-
Notifications
You must be signed in to change notification settings - Fork 3.9k
/
supervisor2.erl
1566 lines (1418 loc) · 55.6 KB
/
supervisor2.erl
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
%% This file is a copy of supervisor.erl from the R16B Erlang/OTP
%% distribution, with the following modifications:
%%
%% 1) the module name is supervisor2
%%
%% 2) a find_child/2 utility function has been added
%%
%% 3) Added an 'intrinsic' restart type. Like the transient type, this
%% type means the child should only be restarted if the child exits
%% abnormally. Unlike the transient type, if the child exits
%% normally, the supervisor itself also exits normally. If the
%% child is a supervisor and it exits normally (i.e. with reason of
%% 'shutdown') then the child's parent also exits normally.
%%
%% 4) child specifications can contain, as the restart type, a tuple
%% {permanent, Delay} | {transient, Delay} | {intrinsic, Delay}
%% where Delay >= 0 (see point (4) below for intrinsic). The delay,
%% in seconds, indicates what should happen if a child, upon being
%% restarted, exceeds the MaxT and MaxR parameters. Thus, if a
%% child exits, it is restarted as normal. If it exits sufficiently
%% quickly and often to exceed the boundaries set by the MaxT and
%% MaxR parameters, and a Delay is specified, then rather than
%% stopping the supervisor, the supervisor instead continues and
%% tries to start up the child again, Delay seconds later.
%%
%% Note that if a child is delay-restarted this will reset the
%% count of restarts towrds MaxR and MaxT. This matters if MaxT >
%% Delay, since otherwise we would fail to restart after the delay.
%%
%% Sometimes, you may wish for a transient or intrinsic child to
%% exit abnormally so that it gets restarted, but still log
%% nothing. gen_server will log any exit reason other than
%% 'normal', 'shutdown' or {'shutdown', _}. Thus the exit reason of
%% {'shutdown', 'restart'} is interpreted to mean you wish the
%% child to be restarted according to the delay parameters, but
%% gen_server will not log the error. Thus from gen_server's
%% perspective it's a normal exit, whilst from supervisor's
%% perspective, it's an abnormal exit.
%%
%% 5) normal, and {shutdown, _} exit reasons are all treated the same
%% (i.e. are regarded as normal exits)
%%
%% All modifications are (C) 2010-2013 GoPivotal, Inc.
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(supervisor2).
-behaviour(gen_server).
%% External exports
-export([start_link/2, start_link/3,
start_child/2, restart_child/2,
delete_child/2, terminate_child/2,
which_children/1, count_children/1,
find_child/2, check_childspecs/1]).
%% Internal exports
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-export([try_again_restart/3]).
%%--------------------------------------------------------------------------
-ifdef(use_specs).
-export_type([child_spec/0, startchild_ret/0, strategy/0, sup_name/0]).
-endif.
%%--------------------------------------------------------------------------
-ifdef(use_specs).
-type child() :: 'undefined' | pid().
-type child_id() :: term().
-type mfargs() :: {M :: module(), F :: atom(), A :: [term()] | undefined}.
-type modules() :: [module()] | 'dynamic'.
-type delay() :: non_neg_integer().
-type restart() :: 'permanent' | 'transient' | 'temporary' | 'intrinsic' | {'permanent', delay()} | {'transient', delay()} | {'intrinsic', delay()}.
-type shutdown() :: 'brutal_kill' | timeout().
-type worker() :: 'worker' | 'supervisor'.
-type sup_name() :: {'local', Name :: atom()} | {'global', Name :: atom()}.
-type sup_ref() :: (Name :: atom())
| {Name :: atom(), Node :: node()}
| {'global', Name :: atom()}
| pid().
-type child_spec() :: {Id :: child_id(),
StartFunc :: mfargs(),
Restart :: restart(),
Shutdown :: shutdown(),
Type :: worker(),
Modules :: modules()}.
-type strategy() :: 'one_for_all' | 'one_for_one'
| 'rest_for_one' | 'simple_one_for_one'.
-endif.
%%--------------------------------------------------------------------------
-ifdef(use_specs).
-record(child, {% pid is undefined when child is not running
pid = undefined :: child() | {restarting,pid()} | [pid()],
name :: child_id(),
mfargs :: mfargs(),
restart_type :: restart(),
shutdown :: shutdown(),
child_type :: worker(),
modules = [] :: modules()}).
-type child_rec() :: #child{}.
-else.
