User Tracker

Library for displaying current (logged in) users of your application.

Designed so as to be non-blocking on writes and reads, and to perform as few database operations as possible in the background. (i.e., it's supposed to be cheap to use!)

Usage

Persistence

Persistence allows your logged in user data to be propagated across a set of servers.

Either implement the Persistence layer yourself or use the provided DynamoDBPersistence with DynamoDB.

val persistence = DynamoDBPersistence(
  client = new AmazonDynamoDBAsyncClient(),
  tableName = "application_users"
)

If using DynamoDBPersistence make sure to start the GC cycle:

DynamoDBPersistence.startGarbageCollection(persistence, frequency = 5 minutes)

User Tracking

Create a single instance of UserTracker at application start up:

val userTracker = new UserTracker(
  persistence
)

Trigger the scheduled updates to the persistence layer at start up:

UserTracker.startPersistence(userTracker)

Tell the user tracker when you see a user:

userTracker.recordSeenNow(UserId("robert"))

Ask the user tracker for the currently active users:

val users = userTracker.currentlyActive

License

Copyright Guardian News & Media. Licensed under Apache 2.0.