Programmatical assignment handling

This is a new and experimentary feature of Nuvolos, please provide us with feedback to make it better!
It is possible to collect assignments from a project using a command line tool currently available in applications from our support on request.
The name of the tool is nv_collect and it is indended to help you in programmatically collecting and handing back grading artfiacts.
Basic usage
The tool makes it possible to:
1.Collect assignments from all students to a folder in your instance.
2.Grade assignments using the otter-grader package if your project supports this.
3.Hand back assignments in a safe manner to all students with a single command.
A tutorial workflow integrated with Otter
This guide relies on using the otter-grader package and demonstrates how the otter tutorial found here can be adapted to the Nuvolos workflow. This package requires TexLive to function properly which is only available currently on request from our support.
In the guide we assume the following:
You have access to a JupyterLab image that supports TexLive, pandoc, otter-grader and you have installed nv-collect.
Obtain the otter tutorial
To get the files referred by the otter tutorial, open a JupyterLab terminal and hit
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wget https://otter-grader.readthedocs.io/en/latest/_static/tutorial.zip
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unzip tutorial.zip
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Modify demo.ipynb
The demo.ipynb file that is provided by otter-grader is not completely compatible with Nuvolos. The reason is that the demo assumes that the environment has a window system - this is not true in Nuvolos. In order to fix this issue, in the second cell  instead of
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%matplotlib inline
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make sure to have
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import matplotlib
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matplotlib.use('Agg')
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Run otter assign
Following the steps of the tutorial execute the following command in the directory where you unzipped the tutorial zipfile:
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otter assign demo.ipynb dist --v1
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This command creates a dist directory in which the artifacts required for the autograding and assignment distribution are added.
The dist/student/demo.ipynb file is the stripped-down, simplified, user-friendly file that your students will have to fill out.
Create an Assignment on Nuvolos
Please refer to our guide on creating assignments. Make sure to copy dist/student/demo.ipynb to some separate folder which you can safely stage and assign.
In our example, we copy the file from /files/otter-test/dist/student/demo.ipynb to /files/assignment_1/demo.ipynb, then we stage the entire folder and distribute it as an assignment to our students. We give the assignment the name "assignment_1" in Nuvolos when creating the assignment (this doesn't have to be the same as the folder name containing the assignment, but it is generally good practice to have the same). 
Collect hand-ins
Once the assignment deadline has passed, the assignments are ready to be collected. We use the following command available in the JupyterLab terminal to collect:
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nvcollect collect --assignment_name "assignment_1" --assignment_folder assignment_1 --target_folder /files/test_collect
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This tells the collect tool to gather from all students whatever is contained in the assignment_1 folder in the Nuvolos assignment called "assignment_1" and the collected files should be placed under /files/test_collect.
The directory structure will be as such:
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/files/test_collect
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+-- nvcollect_manifest.json
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+-- single_user_inst_<code1>
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|   +-- ...
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+-- single_user_inst_<code2>
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|   +-- ...
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Grade hand-ins
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In order to grade hand-ins we need to use the autograder.zip file generated in Step 3. To grade all collected assignments:
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nvcollect otter-grade --source_folder /files/test_collect --autograder_location /files/otter-test/dist/autograder/autograder.zip --relative_path demo.ipynb
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Observe the following:
source_folder is the same folder as provided as target_folder to the collection command.
You have to provide the absolute path of the autograder.zip file that belongs to the particular notebook file you want to grade.
The relative_path parameter tells the tool where to look for in each student submission directory for the notebook file that needs to be graded.
As an outcome of the grading, you get the following new items in the source_folder:
A grade.csv file which contains the score of each student.
A grade.csv file in each student folder which contains the score of the student.
Handing back
You might want to add additional artifacts to each students folders (either manually or programmatically). Once you are done with this, you can push back the results of the grading with the command
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nvcollect handback --source_folder /files/test_collect
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Notice that the source_folder here is the same folder to which we collected and then in which the grading process ran.