Plugins can be created by exposing an importable class that inherits from otter.plugins.AbstractOtterPlugin. This class defines the base implementations of the plugin event methods and sets up the other information needed to run the plugin.
When instantiated, plugins will receive three arguments: submission_path, the absolute path to the submission being executed, submission_metadata, the information about the submission as read in from submission_metadata.json, and plugin_config, the parsed configurations from the user-specified list of plugins in the plugins key of otter_config.json. The default implementation of __init__, which should have the signature shown below, sets these two values to the instance variables self.submission_metadata and self.plugin_config, respectively. Note that some events are executed in contexts in which some or all of these variables are unavailable, and so these events should not rely on the use of these instance variables. In cases in which these are unavailable, they will be set for the falsey version of their type, e.g. {} for self.submission_metadata.
Plugins currently support five events. Most events are expected to modify the state of the autograder and should not return anything, unless otherwise noted. Any plugins not supported should raise a otter.plugins.PluginEventNotSupportedException, as the default implementations in AbstractOtterPlugin do. Note that all methods should have the signatures described below.
The during_assign method will be called when Otter Assign is run. It will receive the otter.assign.assignment.Assignment instance with configurations for this assignment. The plugin is run after output directories are written.
The during_generate method will be called when Otter Generate is run. It will receive the parsed dictionary of configurations from otter_config.json as its argument. Any changes made to the configurations will be written to the otter_config.json that will be stored in the configuration zip file generated by Otter Generate.
The from_notebook method will be called when a student makes a call to otter.Notebook.run_plugin with the plugin name. Any additional args and kwargs passed to Notebook.run_plugin will be passed to the plugin mehod. This method should not return anything but can modify state or provide feedback to students. Note that because this plugin is not run in the grading environment, it will not be passed the submission path, submission metadata, or a plugin config. All information needed to run this plugin event must be gathered from the arguments passed to it.
The notebook_export method will be called when a student makes a call to otter.Notebook.add_plugin_files witht he plugin name. Any additional args and kwargs passed to Notebook.add_plugin_files will be passed to the plugin mehod. This method should return a list of strings that correspond to file paths that should be included in the zip file generated by otter.Notebook.export when it is run. The Notebook instance tracks these files in a list. Note that because this plugin is not run in the grading environment, it will not be passed the submission path, submission metadata, or a plugin config. All information needed to run this plugin event must be gathered from the arguments passed to it.
The before_grading method will be called before grading occurs, just after the plugins are instantiated, and will be passed the parsed dictionary of configurations from otter_config.json, including the default configurations stored in otter.generate.constants.DEFAULT_OPTIONS. Any changes made to the options will be used during grading.
The before_execution method will be called before execution occurs and will be passed the student's submission. If the submission is a notebook, the object passed will be a nbformat.NotebookNode from the parsed JSON. If the submission is a script, the objet passed will be a string containing the file text. This method should return a properly-formatted NotebookNode or string that will be executed in place of the student's original submission.
The after_execution method will be called after the student's submission is executed but before the results object is created. It will be passed the global environment resulting from the execution of the student's code. Any changes made to the global environment will be reflected in the tests that are run after execution (meaning any that do not have a call to otter.Notebook.check to run them).
The after_grading method will be called after grading has occurred (meaning all tests have been run and the results object has been created). It will be passed the otter.test_files.GradingResults object that contains the results of the student's submission against the tests. Any changes made to this object will be reflected in the results returned by the autograder. For more information about this object, see Grading Results.
The generate_report method will be called after results have been written. It receives no arguments but should return a value. The return value of this method should be a string that will be printed to stdout by Otter as part of the grading report.
.. autoclass:: otter.plugins.AbstractOtterPlugin
:members: