Rubrics is a project which adds native rubrics support to Sakai.
This was developed as part of the Apereo FARM - Sakai Native Rubrics initiative.
This was a collaborative effort between Longsight, Inc. and Unicon, Inc. Longsight worked on the community requirements gathering and initial designs with New York University and others, and then Unicon developed the initial release on behalf of and supported by the Uniformed Services University (USU) as part of the first development phase.
The initial designs focused primarily on rubrics support within Gradebook NG, however, after some rounds of designs and prototypes put forth by Unicon and driven by USU requirements shifted the focus of the first phase of development on the core Rubrics service and Assignment Tool integration.
The framework is in place for integration into Gradebook and potentially other tools such as Forums and Samigo.
The technology proposal put forth by Unicon and reviewed by Longsight significantly departed from traditional Sakai design patterns. The focus of this solution was to develop a fully encapsulated, lightweight and reusable solution based on a micro-service architectural pattern with client view components so that it can be directly leveraged within multiple tools with minimal development required for each tool integration.
The Rubrics service for Sakai is built as a separate service (not added to GradebookNG or any other existing tool) in order to be able to work with any Sakai configuration and not be tightly coupled to any other specific tools (for example where legacy Gradebook is used or no Gradebook is used at all). Tools should interface with Rubrics only through either the client view layer components which encapsulate the necessary web services calls to deliver various use cases, or sparingly via Restful web service API access (directly or via the provided Service Client API).
The sole focus of the Rubrics service should be on supporting APIs and a set of views to deliver the functional use cases for rubrics:
- Managing rubrics (create, edit, delete, copy, sharing/access control)
- Searching for, selecting and associating rubrics with external entities (gradebook entries, assignments, short answer assessment questions, forums, etc.)
- Delivery of the rubric for evaluation
- Delivery of the rubric report/outcome for review
The rubrics service centralizes all rubrics persistence and provides a set of views to be embedded and used by all tools within Sakai.
The Rubrics service provides a set of APIs to persist the mapping of external tool items so that every integrating tool does not have to modify their persistence model and maintain those relationships. The Tools may store certain rubrics resource identifiers internally, but that is not required, as long as the tool can produce unique tool item association IDs within its own namespace that it can use for lookup.
The responsibility for establishing user authentication and determining roles and permissions authorization is left to the core of Sakai and each tool to pass along the necessary site context and user information including roles via the JSON Web Token (JWT) standard.
Rubrics are scoped to a context, which is site based, but there is flexibility to allow for other contexts like personal buckets to be added as enhancements. This means that rubrics are created within the context of a site and visible only within a site.
There is currently a global public sharing capability which allows for a temporary or permanent share and copy in another site by the same instructor or another instructor via the public list. Targeted sharing to specific sites or users is not yet supported.
There are four new permissions added to the Sakai Realms to be mapped appropriately:
- rbcs.editor - Authorized to create, edit and share rubrics.
- rbcs.associator - Authorized to associate rubrics with integrating tool items.
- rbcs.evaluator - Authorized to use a rubric and submit an evaluation with comments based on the rubric.
- rbcs.evaluee - Target of a rubric evaluation, only able to view rubrics and evaluations for their tool item submissions.
Typically an instructor will have all four permissions granted for a site, and students will only have evaluee. Those details are left to the Sakai Administrators to set up the appropriate mappings. Note that support for peer review rubrics has not yet been implemented.
Use of JWT supports the decoupling goal which allows Rubrics to optionally run in a separate JVM.
Example of JWT required payload with standard and custom claims for Rubrics.
{
"iss": "sakai",
"aud": "rubrics",
"sub": "cda94cae-83b8-4d44-9df7-0c0fe9269500",
"toolId": "sakai.assignment",
"roles": [
"rbcs.editor",
"rbcs.associator",
"rbcs.evaluator",
"rbcs.evaluee"
],
"contextId": "50100776-7540-4d70-8840-9579d09a5408",
"contextType": "site",
"sessionId": "0d00c1f0-c5b6-4b1b-b51b-2c13595554ff",
"exp": 1486169472,
"iat": 1486155072
}
sub is the principal/user ID this token is representing.