-record(child, {
pid = undefined,
name,
mfargs,
restart_type,
shutdown,
child_type,
modules = []}).
-endif.
-define(DICT, dict).
-define(SETS, sets).
-define(SET, set).
-ifdef(use_specs).
-record(state, {name,
strategy :: strategy(),
children = [] :: [child_rec()],
dynamics :: ?DICT:?DICT() | ?SET:?SET(),
intensity :: non_neg_integer(),
period :: pos_integer(),
restarts = [],
module,
args}).
-type state() :: #state{}.
-else.
-record(state, {name,
strategy,
children = [],
dynamics,
intensity,
period,
restarts = [],
module,
args}).
-endif.
-define(is_simple(State), State#state.strategy =:= simple_one_for_one).
-define(is_permanent(R), ((R =:= permanent) orelse
(is_tuple(R) andalso
tuple_size(R) == 2 andalso
element(1, R) =:= permanent))).
-define(is_explicit_restart(R),
R == {shutdown, restart}).
-ifdef(use_specs).
-callback init(Args :: term()) ->
{ok, {{RestartStrategy :: strategy(),
MaxR :: non_neg_integer(),
MaxT :: non_neg_integer()},
[ChildSpec :: child_spec()]}}
| ignore.
-else.
-export([behaviour_info/1]).
behaviour_info(callbacks) ->
[{init,1}];
behaviour_info(_Other) ->
undefined.
-endif.
-define(restarting(_Pid_), {restarting,_Pid_}).
%%% ---------------------------------------------------
%%% This is a general process supervisor built upon gen_server.erl.
%%% Servers/processes should/could also be built using gen_server.erl.
%%% SupName = {local, atom()} | {global, atom()}.
%%% ---------------------------------------------------
-ifdef(use_specs).
-type startlink_err() :: {'already_started', pid()}
| {'shutdown', term()}
| term().
-type startlink_ret() :: {'ok', pid()} | 'ignore' | {'error', startlink_err()}.
-spec start_link(Module, Args) -> startlink_ret() when
Module :: module(),
Args :: term().
-endif.
start_link(Mod, Args) ->
gen_server:start_link(?MODULE, {self, Mod, Args}, []).
-ifdef(use_specs).
-spec start_link(SupName, Module, Args) -> startlink_ret() when
SupName :: sup_name(),
Module :: module(),
Args :: term().
-endif.
start_link(SupName, Mod, Args) ->
gen_server:start_link(SupName, ?MODULE, {SupName, Mod, Args}, []).
%%% ---------------------------------------------------
%%% Interface functions.
%%% ---------------------------------------------------
-ifdef(use_specs).
-type startchild_err() :: 'already_present'
| {'already_started', Child :: child()} | term().
-type startchild_ret() :: {'ok', Child :: child()}
| {'ok', Child :: child(), Info :: term()}
| {'error', startchild_err()}.
-spec start_child(SupRef, ChildSpec) -> startchild_ret() when
SupRef :: sup_ref(),
ChildSpec :: child_spec() | (List :: [term()]).
-endif.
start_child(Supervisor, ChildSpec) ->
call(Supervisor, {start_child, ChildSpec}).
-ifdef(use_specs).
-spec restart_child(SupRef, Id) -> Result when
SupRef :: sup_ref(),
Id :: child_id(),
Result :: {'ok', Child :: child()}
| {'ok', Child :: child(), Info :: term()}
| {'error', Error},
Error :: 'running' | 'restarting' | 'not_found' | 'simple_one_for_one' |
term().
-endif.
restart_child(Supervisor, Name) ->
call(Supervisor, {restart_child, Name}).
-ifdef(use_specs).
-spec delete_child(SupRef, Id) -> Result when
SupRef :: sup_ref(),
Id :: child_id(),
Result :: 'ok' | {'error', Error},
Error :: 'running' | 'restarting' | 'not_found' | 'simple_one_for_one'.
-endif.
delete_child(Supervisor, Name) ->
call(Supervisor, {delete_child, Name}).
%%-----------------------------------------------------------------
%% Func: terminate_child/2
%% Returns: ok | {error, Reason}
%% Note that the child is *always* terminated in some
%% way (maybe killed).
%%-----------------------------------------------------------------
-ifdef(use_specs).
-spec terminate_child(SupRef, Id) -> Result when
SupRef :: sup_ref(),
Id :: pid() | child_id(),
Result :: 'ok' | {'error', Error},
Error :: 'not_found' | 'simple_one_for_one'.
