Life of an Erlang process

A high-level introduction to the Erlang programming language: among other topics, the talk covers Erlang processes, message passing, supervision trees, the let-it-crash approach and more.
We unfold the skeleton of an Erlang process, explaining how the functional model makes the implementation of Erlang processes straightforward. We reveal the recipe of the secret Erlang sauce which makes possible the creation of reliable, scalable systems which never go down.

Transcript

2. Life of an Erlang Process @robertoaloi
4. Let’s talk about Erlang
5. I won’t talk about the Erlang syntax.
6. Syntax is Irrelevant Programming Language is Not When you’ll look at the syntax, it’ll be too late.
7. ERLANG HAS BEEN DESIGNED TO HELP YOU WRITING SYSTEMS SCALABLE
8. ERLANG HAS BEEN DESIGNED TO HELP YOU WRITING SYSTEMS FAULT-TOLERANT
9. ERLANG HAS BEEN DESIGNED TO HELP YOU WRITING SYSTEMS HIGHLY AVAILABLE
10. ERLANG HAS BEEN DESIGNED TO HELP YOU WRITING SYSTEMS MASSIVELY CONCURRENT
11. ERLANG HAS BEEN DESIGNED TO HELP YOU WRITING SYSTEMS DISTRIBUTED
12. ERLANG HAS BEEN DESIGNED TO HELP YOU WRITING SYSTEMS SOFT REAL-TIME
13. The Erlang Rationale Users as Processes Scalable System Tons of Users Tons of Processes
14. Think Erlang Think Processes
15. Tons of them.
16. DEALING WITH TONS OF PROCESSES
17. Cheap to create Cheap to context switch OS processes out of discussion Use lightweight processes Built-in distribution to horizontally scale
18. SHARED MEMORY (or lack thereof)
19. Shared memory can leave the system in an inconsistent state after a restart or crash. Avoid it.
20. FAIL FAST
21. Faults are everywhere, you cannot prevent them. Report failure and die.
22. Processes are good. Can you show me one?
23. <0.42.0>
24. How are processes made? This is a little embarrassing, but… Ahem… I’m not sure I understand everything of it… I’ve heard rumours, still… Do you, do you mind if I ask you…
25. spawn(math, fact, [5]) math:fact(5) Pid2 Pid1
26. MESSAGE PASSING
27. Pid2 Pid1 Pid2 ! {self(), Msg} {Pid1, Msg} receive {From, start} -> … {From, stop} -> … end Send Receive
28. THE PROCESS SKELETON
29. start(Args) -> spawn(server, init, [Args]) init(Args) -> State = do_init(Args), loop(State). loop(State) ->
 receive
 {handle, Msg} -> 
 NewState = handle(Msg, State),
 loop(NewState);
 stop -> terminate(State)
 end. terminate(State) -> clean_up(State). Start Stop Initialize Terminate Loop
30. LINKS
31. PidB PidA link(PidB)
32. EXIT SIGNALS
33. PidA PidB {'EXIT', PidA, Reason} PidC {'EXIT', PidB, Reason}
34. TRAPPING EXIT SIGNALS
35. process_flag(trap_exit, true) PidA {'EXIT', PidA, Reason} PidC PidB
36. SUPERVISORS
37. PidA PidC PidB Supervisor Workers
38. erlang.org github.com/erlang/otp
    erlang-solutions.com
    www.learnyousomeerlang.org
    Erlang Programming
    Erlang and OTP in Action Official Home Page Sources Binary Packages, News, Events Best Online Tutorial Best book about basics Best book about OTP Where to Start
39. Questions? @robertoaloi Cover Image: “How computers are made” (Reddit - Ness4114)