The Rubrics Service Client API provides a method to generate a JWT with only a tool ID, and it gathers all of the other information from Sakai.
Tools should leverage the Rubrics Service Client API to easily generate JWTs to communicate with Rubrics REST services directly, and also use the client API methods to simplify integration for those few places where embedding a rubrics web component does not fulfill the need.
Rubrics is developed using modern technologies to leverage the emerging next generation of web development:
- Java (Java 8+)
- JavaScript, HTML5, CSS
- JSON Web Tokens (JWT) see also RFC 7519
The services module is intended to be completely standalone and only communicate with core Sakai via Sakai Web Services. As a result, this decouples the web application and allows it to leverage unique versions of Spring and libraries like Spring Boot and Spring Data REST without impacting the whole of Sakai.
Web Components and Polymer were selected to develop fully encapsulated reusable components which can essentially be dropped into any tool markup with only a thin JavaScript bridge library to support it.
The Tool and API/Impl modules are more traditional Sakai backend technologies using Spring and Wicket, however, the API/Impl does leverage Spring HATEOAS and its Traverson client to navigate the Level 3 Hypermedia Restful APIs provided.
The architecture for Rubrics provides a step towards decoupling Sakai tools from the core/kernel, which in theory will allow for a more modular deployment architecture where tools can be deployed and scaled independently from the core/kernel to address load and performance needs.
The Rubrics Services Spring Boot application needs a bit more work to support the separation, but it will be able to be run in a separate JVM or JVM cluster, ideally as a dedicated Docker container.
Splitting out tools into separate micro-services able to be packaged as Docker containers will allow for the full power of containerization, auto-scaling and clustering technologies such as Docker Swarm or Kubernetes to eventually be leveraged by Sakai as an evolutionary step beyond the current monolith Sakai Docker support.
The Rubrics module consists of three key artifacts:
Contained in the 3 sub-modules:
- api - Contains the Rubrics Service Client API and DTO model
- impl - Contains the Rubrics Service Client implementation
- pack - Standard Sakai Component package module
Provides Rubrics Service client code and simple data transfer model for use by tools.
Contained in the sub-module: tool
Provides the Rubrics Management Tool for creating, editing and sharing rubrics within a site. This is a very lightweight tool which itself is an example of the view component integration. The actual management capabilities are provided by the web components and rubrics web services directly, this tool is just a shell for embedding the rubric manager component.
Contained in the sub-module: services
Provides the core rubrics Level 3 Hypermedia Restful APIs, model persistence and embeddable web components.
The Rubrics service Spring Boot has its own application.properties with much of its default configuration. Spring Boot is highly configurable with common application properties.
In order to manage all configuration within sakai.properties, add the following to the Tomcat startup environment (via JAVA_OPTS):
-Dspring.config.location=/path/to/sakai.properties
This loads sakai.properties into the Rubrics services layer and allows for any properties in rubrics/services/src/main/resources/application.properties to be overridden. Sakai properties are ignored, only Spring Boot common application properties and rubrics.* specific properties are used.
The following properties should be overridden:
spring.datasource.url=jdbc:mysql://server/sakaidb
spring.datasource.username=sakai
spring.datasource.password=sakai
rubrics.integration.sakai-rest-url=http://sakai-core:8080/sakai-ws/rest/
rubrics.integration.token-secret=<Unique secret to support JWT signing>
Rubrics can be loaded into the same database as Sakai core, or a separate database. The spring.datasource settings above must be configured either way.
NOTE: The Sakai web services requires access, so the configuration should allow at least localhost to access
webservices.allowlogin=true
webservices.allow=localhost
Rubrics uses Spring Boot type-safe configuration to load a very complex configuration set, including defaults for the rubrics data model for the instance, which supports multiple languages.