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Akka and AngularJS – Reactive Applications in Practice

Imagine how you are setting out to implement that awesome idea for a new application. In the back-end you enjoy the horizontal and vertical scalability offered by the Actor model, and its great support for building resilient systems through distribution and supervision hierarchies. In the front-end you love the declarative way of writing rich and interactive web apps that AngularJS gives you. In this presentation we bring these two together, demonstrating how little effort is needed to obtain a responsive user experience with fully consistent and persistent data storage on the server side.

See also

Akka and AngularJS – Reactive Applications in Practice

  1. 1. Akka and AngularJS Reactive Applications in Practice Dr. Roland Kuhn Akka Tech Lead @rolandkuhn
  2. 2. The Four Reactive Traits Reactive Applications 2
  3. 3. Akka ! A fully Reactive toolkit on the JVM
  4. 4. The Actor Model • fully message-driven: an Actor can react by • sending messages to other Actors • creating Actors • denominating behavior for the next message • Actors are effectively single-threaded • failures are contained and escalated within the supervisor hierarchy • scaling up & out through location transparency 4
  5. 5. Persistence Model: Event Sourcing • based on storing change instead of updating state • persistent Actors generate events: • historic facts that do not change thereafter • storage is append-only log • current Actor state is updated by consuming events • Actor can revisit the past by replaying events • events contain more business information than current state snapshot 5
  6. 6. Command Query Responsibility Segregation 6 Events Client write-! side read-! side Command Reply Query Reply
  7. 7. Command Query Responsibility Segregation • persistent Actors on write-side generate events • read-side independently consumes event streams • read model is fully decoupled from write model • queries are served from optimal storage: • SQL store • graph database • in-memory live view • new read model can be generated on demand 7
  8. 8. Spray / Akka HTTP ! An Actor-Based Web Toolkit
  9. 9. Web-Server made Simple • HTTP requests and responses are Actor messages • powerful routing DSL turns Actor into Web-Server • not a web framework: • just expose Actors as web endpoints • nicely suited for RESTful APIs 9
  10. 10. Important Disclaimer • I know a lot about Akka, but … • I am not a web developer 10
  11. 11. Gabbler: The Write-Side 11 Log Router Gabbler Replayer Journal Input POST 201
  12. 12. Gabbler: The Read-Side 12 Log Router Gabbler Replayer Journal Input GET Replay 200
  13. 13. Gabbler: The Whole Thing 13 Log Router Gabbler Replayer Journal Input
  14. 14. Further Information • Code at • currently a pull request • See also 14
  15. 15. ©Typesafe 2014 – All Rights Reserved