-endif.
terminate_child(Supervisor, Name) ->
call(Supervisor, {terminate_child, Name}).
-ifdef(use_specs).
-spec which_children(SupRef) -> [{Id,Child,Type,Modules}] when
SupRef :: sup_ref(),
Id :: child_id() | undefined,
Child :: child() | 'restarting',
Type :: worker(),
Modules :: modules().
-endif.
which_children(Supervisor) ->
call(Supervisor, which_children).
-ifdef(use_specs).
-spec count_children(SupRef) -> PropListOfCounts when
SupRef :: sup_ref(),
PropListOfCounts :: [Count],
Count :: {specs, ChildSpecCount :: non_neg_integer()}
| {active, ActiveProcessCount :: non_neg_integer()}
| {supervisors, ChildSupervisorCount :: non_neg_integer()}
|{workers, ChildWorkerCount :: non_neg_integer()}.
-endif.
count_children(Supervisor) ->
call(Supervisor, count_children).
-ifdef(use_specs).
-spec find_child(Supervisor, Name) -> [pid()] when
Supervisor :: sup_ref(),
Name :: child_id().
-endif.
find_child(Supervisor, Name) ->
[Pid || {Name1, Pid, _Type, _Modules} <- which_children(Supervisor),
Name1 =:= Name].
call(Supervisor, Req) ->
gen_server:call(Supervisor, Req, infinity).
-ifdef(use_specs).
-spec check_childspecs(ChildSpecs) -> Result when
ChildSpecs :: [child_spec()],
Result :: 'ok' | {'error', Error :: term()}.
-endif.
check_childspecs(ChildSpecs) when is_list(ChildSpecs) ->
case check_startspec(ChildSpecs) of
{ok, _} -> ok;
Error -> {error, Error}
end;
check_childspecs(X) -> {error, {badarg, X}}.
%%%-----------------------------------------------------------------
%%% Called by timer:apply_after from restart/2
-ifdef(use_specs).
-spec try_again_restart(SupRef, Child, Reason) -> ok when
SupRef :: sup_ref(),
Child :: child_id() | pid(),
Reason :: term().
-endif.
try_again_restart(Supervisor, Child, Reason) ->
cast(Supervisor, {try_again_restart, Child, Reason}).
cast(Supervisor, Req) ->
gen_server:cast(Supervisor, Req).
%%% ---------------------------------------------------
%%%
%%% Initialize the supervisor.
%%%
%%% ---------------------------------------------------
-ifdef(use_specs).
-type init_sup_name() :: sup_name() | 'self'.
-type stop_rsn() :: {'shutdown', term()}
| {'bad_return', {module(),'init', term()}}
| {'bad_start_spec', term()}
| {'start_spec', term()}
| {'supervisor_data', term()}.
-spec init({init_sup_name(), module(), [term()]}) ->
{'ok', state()} | 'ignore' | {'stop', stop_rsn()}.
-endif.
init({SupName, Mod, Args}) ->
process_flag(trap_exit, true),
case Mod:init(Args) of
{ok, {SupFlags, StartSpec}} ->
case init_state(SupName, SupFlags, Mod, Args) of
{ok, State} when ?is_simple(State) ->
init_dynamic(State, StartSpec);
{ok, State} ->
init_children(State, StartSpec);
Error ->
{stop, {supervisor_data, Error}}
end;
ignore ->
ignore;
Error ->
{stop, {bad_return, {Mod, init, Error}}}
end.
init_children(State, StartSpec) ->
SupName = State#state.name,
case check_startspec(StartSpec) of
{ok, Children} ->
case start_children(Children, SupName) of
{ok, NChildren} ->
{ok, State#state{children = NChildren}};
{error, NChildren, Reason} ->
terminate_children(NChildren, SupName),
{stop, {shutdown, Reason}}
end;
Error ->
{stop, {start_spec, Error}}
end.
init_dynamic(State, [StartSpec]) ->
case check_startspec([StartSpec]) of
{ok, Children} ->
{ok, State#state{children = Children}};
Error ->
{stop, {start_spec, Error}}
end;
init_dynamic(_State, StartSpec) ->
{stop, {bad_start_spec, StartSpec}}.
%%-----------------------------------------------------------------
%% Func: start_children/2
%% Args: Children = [child_rec()] in start order
%% SupName = {local, atom()} | {global, atom()} | {pid(), Mod}
%% Purpose: Start all children. The new list contains #child's
%% with pids.
