如何用otp的思维写出健壮高性能的erlang / elixir代码

1. otp
erlang*/*elixir
megayu
2015.05.14
1

2. • erlang
• otp
erlang supervisor gen_server ets
• beam
erlang erlang beam
• erts
erlang beam kernel
• elixir
beam
2

3. erlang func*on
3

4. func%on module
module beam
module func*on func*on module
erlang module 1 module
elixir module module
erlang erlang 1
elixir Kernel
elixir Elixir.
1
" erlang system_info
4

5. Actor
erlang actor
actor actor
actor actor
actor
5

6. erlang
erlang process func-on process
process
process process
erlang:system_info(process_limit). process
2621442
process
process mailbox process process
receive
2
"
6

7. Pid$=$spawn(Mod,$Func,$Args)
-export
Pid$=$spawn(Fun) Fun
Pid$!$Message Message Pid
Pid1!Pid2!...!Msg Msg PidX
receive&...&end
receive
7

8. receive
1. a$er 'mer
2. mailbox mailbox
3. mailbox save2queue
4. receive
save2queue
5. save2queue
mailbox 'mer 'mer
6. 'mer a$er save2queue
mailbox
8

9. pid pid
registered(process
9

10. process associa)ve+array
erlang:get().
erlang:put(a, 1).
erlang:get(a).
erlang:put(b, 1).
erlang:get(b).
erlang:put(b, erlang:get(b) + 1).
erlang:get().
erlang:erase(b).
erlang:get().
erlang:erase().
erlang:get().
10

11. erlang
11

12. catch
exit(normal)
catch
exit(Reason) Reason normal atom
12

13. signal signal
normal'exit
signal
abnormal(exit
signal
13

14. process_flag(trap_exit, true).
signal signal
{'EXIT', Pid, Reason}
mailbox
14

15. {'DOWN',Ref,process,Pid,Why}
15

16. exit(Pid, Reason) Pid
Reason exit,signal Pid
normal kill
{'EXIT', From, Reason} From
pid
normal
{'EXIT', From, normal}
kill exit'signal Pid
killed
16

17. catch Expression
exit(Reason)
catch exit(Pid, Reason)
catch
throw catch
catch
17

18. erlang
•
link monitor
•
18

19. gen_server
Client'Server Server
callback Server
gen_server module Callback module
----------------- ---------------
gen_server:start_link -----> Module:init/1
gen_server:call -----> Module:handle_call/3
gen_server:cast -----> Module:handle_cast/2
other message -----> Module:handle_info/2
exit -----> Module:terminate/2
Dynamic Code Upgrade -----> Module:code_change/3
19

20. supervisor
supervisor worker
worker gen_server gen_fsm gen_event
supervisor init
ChildSpecs = [child_spec()]
child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}
Id = term()
StartFunc = {M,F,A}
M = F = atom()
A = [term()]
Restart = permanent | transient | temporary
Shutdown = brutal_kill | int()>0 | infinity
Type = worker | supervisor
Modules = [Module] | dynamic
Module = atom()
20

21. • one_for_one
• one_for_all 1
• rest_for_one
• simple_one_for_one one_for_one
21

22. applica&on
start supervisor
erlang appname.app.src elixir mix.exs
start
22

23. otp
1. applica(on
2.
3. supervisor server
4.
5.
6.
7.
8.
9.
10.
11.
23

24. 1. catch gen_server:call
2.
3.
4.
5.
6. ETS
7.
8.
24

25. observer
shell observer:start(). observer
applica&on applica&on
ETS
25

26. erlang
•
•
erlang ETS DETS large,binaries off2heap,storage,area
ETS public
•
I/O distributed,algorithm distributed,hash,tables
•
CPU,
Core
•
mapreduce cpu2bound
erlang
26

27. Q"&"A
Thanks
27