Game Servers in OTP

Given at ElixirConf 2014

1. Game Servers in OTP
2. @msch featurebranch.com
7. Architecture big-picture The Table-FSM Life of an in-game event Real world concerns BoldPoker <3 Elixir Lessons Learned & QA
8. HA keepalived haproxy active Erlang active Erlang standby Erlang standby PostgreSQL haproxy standby
9. Erlang active
10. OTP Apps :cardgame :storage :network :gameserver
11. :cardgame OTP APP {Table,9} {Table,8} {Table,7} {Table,6}
12. :network OTP APP WebSocket :cowboy Flash (TCP) :ranch
13. :storage OTP APP PSQLDBWorker TableIdSequence
14. :gameserver OTP APP {Player,1} {Player,2} {Player,3}
15. Architecture big-picture The Table-FSM Life of an in-game event Real world concerns BoldPoker <3 Elixir Lessons Learned & QA
17. DealCards Knocking DealCards Play Result idle playing
18. [ {DealCards, [cards_to_deal, :private]}, {Knocking, [5000]}, {DealCards, [cards_to_deal, :private]}, {Negotiation, []}, {Play, [contra_enabled: true]}, {Play, []}, {Play, []}, … {Play, []}, {Play, []}, {Result, []} ]
19. gen_fsm:send_event/2 -----> Module:StateName/2 gen_fsm:send_event/2 -----> Table.playing/2 {:next_state, next_state_name, new_state_data} ! {:stop, reason, new_state_data}
20. DealCards Knocking DealCards Play Result idle playing
21. {:next_stage, new_stage_data, new_state_data} ! {:end_game, new_stage_data, new_state_data} ! Table.broadcast_event {:next_state, next_state_name, new_state_data} ! {:stop, reason, new_state_data} ! GenServer.reply Table.playing/2 -----> DealCards.playing/3
22. DealCards Knocking DealCards Play Result idle playing
23. Knocking DealCards Play Result idle playing
24. DealCards Play Result idle playing
25. Play Result idle playing {:game_event, …}
26. Play Result idle playing {:game_event, …}
27. Architecture big-picture The Table-FSM Life of an in-game event Real world concerns BoldPoker <3 Elixir Lessons Learned & QA
28. P1 P2 P3 P4 {Table,9} {Player,1}
29. P1 P2 P3 P4 {Table,9} {Player,1} Ports
30. P1 P2 P3 P4 {Table,9} {Player,1}
31. P1 P2 P3 P4 {Table,9} {Player,1} {:game_event, :must_play_card}
32. P1 {Table,9} {Player,1} {:game_event, …}
33. P1 {Table,9} {Player,1} { "type": "mustPlayCard" } {:game_event, :must_play_card} ProtocolJSON.write/1
34. P1 {Table,9} {Player,1}
35. P1 {Table,9} {Player,1} { "type": "playACard", "card": "XH" } {:game_event, {:play_card,{:ten,:hearts}} ProtocolJSON.parse/1
36. P1 {Table,9} {Player,1} {:game_event, …}
37. Architecture big-picture The Table-FSM Life of an in-game event Real world concerns BoldPoker <3 Elixir Lessons Learned & QA
38. P1 P2 P3 P4 {Table,9} {Player,1}
39. haproxy active Erlang active Erlang standby Erlang standby
40. haproxy active Erlang standby Erlang active Erlang standby
41. :rpc.multicall(GameServer, switch_active, [node()])
42. P1 P2 P3 P4 {Table,9} P5 P6 P7 old
43. P1 P2 P3 P4 {Table,9} P5 P6 P7 old
44. P1 P2 P3 P4 {Table,9} old
45. P1 P2 P3 P4 {Table,9} old new {TableMigrator,9}
46. P1 P2 P3 P4 {Table,9} old new {TableMigrator,9}
47. P1 P2 P3 P4 {Table,9} P5 P6 P7 old new {TableMigrator,9}
48. P1 P2 P3 P4 {Table,9} P5 P6 P7 old new {TableMigrator,9}
49. P1 P2 P3 P4 {Table,9} P5 P6 P7 old new {TableMigrator,9}
50. P1 P2 P3 P4 {Table,9} P5 P6 P7 old new {TableMigrator,9}
51. P1 P2 P3 P4 {Table,9} P5 P6 P7 old new ConnectionProxy {TableMigrator,9}
52. P1 P2 P3 P4 {Table,9} P5 P6 P7 old new {TableMigrator,9}
53. P1 P2 P3 P4 {Table,9} old new {TableMigrator,9}
55. DealCards Knocking DealCards Play Result idle playing
56. P1 P2 P3 P4 old new {TableMigrator,9} portable_state
57. P1 2 3 4 old new { portable_state portable_state %{table_id:  9,      player_ids:  [1,2,3,4],      positions:  %{1  =>  3,                                2  =>  0,                                3  =>  1,                                4  =>  2},      modifications:  [:short_hand],      last_game_id:  123   }
58. P1 P2 P3 P4 old new {TableMigrator,9}
59. old new {TableMigrator,9}
60. old new {TableMigrator,9}
63. old new {TableMigrator,9}
64. old new {TableMigrator,9} P1
65. old new {TableMigrator,9} P2 P3 P4 P1
66. old new {TableMigrator,9} P2 P3 P4 P1 portable_state
67. old new P2 P3 P4 P1 {Table,9}
69. P2 P3 P4 P1 {Table,9}
70. Architecture big-picture The Table-FSM Life of an in-game event Real world concerns BoldPoker <3 Elixir Lessons Learned & QA
71. All-in! Elixir Rewrite
72. Why? Extensibility goals stdlib mix ExUnit
73. :gen_fsm :ets GenServer Supervisor alias :ets, as: ETS
74. proper Tests send_events(ClientDeviceIDs, ClientIP) -> ?FORALL(Event, event(), ?FORALL(Data, event_data(Event), ...
75. parse_transform ?
76. Architecture big-picture The Table-FSM Life of an in-game event Moving tables across servers BoldPoker <3 Elixir Lessons Learned & QA
77. Perform en/decoding at the system border P1 { "type": "playACard", "card": "XH" } {:game_event, {:play_card,{:ten,:hearts}} ProtocolJSON.parse/1 WS
78. Create your own behaviours for fun better reusability and profit easier testing {:next_stage, new_stage_data, new_state_data} {:end_game, new_stage_data, new_state_data}
79. Distributed Erlang makes hard things easy ConnectionProxy
80. DB failure? We got all data already, so finish the game, then just store result on disk
81. Thank you! @msch featurebranch.com