%% Returns: {ok, NChildren} | {error, NChildren, Reason}
%% NChildren = [child_rec()] in termination order (reversed
%% start order)
%%-----------------------------------------------------------------
start_children(Children, SupName) -> start_children(Children, [], SupName).
start_children([Child|Chs], NChildren, SupName) ->
case do_start_child(SupName, Child) of
{ok, undefined} when Child#child.restart_type =:= temporary ->
start_children(Chs, NChildren, SupName);
{ok, Pid} ->
start_children(Chs, [Child#child{pid = Pid}|NChildren], SupName);
{ok, Pid, _Extra} ->
start_children(Chs, [Child#child{pid = Pid}|NChildren], SupName);
{error, Reason} ->
report_error(start_error, Reason, Child, SupName),
{error, lists:reverse(Chs) ++ [Child | NChildren],
{failed_to_start_child,Child#child.name,Reason}}
end;
start_children([], NChildren, _SupName) ->
{ok, NChildren}.
do_start_child(SupName, Child) ->
#child{mfargs = {M, F, Args}} = Child,
case catch apply(M, F, Args) of
{ok, Pid} when is_pid(Pid) ->
NChild = Child#child{pid = Pid},
report_progress(NChild, SupName),
{ok, Pid};
{ok, Pid, Extra} when is_pid(Pid) ->
NChild = Child#child{pid = Pid},
report_progress(NChild, SupName),
{ok, Pid, Extra};
ignore ->
{ok, undefined};
{error, What} -> {error, What};
What -> {error, What}
end.
do_start_child_i(M, F, A) ->
case catch apply(M, F, A) of
{ok, Pid} when is_pid(Pid) ->
{ok, Pid};
{ok, Pid, Extra} when is_pid(Pid) ->
{ok, Pid, Extra};
ignore ->
{ok, undefined};
{error, Error} ->
{error, Error};
What ->
{error, What}
end.
%%% ---------------------------------------------------
%%%
%%% Callback functions.
%%%
%%% ---------------------------------------------------
-ifdef(use_specs).
-type call() :: 'which_children' | 'count_children' | {_, _}. % XXX: refine
-spec handle_call(call(), term(), state()) -> {'reply', term(), state()}.
-endif.
handle_call({start_child, EArgs}, _From, State) when ?is_simple(State) ->
Child = hd(State#state.children),
#child{mfargs = {M, F, A}} = Child,
Args = A ++ EArgs,
case do_start_child_i(M, F, Args) of
{ok, undefined} when Child#child.restart_type =:= temporary ->
{reply, {ok, undefined}, State};
{ok, Pid} ->
NState = save_dynamic_child(Child#child.restart_type, Pid, Args, State),
{reply, {ok, Pid}, NState};
{ok, Pid, Extra} ->
NState = save_dynamic_child(Child#child.restart_type, Pid, Args, State),
{reply, {ok, Pid, Extra}, NState};
What ->
{reply, What, State}
end;
%% terminate_child for simple_one_for_one can only be done with pid
handle_call({terminate_child, Name}, _From, State) when not is_pid(Name),
?is_simple(State) ->
{reply, {error, simple_one_for_one}, State};
handle_call({terminate_child, Name}, _From, State) ->
case get_child(Name, State, ?is_simple(State)) of
{value, Child} ->
case do_terminate(Child, State#state.name) of
#child{restart_type=RT} when RT=:=temporary; ?is_simple(State) ->
{reply, ok, state_del_child(Child, State)};
NChild ->
{reply, ok, replace_child(NChild, State)}
end;
false ->
{reply, {error, not_found}, State}
end;
%%% The requests delete_child and restart_child are invalid for
%%% simple_one_for_one supervisors.
