forked from gnosek/nginx-upstream-fair
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathngx_http_upstream_fair_module.c
1379 lines (1098 loc) · 41.6 KB
/
ngx_http_upstream_fair_module.c
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
/*
* Copyright (C) 2007 Grzegorz Nosek
* Work sponsored by Ezra Zygmuntowicz & EngineYard.com
*
* Based on nginx source (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
typedef struct {
ngx_uint_t nreq;
ngx_uint_t total_req;
ngx_uint_t last_req_id;
ngx_uint_t fails;
ngx_uint_t current_weight;
} ngx_http_upstream_fair_shared_t;
typedef struct ngx_http_upstream_fair_peers_s ngx_http_upstream_fair_peers_t;
typedef struct {
ngx_rbtree_node_t node;
ngx_uint_t generation;
uintptr_t peers; /* forms a unique cookie together with generation */
ngx_uint_t total_nreq;
ngx_uint_t total_requests;
ngx_atomic_t lock;
ngx_http_upstream_fair_shared_t stats[1];
} ngx_http_upstream_fair_shm_block_t;
/* ngx_spinlock is defined without a matching unlock primitive */
#define ngx_spinlock_unlock(lock) (void) ngx_atomic_cmp_set(lock, ngx_pid, 0)
typedef struct {
ngx_http_upstream_fair_shared_t *shared;
struct sockaddr *sockaddr;
socklen_t socklen;
ngx_str_t name;
ngx_uint_t weight;
ngx_uint_t max_fails;
time_t fail_timeout;
time_t accessed;
ngx_uint_t down:1;
#if (NGX_HTTP_SSL)
ngx_ssl_session_t *ssl_session; /* local to a process */
#endif
} ngx_http_upstream_fair_peer_t;
#define NGX_HTTP_UPSTREAM_FAIR_NO_RR (1<<26)
#define NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_IDLE (1<<27)
#define NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_PEAK (1<<28)
#define NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_MASK ((1<<27) | (1<<28))
enum { WM_DEFAULT = 0, WM_IDLE, WM_PEAK };
struct ngx_http_upstream_fair_peers_s {
ngx_http_upstream_fair_shm_block_t *shared;
ngx_uint_t current;
ngx_uint_t size_err:1;
ngx_uint_t no_rr:1;
ngx_uint_t weight_mode:2;
ngx_uint_t number;
ngx_str_t *name;
ngx_http_upstream_fair_peers_t *next; /* for backup peers support, not really used yet */
ngx_http_upstream_fair_peer_t peer[1];
};
#define NGX_PEER_INVALID (~0UL)
typedef struct {
ngx_http_upstream_fair_peers_t *peers;
ngx_uint_t current;
uintptr_t *tried;
uintptr_t *done;
uintptr_t data;
uintptr_t data2;
} ngx_http_upstream_fair_peer_data_t;
static ngx_int_t ngx_http_upstream_init_fair(ngx_conf_t *cf,
ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_get_fair_peer(ngx_peer_connection_t *pc,
void *data);
static void ngx_http_upstream_free_fair_peer(ngx_peer_connection_t *pc,
void *data, ngx_uint_t state);
static ngx_int_t ngx_http_upstream_init_fair_peer(ngx_http_request_t *r,
ngx_http_upstream_srv_conf_t *us);
static char *ngx_http_upstream_fair(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static char *ngx_http_upstream_fair_set_shm_size(ngx_conf_t *cf,
ngx_command_t *cmd, void *conf);
static ngx_int_t ngx_http_upstream_fair_init_module(ngx_cycle_t *cycle);
#if (NGX_HTTP_EXTENDED_STATUS)
static ngx_chain_t *ngx_http_upstream_fair_report_status(ngx_http_request_t *r,
ngx_int_t *length);
#endif
#if (NGX_HTTP_SSL)
static ngx_int_t ngx_http_upstream_fair_set_session(ngx_peer_connection_t *pc,
void *data);
static void ngx_http_upstream_fair_save_session(ngx_peer_connection_t *pc,
void *data);
#endif
static ngx_command_t ngx_http_upstream_fair_commands[] = {
{ ngx_string("fair"),
NGX_HTTP_UPS_CONF|NGX_CONF_ANY,
ngx_http_upstream_fair,
0,
0,
NULL },
{ ngx_string("upstream_fair_shm_size"),
NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
ngx_http_upstream_fair_set_shm_size,
0,
0,
NULL },
ngx_null_command
};
static ngx_http_module_t ngx_http_upstream_fair_module_ctx = {
NULL, /* preconfiguration */
NULL, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
NULL, /* create location configuration */
NULL, /* merge location configuration */
#if (NGX_HTTP_EXTENDED_STATUS)
ngx_http_upstream_fair_report_status,
#endif
};
ngx_module_t ngx_http_upstream_fair_module = {
NGX_MODULE_V1,
&ngx_http_upstream_fair_module_ctx, /* module context */
ngx_http_upstream_fair_commands, /* module directives */
NGX_HTTP_MODULE, /* module type */
NULL, /* init master */
ngx_http_upstream_fair_init_module, /* init module */
NULL, /* init process */
NULL, /* init thread */
NULL, /* exit thread */
NULL, /* exit process */
NULL, /* exit master */
NGX_MODULE_V1_PADDING
};
static ngx_uint_t ngx_http_upstream_fair_shm_size;
static ngx_shm_zone_t * ngx_http_upstream_fair_shm_zone;
static ngx_rbtree_t * ngx_http_upstream_fair_rbtree;
static ngx_uint_t ngx_http_upstream_fair_generation;
static int
ngx_http_upstream_fair_compare_rbtree_node(const ngx_rbtree_node_t *v_left,
const ngx_rbtree_node_t *v_right)
{
ngx_http_upstream_fair_shm_block_t *left, *right;
left = (ngx_http_upstream_fair_shm_block_t *) v_left;
right = (ngx_http_upstream_fair_shm_block_t *) v_right;
if (left->generation < right->generation) {
return -1;
} else if (left->generation > right->generation) {
return 1;
} else { /* left->generation == right->generation */
if (left->peers < right->peers) {
return -1;
} else if (left->peers > right->peers) {
return 1;
} else {
return 0;
}
}
}
/*
* generic functions start here
*/
static void
ngx_rbtree_generic_insert(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel,
int (*compare)(const ngx_rbtree_node_t *left, const ngx_rbtree_node_t *right))
{
for ( ;; ) {
if (node->key < temp->key) {
if (temp->left == sentinel) {
temp->left = node;
break;
}
temp = temp->left;
} else if (node->key > temp->key) {
if (temp->right == sentinel) {
temp->right = node;
break;
}
temp = temp->right;
} else { /* node->key == temp->key */
if (compare(node, temp) < 0) {
if (temp->left == sentinel) {
temp->left = node;
break;
}
temp = temp->left;
} else {
if (temp->right == sentinel) {
temp->right = node;
break;
}
temp = temp->right;
}
}
}
node->parent = temp;
node->left = sentinel;
node->right = sentinel;
ngx_rbt_red(node);
}
#define NGX_BITVECTOR_ELT_SIZE (sizeof(uintptr_t) * 8)
static uintptr_t *
ngx_bitvector_alloc(ngx_pool_t *pool, ngx_uint_t size, uintptr_t *small)
{
ngx_uint_t nelts = (size + NGX_BITVECTOR_ELT_SIZE - 1) / NGX_BITVECTOR_ELT_SIZE;
if (small && nelts == 1) {
*small = 0;
return small;
}
return ngx_pcalloc(pool, nelts * NGX_BITVECTOR_ELT_SIZE);
}
static ngx_int_t
ngx_bitvector_test(uintptr_t *bv, ngx_uint_t bit)
{
ngx_uint_t n, m;
n = bit / NGX_BITVECTOR_ELT_SIZE;
m = 1 << (bit % NGX_BITVECTOR_ELT_SIZE);
return bv[n] & m;
}
static void
ngx_bitvector_set(uintptr_t *bv, ngx_uint_t bit)
{
ngx_uint_t n, m;
n = bit / NGX_BITVECTOR_ELT_SIZE;
m = 1 << (bit % NGX_BITVECTOR_ELT_SIZE);
bv[n] |= m;
}
/*
* generic functions end here
*/
static ngx_int_t
ngx_http_upstream_fair_init_module(ngx_cycle_t *cycle)
{
ngx_http_upstream_fair_generation++;
return NGX_OK;
}
static void
ngx_http_upstream_fair_rbtree_insert(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) {
ngx_rbtree_generic_insert(temp, node, sentinel,
ngx_http_upstream_fair_compare_rbtree_node);
}
static ngx_int_t
