SymfonyLive London 2016 - The Workflow Awakens

It is common having to handle statuses or product states, either on e-commerce or editorial websites. To do that, you can use the classical -manual- way, or get help from libraries covering the basis.

In this talk, we will talk about the state machine concept and definition before considering its usage looking at existing open source libraries. Finally following the Symfony way, we will study the brand-new "Workflow" component.

Transcript

1. The Workflow Awakens Tugdual Saunier
2. 2 Tugdual Saunier @tucksaun Shipping guy.
 Loves Dev, Ops and automation. London, UK Blackfire.io/SensioLabs
3. 3 History of the
 Workflow component
4. 4 Genesis
5. Winter 2013 5
7. Do we open source it? 7
8. Yes ! 8
9. In Symfony? 9
10. Ok, but Greg does the PR 10
12. As usual for @lyrixx 12
13. September 2014 13
14. Lack of time 14
15. February 2016 15
16. Let’s get back to work 16
17. 17 But was is it?
18. 18 What problems should it address?
19. 19 On an editorial website, there are several kinds of people involved. Freelancers, journalists, spellcheckers, chief editor, publication director, … An article is not published that easily. Context
20. 20 For example, an article must be validated by a journalist and a spellchecker. Otherwise, the article can not be published. Rules exist
21. 21 The component responsibili﬚ is to ensure the article properly goes by all validation steps. Welcome Workflow!
22. 22 Workflow:
 a State Machine
23. 23 States / Transitions state A state B Transition T1
24. 24 Oriented Graph A B T1 C D E T2 T3 T4 T5
25. 25 Get back to the PR
26. Read the code one more time 26
27. Being able to handle article publication process There is a serie of steps that must be fulfilled Only some users can move from one step to the other Some steps can be done at the same time Define the specs 27
28. 28 Example
29. Let’s face it,
 a state machine is not appropriate 29
30. Read some doc 30
31. Explore existing libraries 31
32. State machine: https:/ /github.com/yohang/Finite https:/ /github.com/winzou/state-machine Petrinet https:/ /github.com/florianv/petrinet https:/ /github.com/alterway/component-workflow Other https:/ /github.com/vespolina/workflow Overview 32
33. 33 Let’s move Workflow code to a “Workflow net”
34. 34 What’s this?
35. 35 This is an extension of Petri networks. It looks like state machines. But with more features. Note: Symfony Workflow component does not implement all the specs. Workflow Net
36. 36 Places / Transitions place A place B Transition T1
37. 37 Several Inputs Outputs place place Transition place place
38. 38 Tokens
39. Schrödinger's cat 39
40. 40 Marking
41. 41 Some Workflow examples
42. 42 Straight
43. 43 Round Trip
44. 44 Or
45. 45 And / Parallel
46. 46 Wait, what?
47. 47 Let’s implement
48. Diff 48
49. 49 Workflow::can()
50. 50 Workflow::can() example
51. 51 Workflow::apply()
52. 52 Workflow::apply() example
 Before
53. 53 Workflow::apply() example
 After
54. 54 Workflow::getEnabledTransitions()
55. 55 Definition class : Places
56. 56 Definition class : Transitions
57. 57 Definition class : Transitions
58. 58 Definition class : Transitions
59. 59 Definition class : Transitions
60. 60 Graphviz dumper
61. 61 The EventDispatcher has been plugged into the Workflow ! Events are dispatched each time: • a place is leſt • a transition is fired • a place is reached Events
62. 62 plus one : GuardEvent
63. 63 What about Symfony?
64. 64 It is always recommended to first draw your workflow on paper first to try it beforehand. Definition - By Hand
65. 65 Definition - YML
66. 66 Definition - YML - Supports
67. 67 Definition - YML - Places
68. 68 Definition - YML - Transitions
69. 69 What does it look like?
70. 70 The view
71. 71 The view
72. 72 The controller
73. 73 What about guard?
74. 74 What about guard?
75. 75 What about guard?
76. 76 Demo ?
77. @blackfireio #blackfireio