handle_call({_Req, _Data}, _From, State) when ?is_simple(State) ->
{reply, {error, simple_one_for_one}, State};
handle_call({start_child, ChildSpec}, _From, State) ->
case check_childspec(ChildSpec) of
{ok, Child} ->
{Resp, NState} = handle_start_child(Child, State),
{reply, Resp, NState};
What ->
{reply, {error, What}, State}
end;
handle_call({restart_child, Name}, _From, State) ->
case get_child(Name, State) of
{value, Child} when Child#child.pid =:= undefined ->
case do_start_child(State#state.name, Child) of
{ok, Pid} ->
NState = replace_child(Child#child{pid = Pid}, State),
{reply, {ok, Pid}, NState};
{ok, Pid, Extra} ->
NState = replace_child(Child#child{pid = Pid}, State),
{reply, {ok, Pid, Extra}, NState};
Error ->
{reply, Error, State}
end;
{value, #child{pid=?restarting(_)}} ->
{reply, {error, restarting}, State};
{value, _} ->
{reply, {error, running}, State};
_ ->
{reply, {error, not_found}, State}
end;
handle_call({delete_child, Name}, _From, State) ->
case get_child(Name, State) of
{value, Child} when Child#child.pid =:= undefined ->
NState = remove_child(Child, State),
{reply, ok, NState};
{value, #child{pid=?restarting(_)}} ->
{reply, {error, restarting}, State};
{value, _} ->
{reply, {error, running}, State};
_ ->
{reply, {error, not_found}, State}
end;
handle_call(which_children, _From, #state{children = [#child{restart_type = temporary,
child_type = CT,
modules = Mods}]} =
State) when ?is_simple(State) ->
Reply = lists:map(fun(Pid) -> {undefined, Pid, CT, Mods} end,
?SETS:to_list(dynamics_db(temporary, State#state.dynamics))),
{reply, Reply, State};
handle_call(which_children, _From, #state{children = [#child{restart_type = RType,
child_type = CT,
modules = Mods}]} =
State) when ?is_simple(State) ->
Reply = lists:map(fun({?restarting(_),_}) -> {undefined,restarting,CT,Mods};
({Pid, _}) -> {undefined, Pid, CT, Mods} end,
?DICT:to_list(dynamics_db(RType, State#state.dynamics))),
{reply, Reply, State};
handle_call(which_children, _From, State) ->
Resp =
lists:map(fun(#child{pid = ?restarting(_), name = Name,
child_type = ChildType, modules = Mods}) ->
{Name, restarting, ChildType, Mods};
(#child{pid = Pid, name = Name,
child_type = ChildType, modules = Mods}) ->
{Name, Pid, ChildType, Mods}
end,
State#state.children),
{reply, Resp, State};
handle_call(count_children, _From, #state{children = [#child{restart_type = temporary,
child_type = CT}]} = State)
when ?is_simple(State) ->
{Active, Count} =
?SETS:fold(fun(Pid, {Alive, Tot}) ->
case is_pid(Pid) andalso is_process_alive(Pid) of
true ->{Alive+1, Tot +1};
false ->
{Alive, Tot + 1}
end
end, {0, 0}, dynamics_db(temporary, State#state.dynamics)),
Reply = case CT of
supervisor -> [{specs, 1}, {active, Active},
{supervisors, Count}, {workers, 0}];
worker -> [{specs, 1}, {active, Active},
{supervisors, 0}, {workers, Count}]
end,
{reply, Reply, State};
handle_call(count_children, _From, #state{children = [#child{restart_type = RType,
child_type = CT}]} = State)
when ?is_simple(State) ->
{Active, Count} =
?DICT:fold(fun(Pid, _Val, {Alive, Tot}) ->
case is_pid(Pid) andalso is_process_alive(Pid) of
true ->
{Alive+1, Tot +1};
false ->
{Alive, Tot + 1}
end
end, {0, 0}, dynamics_db(RType, State#state.dynamics)),
Reply = case CT of
supervisor -> [{specs, 1}, {active, Active},
{supervisors, Count}, {workers, 0}];
worker -> [{specs, 1}, {active, Active},
{supervisors, 0}, {workers, Count}]
end,
{reply, Reply, State};
handle_call(count_children, _From, State) ->
%% Specs and children are together on the children list...
{Specs, Active, Supers, Workers} =
lists:foldl(fun(Child, Counts) ->
count_child(Child, Counts)
end, {0,0,0,0}, State#state.children),
%% Reformat counts to a property list.
Reply = [{specs, Specs}, {active, Active},
{supervisors, Supers}, {workers, Workers}],
{reply, Reply, State}.
count_child(#child{pid = Pid, child_type = worker},
{Specs, Active, Supers, Workers}) ->
case is_pid(Pid) andalso is_process_alive(Pid) of
true -> {Specs+1, Active+1, Supers, Workers+1};
false -> {Specs+1, Active, Supers, Workers+1}
end;
count_child(#child{pid = Pid, child_type = supervisor},
{Specs, Active, Supers, Workers}) ->
case is_pid(Pid) andalso is_process_alive(Pid) of
true -> {Specs+1, Active+1, Supers+1, Workers};
false -> {Specs+1, Active, Supers+1, Workers}
end.
%%% If a restart attempt failed, this message is sent via
%%% timer:apply_after(0,...) in order to give gen_server the chance to
%%% check it's inbox before trying again.