ngx_http_upstream_fair_init_shm_zone(ngx_shm_zone_t *shm_zone, void *data)
{
ngx_slab_pool_t *shpool;
ngx_rbtree_t *tree;
ngx_rbtree_node_t *sentinel;
if (data) {
shm_zone->data = data;
return NGX_OK;
}
shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
tree = ngx_slab_alloc(shpool, sizeof *tree);
if (tree == NULL) {
return NGX_ERROR;
}
sentinel = ngx_slab_alloc(shpool, sizeof *sentinel);
if (sentinel == NULL) {
return NGX_ERROR;
}
ngx_rbtree_sentinel_init(sentinel);
tree->root = sentinel;
tree->sentinel = sentinel;
tree->insert = ngx_http_upstream_fair_rbtree_insert;
shm_zone->data = tree;
ngx_http_upstream_fair_rbtree = tree;
return NGX_OK;
}
static char *
ngx_http_upstream_fair_set_shm_size(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ssize_t new_shm_size;
ngx_str_t *value;
value = cf->args->elts;
new_shm_size = ngx_parse_size(&value[1]);
if (new_shm_size == NGX_ERROR) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "Invalid memory area size `%V'", &value[1]);
return NGX_CONF_ERROR;
}
new_shm_size = ngx_align(new_shm_size, ngx_pagesize);
if (new_shm_size < 8 * (ssize_t) ngx_pagesize) {
ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "The upstream_fair_shm_size value must be at least %udKiB", (8 * ngx_pagesize) >> 10);
new_shm_size = 8 * ngx_pagesize;
}
if (ngx_http_upstream_fair_shm_size &&
ngx_http_upstream_fair_shm_size != (ngx_uint_t) new_shm_size) {
ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "Cannot change memory area size without restart, ignoring change");
} else {
ngx_http_upstream_fair_shm_size = new_shm_size;
}
ngx_conf_log_error(NGX_LOG_DEBUG, cf, 0, "Using %udKiB of shared memory for upstream_fair", new_shm_size >> 10);
return NGX_CONF_OK;
}
static char *
ngx_http_upstream_fair(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_upstream_srv_conf_t *uscf;
ngx_uint_t i;
ngx_uint_t extra_peer_flags = 0;
for (i = 1; i < cf->args->nelts; i++) {
ngx_str_t *value = cf->args->elts;
if (ngx_strcmp(value[i].data, "no_rr") == 0) {
extra_peer_flags |= NGX_HTTP_UPSTREAM_FAIR_NO_RR;
} else if (ngx_strcmp(value[i].data, "weight_mode=peak") == 0) {
if (extra_peer_flags & NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_MASK) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "weight_mode= options are mutually exclusive");
return NGX_CONF_ERROR;
}
extra_peer_flags |= NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_PEAK;
} else if (ngx_strcmp(value[i].data, "weight_mode=idle") == 0) {
if (extra_peer_flags & NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_MASK) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "weight_mode= options are mutually exclusive");
return NGX_CONF_ERROR;
}
extra_peer_flags |= NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_IDLE;
} else {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "Invalid `fair' parameter `%V'", &value[i]);
return NGX_CONF_ERROR;
}
}
uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);
uscf->peer.init_upstream = ngx_http_upstream_init_fair;
uscf->flags = NGX_HTTP_UPSTREAM_CREATE
|NGX_HTTP_UPSTREAM_WEIGHT
|NGX_HTTP_UPSTREAM_MAX_FAILS
|NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
|NGX_HTTP_UPSTREAM_DOWN
|extra_peer_flags;
return NGX_CONF_OK;
}
static ngx_int_t
ngx_http_upstream_cmp_servers(const void *one, const void *two)
{
const ngx_http_upstream_fair_peer_t *first, *second;
first = one;
second = two;
return (first->weight < second->weight);
}
/* TODO: Actually support backup servers */
static ngx_int_t
