courseraprogramming 0.13.0

A toolkit to help develop asynchronous graders for Coursera based on docker images.

This command-line tool is a software development toolkit to help instructional teams author asynchronous graders for Coursera (typically programming assignments). Coursera’s asynchronous grading environment is based upon docker. While use of this tool is by no means required to develop the docker container images, we believe it is helpful in the endeavour. See below for brief descriptions of this tool’s capabilities.

Installation

To install this sdk, simply execute:

sudo pip install courseraprogramming

pip is a python package manager. If you do not have pip installed on your machine, please follow the installation instructions for your platform found at: <https://pip.pypa.io/en/latest/installing.html#install-or-upgrade-pip>

The tool includes its own usage information and documentation. Simply run:

courseraprogramming -h

or:

courseraprogramming --help

for a complete list of features, flags, and documentation.

Note: the tool requires docker to already be installed on your machine. Please see the docker installation instructions for further information.

Subcommands

sanity

Runs a number of sanity checks on your development environment and the Dockerfile that builds your grader to help catch pitfalls early.

Examples:

• courseraprogramming sanity checks the python and docker environment for successful basic operations.

• courseraprogramming sanity --skip-environment -f ./Dockerfile skips the environment checks, but runs a number of checks against the Dockerfile to help users avoid authoring pitfalls.

• courseraprogramming sanity --help displays usage for the sanity subcommand.

ls & cat

These subcommands help you verify that a built docker container image actually has what you expect inside of it. You can use these commands to poke at the file system and verify that everything is where it should be.

Examples:

• courseraprogramming ls $MY_CONTAINER_IMAGE /path/to/dir

• courseraprogramming cat $MY_CONTAINER_IMAGE /path/to/MyFile.sh

• courseraprogramming cat --help

inspect

Allows for interactive inspection of your docker grading container image to help debug grader issues. By default, it provides a shell that runs in a simulation of the hardened sandbox environment.

Examples:

• courseraprogramming inspect $MY_CONTAINER_IMAGE launches a basic shell within the container running as a deprivileged user, with memory constraints and the network configured similar to the production environment.

• courseraprogramming inspect --super-user --unlimited-memory --allow-network $MY_CONTAINER_IMAGE launches a shell running as a root user with the production-simulating constraints removed.

• courseraprogramming inspect -d /path/to/sample/submission $MY_CONTAINER_IMAGE launches a container mapping the sample submission on the host into the grading container. If you interactively invoke the configured grading script and interactively debug your grader.

• courseraprogramming inspect -h displays a list of all arguments and flags that can be passed to the inspect subcommand.

grade

This grade subcommand loosely replicates the production grading environment on your local machine, including applying CPU and memory limits, running as the correct user id, mounting the external file systems correctly, and relinquishing the appropriate extra linux capabilities. Note that because the GrID system has adopted a defense-in-depth or layered defensive posture, not all layers of the production environment can be faithfully replicated locally.

The grade subcommand has 2 sub-sub-commands. local runs a local grader container image on a sample submission found on the local file system. The future remote sub-sub-command will run a local grader container image on a sample submission downloaded from Coursera.org. This sub-sub-command is intended to help instructional teams verify new versions of their graders correctly handle problematic submissions.

Examples:

• courseraprogramming grade local $MY_CONTAINER_IMAGE /path/to/sample/submission/ invokes the grader passing in the sample submission into the grader.

• courseraprogramming grade local --help displays the full list of flags and options available.

upload

Allows an instructional team to upload their containers to Coursera without using a web browser. It is designed to even work in an unattended fashion (i.e. from a jenkins job). In order to make the upload command work from a Jenkins automated build machine, simply copy the ~/.coursera directory from a working machine, and install it in the jenkins home folder. Beware that the oauth2_cache file within that directory contains a refresh token for the user who authorized themselves. This refresh token should be treated as if it were a password and not shared or otherwise disclosed!

This command can also be used to customize the resources that will be allocated to your grader when it grades learner submissions. The CPU, memory limit and timeout are all customizable.

• --grader-cpu takes a value of 1 or 2, representing the number of cores the grader will have access to when grading. The default is 1.

• --grader-memory-limit takes a value of 1024 or 2048, representing the amount of memory in MB the grader will have access to when grading. The default is 1024.

• --grading-timeout takes a value between 300 and 1800, representing the amount of time the grader is allowed to run before it times out. Note this value is counted from the moment the grader starts execution and does not include the time it takes Coursera to schedule the grader. The default value is 1200.

Examples:

• courseraprogramming upload $MY_CONTAINER_IMAGE $COURSE_ID $ITEM_ID $PART_ID uploads the specified grader container image to Coursera, begins and the post-upload processing, and associates the new grader with the specified item part in a new draft. Navigate to the course authoring UI to publish the draft to make it live.

• courseraprogramming upload --help displays all available options for the upload subcommand.

publish

Allows an instructional team to publish changes made to programming assignments. Beware that all changes made to your assignment will be published, not just grader changes. Like upload, it is designed to work in an unattended fashion. Multiple items can be published at the same time using the --additional-items flag. There are multiple different error conditions that are represented by exit codes. An exit code of 1 represents a fatal error while an exit code of 2 represents a retryable error.

Examples:

• courseraprogramming publish $COURSE_ID $ITEM_ID publishes the item with item id $ITEM_ID in the course $COURSE_ID

• courseraprogramming publish $COURSE_ID $ITEM_ID_1 --additional-items $ITEM_ID_2 $ITEM_ID_3 publishes the items with ids $ITEM_ID_1, $ITEM_ID_2 and $ITEM_ID_3 in the course $COURSE_ID

Bugs / Issues / Feature Requests

Please us the github issue tracker to document any bugs or other issues you encounter while using this tool.

Supported Platforms

Note: We do not have the bandwidth to officially support this tool on windows. That said, patches to add / maintain windows support are welcome!

Developing / Contributing

We recommend developing courseraprogramming within a python virtualenv. To get your environment set up properly, do the following:

virtualenv venv
source venv/bin/activate
python setup.py develop
pip install -r test_requirements.txt

Tests

To run tests, simply run: nosetests, or tox.

Code Style

Code should conform to pep8 style requirements. To check, simply run:

pep8 courseraprogramming tests