-ifdef(use_specs).
-spec handle_cast({try_again_restart, child_id() | pid(), term()}, state()) ->
{'noreply', state()} | {stop, shutdown, state()}.
-endif.
handle_cast({try_again_restart,Pid,Reason}, #state{children=[Child]}=State)
when ?is_simple(State) ->
RT = Child#child.restart_type,
RPid = restarting(Pid),
case dynamic_child_args(RPid, dynamics_db(RT, State#state.dynamics)) of
{ok, Args} ->
{M, F, _} = Child#child.mfargs,
NChild = Child#child{pid = RPid, mfargs = {M, F, Args}},
try_restart(Child#child.restart_type, Reason, NChild, State);
error ->
{noreply, State}
end;
handle_cast({try_again_restart,Name,Reason}, State) ->
%% we still support >= R12-B3 in which lists:keyfind/3 doesn't exist
case lists:keysearch(Name,#child.name,State#state.children) of
{value, Child = #child{pid=?restarting(_), restart_type=RestartType}} ->
try_restart(RestartType, Reason, Child, State);
_ ->
{noreply,State}
end.
%%
%% Take care of terminated children.
%%
-ifdef(use_specs).
-spec handle_info(term(), state()) ->
{'noreply', state()} | {'stop', 'shutdown', state()}.
-endif.
handle_info({'EXIT', Pid, Reason}, State) ->
case restart_child(Pid, Reason, State) of
{ok, State1} ->
{noreply, State1};
{shutdown, State1} ->
{stop, shutdown, State1}
end;
handle_info({delayed_restart, {RestartType, Reason, Child}}, State)
when ?is_simple(State) ->
try_restart(RestartType, Reason, Child, State#state{restarts = []}); %% [1]
handle_info({delayed_restart, {RestartType, Reason, Child}}, State) ->
case get_child(Child#child.name, State) of
{value, Child1} ->
try_restart(RestartType, Reason, Child1,
State#state{restarts = []}); %% [1]
_What ->
{noreply, State}
end;
%% [1] When we receive a delayed_restart message we want to reset the
%% restarts field since otherwise the MaxT might not have elapsed and
%% we would just delay again and again. Since a common use of the
%% delayed restart feature is for MaxR = 1, MaxT = some huge number
%% (so that we don't end up bouncing around in non-delayed restarts)
%% this is important.
handle_info(Msg, State) ->
error_logger:error_msg("Supervisor received unexpected message: ~p~n",
[Msg]),
{noreply, State}.
%%
%% Terminate this server.
%%
-ifdef(use_specs).
-spec terminate(term(), state()) -> 'ok'.
-endif.
terminate(_Reason, #state{children=[Child]} = State) when ?is_simple(State) ->
terminate_dynamic_children(Child, dynamics_db(Child#child.restart_type,
State#state.dynamics),
State#state.name);
terminate(_Reason, State) ->
terminate_children(State#state.children, State#state.name).
%%
%% Change code for the supervisor.
%% Call the new call-back module and fetch the new start specification.
%% Combine the new spec. with the old. If the new start spec. is
%% not valid the code change will not succeed.
%% Use the old Args as argument to Module:init/1.
%% NOTE: This requires that the init function of the call-back module
%% does not have any side effects.
%%
-ifdef(use_specs).
-spec code_change(term(), state(), term()) ->
{'ok', state()} | {'error', term()}.
-endif.
code_change(_, State, _) ->
case (State#state.module):init(State#state.args) of
{ok, {SupFlags, StartSpec}} ->
case catch check_flags(SupFlags) of
ok ->
{Strategy, MaxIntensity, Period} = SupFlags,
update_childspec(State#state{strategy = Strategy,
intensity = MaxIntensity,
period = Period},
StartSpec);
Error ->
{error, Error}
end;
ignore ->
{ok, State};
Error ->
Error
end.
check_flags({Strategy, MaxIntensity, Period}) ->
validStrategy(Strategy),
validIntensity(MaxIntensity),
validPeriod(Period),
ok;
check_flags(What) ->
{bad_flags, What}.
update_childspec(State, StartSpec) when ?is_simple(State) ->
case check_startspec(StartSpec) of
{ok, [Child]} ->
{ok, State#state{children = [Child]}};
Error ->
{error, Error}
end;
update_childspec(State, StartSpec) ->
case check_startspec(StartSpec) of
{ok, Children} ->
OldC = State#state.children, % In reverse start order !
