of your bb8_move_custom_service_client.py file. This prevents the client code from exiting once done, and that’s why the grader was stuck.

Just remove that line and try again. Your trials have been restored.

It’s actually our fault, because we didn’t make this clear in the notes that the grader expects the client to exit once it’s done. I apologize. We’ll update that.

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12

Thanks for the great help and I deleted that line and resubmitted the quiz, it was working perfectly. Thanks~

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13

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