ngx_http_upstream_init_fair_rr(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
{
ngx_url_t u;
ngx_uint_t i, j, n;
ngx_http_upstream_server_t *server;
ngx_http_upstream_fair_peers_t *peers, *backup;
if (us->servers) {
server = us->servers->elts;
n = 0;
for (i = 0; i < us->servers->nelts; i++) {
if (server[i].backup) {
continue;
}
n += server[i].naddrs;
}
peers = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_fair_peers_t)
+ sizeof(ngx_http_upstream_fair_peer_t) * (n - 1));
if (peers == NULL) {
return NGX_ERROR;
}
peers->number = n;
peers->name = &us->host;
n = 0;
for (i = 0; i < us->servers->nelts; i++) {
for (j = 0; j < server[i].naddrs; j++) {
if (server[i].backup) {
continue;
}
peers->peer[n].sockaddr = server[i].addrs[j].sockaddr;
peers->peer[n].socklen = server[i].addrs[j].socklen;
peers->peer[n].name = server[i].addrs[j].name;
peers->peer[n].max_fails = server[i].max_fails;
peers->peer[n].fail_timeout = server[i].fail_timeout;
peers->peer[n].down = server[i].down;
peers->peer[n].weight = server[i].down ? 0 : server[i].weight;
n++;
}
}
us->peer.data = peers;
ngx_sort(&peers->peer[0], (size_t) n,
sizeof(ngx_http_upstream_fair_peer_t),
ngx_http_upstream_cmp_servers);
/* backup servers */
n = 0;
for (i = 0; i < us->servers->nelts; i++) {
if (!server[i].backup) {
continue;
}
n += server[i].naddrs;
}
if (n == 0) {
return NGX_OK;
}
backup = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_fair_peers_t)
+ sizeof(ngx_http_upstream_fair_peer_t) * (n - 1));
if (backup == NULL) {
return NGX_ERROR;
}
backup->number = n;
backup->name = &us->host;
n = 0;
for (i = 0; i < us->servers->nelts; i++) {
for (j = 0; j < server[i].naddrs; j++) {
if (!server[i].backup) {
continue;
}
backup->peer[n].sockaddr = server[i].addrs[j].sockaddr;
backup->peer[n].socklen = server[i].addrs[j].socklen;
backup->peer[n].name = server[i].addrs[j].name;
backup->peer[n].weight = server[i].weight;
backup->peer[n].max_fails = server[i].max_fails;
backup->peer[n].fail_timeout = server[i].fail_timeout;
backup->peer[n].down = server[i].down;
n++;
}
}
peers->next = backup;
ngx_sort(&backup->peer[0], (size_t) n,
sizeof(ngx_http_upstream_fair_peer_t),
ngx_http_upstream_cmp_servers);
return NGX_OK;
}
/* an upstream implicitly defined by proxy_pass, etc. */
#if nginx_version < 1011006
if (us->port == 0 && us->default_port == 0) {
#else
if (us->port == 0) {
#endif
ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
"no port in upstream \"%V\" in %s:%ui",
&us->host, us->file_name, us->line);
return NGX_ERROR;
}
ngx_memzero(&u, sizeof(ngx_url_t));
u.host = us->host;
#if nginx_version < 1011006
u.port = (in_port_t) (us->port ? us->port : us->default_port);
#else
u.port = (in_port_t) us->port;
#endif
if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
if (u.err) {
ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
"%s in upstream \"%V\" in %s:%ui",
u.err, &us->host, us->file_name, us->line);
}
return NGX_ERROR;
}
n = u.naddrs;
peers = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_fair_peers_t)
+ sizeof(ngx_http_upstream_fair_peer_t) * (n - 1));
if (peers == NULL) {
return NGX_ERROR;
}
peers->number = n;
peers->name = &us->host;
for (i = 0; i < u.naddrs; i++) {
peers->peer[i].sockaddr = u.addrs[i].sockaddr;
peers->peer[i].socklen = u.addrs[i].socklen;
peers->peer[i].name = u.addrs[i].name;
peers->peer[i].weight = 1;
peers->peer[i].max_fails = 1;
peers->peer[i].fail_timeout = 10;
}
us->peer.data = peers;
/* implicitly defined upstream has no backup servers */