NewC = update_childspec1(OldC, Children, []),
{ok, State#state{children = NewC}};
Error ->
{error, Error}
end.
update_childspec1([Child|OldC], Children, KeepOld) ->
case update_chsp(Child, Children) of
{ok,NewChildren} ->
update_childspec1(OldC, NewChildren, KeepOld);
false ->
update_childspec1(OldC, Children, [Child|KeepOld])
end;
update_childspec1([], Children, KeepOld) ->
%% Return them in (kept) reverse start order.
lists:reverse(Children ++ KeepOld).
update_chsp(OldCh, Children) ->
case lists:map(fun(Ch) when OldCh#child.name =:= Ch#child.name ->
Ch#child{pid = OldCh#child.pid};
(Ch) ->
Ch
end,
Children) of
Children ->
false; % OldCh not found in new spec.
NewC ->
{ok, NewC}
end.
%%% ---------------------------------------------------
%%% Start a new child.
%%% ---------------------------------------------------
handle_start_child(Child, State) ->
case get_child(Child#child.name, State) of
false ->
case do_start_child(State#state.name, Child) of
{ok, undefined} when Child#child.restart_type =:= temporary ->
{{ok, undefined}, State};
{ok, Pid} ->
{{ok, Pid}, save_child(Child#child{pid = Pid}, State)};
{ok, Pid, Extra} ->
{{ok, Pid, Extra}, save_child(Child#child{pid = Pid}, State)};
{error, What} ->
{{error, {What, Child}}, State}
end;
{value, OldChild} when is_pid(OldChild#child.pid) ->
{{error, {already_started, OldChild#child.pid}}, State};
{value, _OldChild} ->
{{error, already_present}, State}
end.
%%% ---------------------------------------------------
%%% Restart. A process has terminated.
%%% Returns: {ok, state()} | {shutdown, state()}
%%% ---------------------------------------------------
restart_child(Pid, Reason, #state{children = [Child]} = State) when ?is_simple(State) ->
RestartType = Child#child.restart_type,
case dynamic_child_args(Pid, dynamics_db(RestartType, State#state.dynamics)) of
{ok, Args} ->
{M, F, _} = Child#child.mfargs,
NChild = Child#child{pid = Pid, mfargs = {M, F, Args}},
do_restart(RestartType, Reason, NChild, State);
error ->
{ok, State}
end;
restart_child(Pid, Reason, State) ->
Children = State#state.children,
%% we still support >= R12-B3 in which lists:keyfind/3 doesn't exist
case lists:keysearch(Pid, #child.pid, Children) of
{value, #child{restart_type = RestartType} = Child} ->
do_restart(RestartType, Reason, Child, State);
false ->
{ok, State}
end.
try_restart(RestartType, Reason, Child, State) ->
case handle_restart(RestartType, Reason, Child, State) of
{ok, NState} -> {noreply, NState};
{shutdown, State2} -> {stop, shutdown, State2}
end.
do_restart(RestartType, Reason, Child, State) ->
maybe_report_error(RestartType, Reason, Child, State),
handle_restart(RestartType, Reason, Child, State).
maybe_report_error(permanent, Reason, Child, State) ->
report_child_termination(Reason, Child, State);
maybe_report_error({permanent, _}, Reason, Child, State) ->
report_child_termination(Reason, Child, State);
maybe_report_error(_Type, Reason, Child, State) ->
case is_abnormal_termination(Reason) of
true -> report_child_termination(Reason, Child, State);
false -> ok
end.
report_child_termination(Reason, Child, State) ->
report_error(child_terminated, Reason, Child, State#state.name).
handle_restart(permanent, _Reason, Child, State) ->
restart(Child, State);
handle_restart(transient, Reason, Child, State) ->
restart_if_explicit_or_abnormal(fun restart/2,
fun delete_child_and_continue/2,
Reason, Child, State);
handle_restart(intrinsic, Reason, Child, State) ->
restart_if_explicit_or_abnormal(fun restart/2,
fun delete_child_and_stop/2,
Reason, Child, State);
handle_restart(temporary, _Reason, Child, State) ->
delete_child_and_continue(Child, State);
handle_restart({permanent, _Delay}=Restart, Reason, Child, State) ->
do_restart_delay(Restart, Reason, Child, State);
handle_restart({transient, _Delay}=Restart, Reason, Child, State) ->
restart_if_explicit_or_abnormal(defer_to_restart_delay(Restart, Reason),
fun delete_child_and_continue/2,
Reason, Child, State);
handle_restart({intrinsic, _Delay}=Restart, Reason, Child, State) ->
restart_if_explicit_or_abnormal(defer_to_restart_delay(Restart, Reason),
fun delete_child_and_stop/2,
Reason, Child, State).
