Canvas RCE API

Canvas RCE API is a service that proxies all API requests needed for the Canvas rich content editor and sidebar. Requests are authenticated via a JWT generated by Canvas.

In the future running the Canvas RCE API service will be required for full functionality of the rich content editor in Canvas.

Running in Production

Canvas RCE API is a Node.js application. It can either be run with node directly or in a Docker container. In either case be sure to properly configure the application via environment variables and to have a web server or load balancer in front of the application to terminate TLS connections. The application does not handle https requests directly.

Node.js

The application can be run directly with Node.js by either running npm start or node app.js. It is designed to work with the current Node.js LTS (8.x) release. Be sure to run npm install --production first to install all of the package dependencies.

A Node.js process only runs on a single thread. To take full advantage of multiple CPU cores on your application server, it is reccomended that you use something to manage and balance load between node processes such as Passenger or PM2.

Docker

A Docker image is available on Docker Hub at instructure/canvas-rce-api:latest. The container will run the application behind Nginx with Passenger listening on port 80. Please refer to the documentation for the instructure/node-passenger base image for nginx and passenger configuration environment variables.

Example

docker run \
  -e ECOSYSTEM_KEY \
  -e ECOSYSTEM_SECRET \
  -e FLICKR_API_KEY \
  -e YOUTUBE_API_KEY \
  -e STATSD_PORT=8125 \
  -e STATSD_HOST=127.0.0.1 \
  instructure/canvas-rce-api

TLS

To ensure that credentials and payloads are encrypted over the wire, https should be used. https requests are not directly supported by the application. Be sure to have a TLS termination proxy in front of the application. This can be done with a load balancer such as HAProxy or Amazon ELB/ALB. It can also be done with Apache or Nginx running on the same server if you are only running a single server.

Configuration

Configuration options are set via the following environment variables:

• ECOSYSTEM_KEY: Required The encryption secret shared with Canvas.
• ECOSYSTEM_SECRET: Required The signing secret shared with Canvas.
• FLICKR_API_KEY: Required to support Flickr image search.
• YOUTUBE_API_KEY: Required for querying titles of YouTube embeds.
• NODE_ENV: This should always be set to production when running in production.
• PORT: Defaults to port 3000. This is not used when running with Docker since Node Passenger monkey patches node http to control the port each node process is listening on.
• STATSD_HOST: If you would like to collect metrics with statsd, this should be set to the host of your statsd server.
• STATSD_PORT: If you would like to collect metrics with statsd, this should be set to the port of your statsd server.

Canvas

Canvas needs to be configured with the same secrets used to encrypt and sign the JWTs used for authenticaiton. If you are running Consul to manage dynamic settings, the secrets and host should be added at the same paths as shown in the dynamic_settings.yml example below. A dynamic_settings.yml file may be used in place of managing configuration through Consul.

dynamic_settings.yml

production:
  config:
    canvas:
      canvas:
        encryption-secret: "astringthatisactually32byteslong"
        signing-secret: "astringthatisactually32byteslong"
      rich-content-service:
        app-host: "canvas-rce-api-host"

Enable Setting

To start using the new rich content editor in Canvas now, a setting needs to be enabled from the Rails console. This will not be required in the future, but it will be a good idea to enable it early to ensure everything works right before it is enabled by default.

Setting.set('rich_content_service_enabled', 'true')

Developing

Dependencies

The only dependency needed to develop canvas-rce-api is a recent LTS release of Node.js (8.x). All other dependencies are installed via npm. Alternatively if you don't want to install Node.js on your machine you can run in docker using the included docker-compose file.

Configuration

Make a copy of the example .env file. Environment variables defined in this file will be available when running the application. See the previous section for configuring Canvas to setup a local Canvas environment to test with.

cp .env.example .env

Serve the application

npm install
npm run start:dev # will automatically restart the app when you make changes

Formatting Code

This project uses prettier to automatically format source code. Code will be automatically formatted via a pre-commit hook, but it is reccomended that you configure your editor to format on save if possible.

Linting

This project uses eslint to catch non-stylistic code issues. Linting errors will cause the build to fail, so it is recommended that you configure your editor to report eslint errors.

Testing

All tests live under the top level test directory and have a *.test.js filename. Tests are written using mocha and the standard assert package. Sinon is availble for stubbing dependencies, but prefer injecting dependencies over stubbing shared bindings where possible.

License

This project is is released under the MIT license.