This app serves as the realtime component of canvas. It runs a ShareDB server, which provides operational transformation for operations on canvases.
See app.json for details about environment variables for the following dependencies.
- PostgreSQL: The realtime server needs to read from and write to the API's PostgreSQL database instance in order to read and write operations and canvas document states.
- Redis (1): The realtime server needs a connection to the API's Redis instance so that it can trigger jobs based on certain incoming operations.
- Redis (2): ShareDB uses Redis for caching of operations. This can be the same Redis instance as the API Redis instance, if need be.
Running on Heroku
After deploying the Canvas API, this app can be deployed using the Heroku button above. After the app is created, attach the API's PostgreSQL and Redis addons:
$ heroku addons:attach $API_DATABASE_ADDON_NAME --as DATABASE $ heroku addons:attach $API_REDIS_ADDON_NAME --as API_REDIS