restart_if_explicit_or_abnormal(RestartHow, Otherwise, Reason, Child, State) ->
case ?is_explicit_restart(Reason) orelse is_abnormal_termination(Reason) of
true -> RestartHow(Child, State);
false -> Otherwise(Child, State)
end.
defer_to_restart_delay(Restart, Reason) ->
fun(Child, State) -> do_restart_delay(Restart, Reason, Child, State) end.
delete_child_and_continue(Child, State) ->
{ok, state_del_child(Child, State)}.
delete_child_and_stop(Child, State) ->
{shutdown, state_del_child(Child, State)}.
is_abnormal_termination(normal) -> false;
is_abnormal_termination(shutdown) -> false;
is_abnormal_termination({shutdown, _}) -> false;
is_abnormal_termination(_Other) -> true.
do_restart_delay({RestartType, Delay}, Reason, Child, State) ->
case add_restart(State) of
{ok, NState} ->
maybe_restart(NState#state.strategy, Child, NState);
{terminate, _NState} ->
%% we've reached the max restart intensity, but the
%% add_restart will have added to the restarts
%% field. Given we don't want to die here, we need to go
%% back to the old restarts field otherwise we'll never
%% attempt to restart later, which is why we ignore
%% NState for this clause.
_TRef = erlang:send_after(trunc(Delay*1000), self(),
{delayed_restart,
{{RestartType, Delay}, Reason, Child}}),
{ok, state_del_child(Child, State)}
end.
restart(Child, State) ->
case add_restart(State) of
{ok, NState} ->
maybe_restart(NState#state.strategy, Child, NState);
{terminate, NState} ->
report_error(shutdown, reached_max_restart_intensity,
Child, State#state.name),
{shutdown, remove_child(Child, NState)}
end.
maybe_restart(Strategy, Child, State) ->
case restart(Strategy, Child, State) of
{try_again, Reason, NState2} ->
%% Leaving control back to gen_server before
%% trying again. This way other incoming requsts
%% for the supervisor can be handled - e.g. a
%% shutdown request for the supervisor or the
%% child.
Id = if ?is_simple(State) -> Child#child.pid;
true -> Child#child.name
end,
timer:apply_after(0,?MODULE,try_again_restart,[self(),Id,Reason]),
{ok,NState2};
Other ->
Other
end.
restart(simple_one_for_one, Child, State) ->
#child{pid = OldPid, mfargs = {M, F, A}} = Child,
Dynamics = ?DICT:erase(OldPid, dynamics_db(Child#child.restart_type,
State#state.dynamics)),
case do_start_child_i(M, F, A) of
{ok, Pid} ->
NState = State#state{dynamics = ?DICT:store(Pid, A, Dynamics)},
{ok, NState};
{ok, Pid, _Extra} ->
NState = State#state{dynamics = ?DICT:store(Pid, A, Dynamics)},
{ok, NState};
{error, Error} ->
NState = State#state{dynamics = ?DICT:store(restarting(OldPid), A,
Dynamics)},
report_error(start_error, Error, Child, State#state.name),
{try_again, Error, NState}
end;
restart(one_for_one, Child, State) ->
OldPid = Child#child.pid,
case do_start_child(State#state.name, Child) of
{ok, Pid} ->
NState = replace_child(Child#child{pid = Pid}, State),
{ok, NState};
{ok, Pid, _Extra} ->
NState = replace_child(Child#child{pid = Pid}, State),
{ok, NState};
{error, Reason} ->
NState = replace_child(Child#child{pid = restarting(OldPid)}, State),
report_error(start_error, Reason, Child, State#state.name),
{try_again, Reason, NState}
end;
restart(rest_for_one, Child, State) ->
{ChAfter, ChBefore} = split_child(Child#child.pid, State#state.children),
ChAfter2 = terminate_children(ChAfter, State#state.name),
case start_children(ChAfter2, State#state.name) of
{ok, ChAfter3} ->
{ok, State#state{children = ChAfter3 ++ ChBefore}};
{error, ChAfter3, Reason} ->
NChild = Child#child{pid=restarting(Child#child.pid)},
NState = State#state{children = ChAfter3 ++ ChBefore},
{try_again, Reason, replace_child(NChild,NState)}
end;
restart(one_for_all, Child, State) ->