OTP, Concurrency and Testing Strategies

An introduction to OTP, concurrency and, testing strategies for sync and async server requests in Elixir. As presented in Montreal Elixir, April 12th, 2017. Code examples are available on GH. https://github.com/xymbol/otp-examples

Transcript

1. OTP, Concurrency and Testing Strategies Adrián Mugnolo
 Montreal Elixir – April 12th, 2017
2. Why Elixir?
3. • Functional programming • Concurrent • Scalable • Fault-tolerant • Distributed
4. • Functional programming • Concurrent • Scalable • Fault-tolerant • Distributed
5. OTP
6. Open Telecom Platform
7. • Erlang interpreter and compiler • Erlang standard library • Dialyzer, a static analysis tool • Mnesia, a distributed database • ETS, and in-memory database • A debugger • An event tracer • A release-management tool
8. Complete development environment for concurrent programming
9. Concurrency primitives
10. Capture
11. • spawn • send • receive • self • make_ref
12. Servers
13. • Start as a new process • Wait for requests • Handle requests • Update state if needed • Rinse, repeat
16. GenServer
17. Capture
18. OTP behavior
21. Supervisor
22. Capture
23. “Let it crash”
24. Supervision trees
27. TDD
28. Long-running
29. No UI
30. Testing Strategies
31. Start with links
37. State
40. Stopping
43. Which server?
47. Accept options and server
50. Client first
52. Testing calls
55. Testing casts
58. Is the order of message reception guaranteed?
59. Yes, but only within one process.
60. Capture
66. Testing handlers
69. External services
70. Behaviors
73. When to use
74. • Distribute processing across cores 1:n • Coordinate work one message at a time n:1 • Keep long-running concurrent state • Need processes supervised • Want state upgraded in place
76. When not to use
77. • Simulation for objects • Code organization • Look smarter than your colleagues
78. When in doubt
79. Erlangelist
80. Thought concerns vs. runtime concerns
81. Merci
82. @xymbol