return NGX_OK;
}
static ngx_int_t
ngx_http_upstream_init_fair(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
{
ngx_http_upstream_fair_peers_t *peers;
ngx_uint_t n;
ngx_str_t *shm_name;
/* do the dirty work using rr module */
if (ngx_http_upstream_init_fair_rr(cf, us) != NGX_OK) {
return NGX_ERROR;
}
/* setup our wrapper around rr */
peers = ngx_palloc(cf->pool, sizeof *peers);
if (peers == NULL) {
return NGX_ERROR;
}
peers = us->peer.data;
n = peers->number;
shm_name = ngx_palloc(cf->pool, sizeof *shm_name);
shm_name->len = sizeof("upstream_fair") - 1;
shm_name->data = (unsigned char *) "upstream_fair";
if (ngx_http_upstream_fair_shm_size == 0) {
ngx_http_upstream_fair_shm_size = 8 * ngx_pagesize;
}
ngx_http_upstream_fair_shm_zone = ngx_shared_memory_add(
cf, shm_name, ngx_http_upstream_fair_shm_size, &ngx_http_upstream_fair_module);
if (ngx_http_upstream_fair_shm_zone == NULL) {
return NGX_ERROR;
}
ngx_http_upstream_fair_shm_zone->init = ngx_http_upstream_fair_init_shm_zone;
peers->shared = NULL;
peers->current = n - 1;
if (us->flags & NGX_HTTP_UPSTREAM_FAIR_NO_RR) {
peers->no_rr = 1;
}
if (us->flags & NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_IDLE) {
peers->weight_mode = WM_IDLE;
} else if (us->flags & NGX_HTTP_UPSTREAM_FAIR_WEIGHT_MODE_PEAK) {
peers->weight_mode = WM_PEAK;
}
peers->size_err = 0;
us->peer.init = ngx_http_upstream_init_fair_peer;
return NGX_OK;
}
static void
ngx_http_upstream_fair_update_nreq(ngx_http_upstream_fair_peer_data_t *fp, int delta, ngx_log_t *log)
{
#if (NGX_DEBUG)
ngx_uint_t nreq;
ngx_uint_t total_nreq;
nreq = (fp->peers->peer[fp->current].shared->nreq += delta);
total_nreq = (fp->peers->shared->total_nreq += delta);
ngx_log_debug6(NGX_LOG_DEBUG_HTTP, log, 0,
"[upstream_fair] nreq for peer %ui @ %p/%p now %d, total %d, delta %d",
fp->current, fp->peers, fp->peers->peer[fp->current].shared, nreq,
total_nreq, delta);
#endif
}
/*
* SCHED_COUNTER_BITS is the portion of an ngx_uint_t which represents
* the req_delta part (number of requests serviced on _other_
* backends). The rest (top bits) represents the number of currently
* processed requests.
*
* The value is not too critical because overflow is handled via
* saturation. With the default value of 20, scheduling is exact for
* fewer than 4k concurrent requests per backend (on 32-bit
* architectures) and fewer than 1M concurrent requests to all backends
* together. Beyond these limits, the algorithm essentially falls back
* to pure weighted round-robin.
*
* A higher score means less suitable.
*
* The `delta' parameter is bit-negated so that high values yield low
* scores and get chosen more often.
*/
#define SCHED_COUNTER_BITS 20
#define SCHED_NREQ_MAX ((~0UL) >> SCHED_COUNTER_BITS)
#define SCHED_COUNTER_MAX ((1 << SCHED_COUNTER_BITS) - 1)
#define SCHED_SCORE(nreq,delta) (((nreq) << SCHED_COUNTER_BITS) | (~(delta) & SCHED_COUNTER_MAX))
#define ngx_upstream_fair_min(a,b) (((a) < (b)) ? (a) : (b))
static ngx_uint_t
ngx_http_upstream_fair_sched_score(ngx_peer_connection_t *pc,
ngx_http_upstream_fair_peer_data_t *fp,
ngx_uint_t n)
{
ngx_http_upstream_fair_peer_t *peer = &fp->peers->peer[n];
ngx_http_upstream_fair_shared_t *fs = peer->shared;
ngx_uint_t req_delta = fp->peers->shared->total_requests - fs->last_req_id;
/* sanity check */
if ((ngx_int_t)fs->nreq < 0) {
ngx_log_error(NGX_LOG_WARN, pc->log, 0, "[upstream_fair] upstream %ui has negative nreq (%i)", n, fs->nreq);
return SCHED_SCORE(0, req_delta);
}
