Woot for Lift

Presentation at Scala eXchange, London, 3 December 2013.
With @jonoabroad

Transcript

1. \o/ WOOT
   for Lift Richard Dallaway @d6y Jono Ferguson @jonoabroad
2. Richard Dallaway @d6y
3. Collaborative Editing
4. Don’t Do This A B C A B C Site A Site B 1 2 3 1 2 3
5. Don’t Do This A B C A B C Site A Site B 1 2 3 1 2 3 A x B C 1 2 3 4 insert x @ 2
6. Don’t Do This A B C A B C Site A Site B 1 2 3 1 2 3 A x B C 1 2 3 4 insert x @ 2 A B 1 2 delete 3
7. Don’t Do This A B C A B C Site A Site B 1 2 3 1 2 3 A x B C 1 2 3 4 insert x @ 2 A B 1 2 delete 3 A x B
8. Don’t Do This A B C A B C Site A Site B 1 2 3 1 2 3 A x B C 1 2 3 4 insert x @ 2 A B 1 2 delete 3 A x B A x C
9. What do we want? ‣Intention Preservation
   ‣Causal Consistency
   ‣Convergence When do we want it? Eventually
10. The WOOT Algorithm
11. WOOT A B C A B C Site A Site B 1 2 3 1 2 3
12. WOOT A B C A B C Site A Site B 1 2 3 1 2 3 1 2 3 4 A x B C A ≺ x ≺ B
13. WOOT A B C A B C Site A Site B 1 2 3 1 2 3 1 2 3 4 A x B C A ≺ x ≺ B 1 2 A B delete C
14. WOOT A B C A B C Site A Site B 1 2 3 1 2 3 1 2 3 4 A x B C A ≺ x ≺ B 1 2 A B delete C A x B
15. WOOT A B C A B C Site A Site B 1 2 3 1 2 3 1 2 3 4 A x B C A ≺ x ≺ B 1 2 A B delete C A x B A x B
16. WChar ID Prev Next Alpha Visible?
17. WChar ID Prev Next Alpha Visible? Site Clock
18. WChar ID Prev Next Alpha Visible? Site Clock ID ID
19. WOOT Algorithm Local Integration Remote Integration
20. WOOT Algorithm (WString, Char, Pos) => 
 (WString, WChar) Local Integration Remote Integration
21. WOOT Algorithm (WString, Char, Pos) => 
 (WString, WChar) Local Integration (WString, WChar) => WString Remote Integration
22. WOOT Algorithm a b c d a b c d a b c d a b c x d a c d a b y c d
23. WOOT Algorithm a b c d a b c d a b c d a b c x d a c d a b y c d a b c d
24. WOOT Algorithm a b c d a b c d a b c d a b c x d a c d a b y c d a b c d x
25. WOOT Algorithm a b c d a b c d a b c d a b c x d a c d a b y c d a b c d x ／
26. WOOT Algorithm a b c d a b c d a b c d a b c x d a c d a b y c d a b c d x y ／
27. Example using Ace
28. Scala, JavaScript, Lift WOOT Local WOOT Model
29. Scala, JavaScript, Lift WOOT x Local WOOT Model
30. Scala, JavaScript, Lift WOOT x Local WOOT Model A ≺ x ≺ B
31. Scala, JavaScript, Lift WOOT WOOT WOOT x Local WOOT Model A ≺ x ≺ B
32. Scala, JavaScript, Lift WOOT WOOT WOOT x Local WOOT Model A ≺ x ≺ B
33. Scala, JavaScript, Lift WOOT WOOT WOOT x x x Local WOOT Model A ≺ x ≺ B
34. Fork It
    bitbucket.org/d6y/woot
35. Fork It
    bitbucket.org/d6y/woot $ git clone https://d6y@bitbucket.org/d6y/woot.git $ ./sbt > container:start
36. Fork It
    bitbucket.org/d6y/woot $ git clone https://d6y@bitbucket.org/d6y/woot.git $ ./sbt > container:start
37. JavaScript jQuery(document).ready(function() { wootServer.init({doc:1}).then(messageHandler); });
38. JavaScript jQuery(document).ready(function() { wootServer.init({doc:1}).then(messageHandler); }); <script data-lift="WootServices"> var wootServer = { init: function(config) { return $.Deferred().promise(); }, send: function(wchar) {} }; </script>
39. JavaScript jQuery(document).ready(function() { wootServer.init({doc:1}).then(messageHandler); }); <script data-lift="WootServices"> var wootServer = { init: function(config) { return $.Deferred().promise(); }, send: function(wchar) {} }; </script>
40. Scala def services = List[RoundTripInfo]( "send" -> receive _, "init" -> init _)
41. Scala def services = List[RoundTripInfo]( "send" -> receive _, "init" -> init _) def init(config: JValue) : Stream[JValue] = { ! 
 ! }
42. Scala def services = List[RoundTripInfo]( "send" -> receive _, "init" -> init _) def init(config: JValue) : Stream[JValue] = { ! 
 ! } val doc = toJson(wootModel) val q = LinkedBlockingQueue[JValue]() doc #:: Stream.continually(q.take())
43. Pros ‣No vector clocks ‣Simple
 LoC Scala JavaScript Model 100 200 Glue 100 100
44. Cons ‣Bulk operations ‣Space
 ‣No GC

45. You Have Options OT Many options (since 1998) •Wave •Google Docs •Etherpad Post-OT Tombstones Tombstones WOOT 2005 RGA 2011 CT 2010 Treedoc 2007 Logoot 2009 LSEQ 2013 ×
46. References Oster et al (2006) Data Consistency for P2P Collaborative Editing http://www.loria.fr/~oster/pmwiki/pub/papers/OsterCSCW06.pdf Ahmed-Nacer et al (2011) Evaluating CRDTs for Real-time Document Editing http://hal.archives-ouvertes.fr/docs/00/62/95/03/PDF/doce63-ahmednacer.pdf Nédelec, Molli, Mostefaoui & Desmontils (2013)
 LSEQ: an Adaptive Structure for Sequences in Distributed Collaborative Editing http://dl.acm.org/citation.cfm?id=2494278
47. Summary ‣WOOT pretty neat ‣Lift is pretty neat ‣Put effort into the editor
 ‣Fun area, go explore

48. Thank
    you Richard Dallaway Jono Ferguson @d6y @jonoabroad bitbucket.org/d6y/woot