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] peer %ui: nreq = %i, req_delta = %ui", n, fs->nreq, req_delta);
return SCHED_SCORE(
ngx_upstream_fair_min(fs->nreq, SCHED_NREQ_MAX),
ngx_upstream_fair_min(req_delta, SCHED_COUNTER_MAX));
}
/*
* the core of load balancing logic
*/
static ngx_int_t
ngx_http_upstream_fair_try_peer(ngx_peer_connection_t *pc,
ngx_http_upstream_fair_peer_data_t *fp,
ngx_uint_t peer_id)
{
ngx_http_upstream_fair_peer_t *peer;
if (ngx_bitvector_test(fp->tried, peer_id))
return NGX_BUSY;
peer = &fp->peers->peer[peer_id];
if (!peer->down) {
if (peer->max_fails == 0 || peer->shared->fails < peer->max_fails) {
return NGX_OK;
}
if (ngx_time() - peer->accessed > peer->fail_timeout) {
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] resetting fail count for peer %d, time delta %d > %d",
peer_id, ngx_time() - peer->accessed, peer->fail_timeout);
peer->shared->fails = 0;
return NGX_OK;
}
}
return NGX_BUSY;
}
static ngx_uint_t
ngx_http_upstream_choose_fair_peer_idle(ngx_peer_connection_t *pc,
ngx_http_upstream_fair_peer_data_t *fp)
{
ngx_uint_t i, n;
ngx_uint_t npeers = fp->peers->number;
ngx_uint_t weight_mode = fp->peers->weight_mode;
ngx_uint_t best_idx = NGX_PEER_INVALID;
ngx_uint_t best_nreq = ~0U;
for (i = 0, n = fp->current; i < npeers; i++, n = (n + 1) % npeers) {
ngx_uint_t nreq = fp->peers->peer[n].shared->nreq;
ngx_uint_t weight = fp->peers->peer[n].weight;
if (fp->peers->peer[n].shared->fails > 0)
continue;
if (nreq >= weight || (nreq > 0 && weight_mode != WM_IDLE)) {
continue;
}
if (ngx_http_upstream_fair_try_peer(pc, fp, n) != NGX_OK) {
continue;
}
/* not in WM_IDLE+no_rr mode: the first completely idle backend gets chosen */
if (weight_mode != WM_IDLE || !fp->peers->no_rr) {
best_idx = n;
break;
}
/* in WM_IDLE+no_rr mode we actually prefer slightly loaded backends
* to totally idle ones, under the assumption that they're spawned
* on demand and can handle up to 'weight' concurrent requests
*/
if (best_idx == NGX_PEER_INVALID || nreq) {
if (best_nreq <= nreq) {
continue;
}
best_idx = n;
best_nreq = nreq;
}
}
return best_idx;
}
static ngx_int_t
ngx_http_upstream_choose_fair_peer_busy(ngx_peer_connection_t *pc,
ngx_http_upstream_fair_peer_data_t *fp)
{
ngx_uint_t i, n;
ngx_uint_t npeers = fp->peers->number;
ngx_uint_t weight_mode = fp->peers->weight_mode;
ngx_uint_t best_idx = NGX_PEER_INVALID;
ngx_uint_t sched_score;
ngx_uint_t best_sched_score = ~0UL;
/*
* calculate sched scores for all the peers, choosing the lowest one
*/
for (i = 0, n = fp->current; i < npeers; i++, n = (n + 1) % npeers) {
ngx_http_upstream_fair_peer_t *peer;
ngx_uint_t nreq;
ngx_uint_t weight;
peer = &fp->peers->peer[n];
nreq = fp->peers->peer[n].shared->nreq;
if (weight_mode == WM_PEAK && nreq >= peer->weight) {
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] backend %d has nreq %ui >= weight %ui in WM_PEAK mode", n, nreq, peer->weight);
continue;
}
if (ngx_http_upstream_fair_try_peer(pc, fp, n) != NGX_OK) {
if (!pc->tries) {
ngx_log_debug(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] all backends exhausted");
return NGX_PEER_INVALID;
}
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] backend %d already tried", n);
continue;
}
sched_score = ngx_http_upstream_fair_sched_score(pc, fp, n);
if (weight_mode == WM_DEFAULT) {
/*
* take peer weight into account
*/
weight = peer->shared->current_weight;
if (peer->max_fails) {
ngx_uint_t mf = peer->max_fails;
weight = peer->shared->current_weight * (mf - peer->shared->fails) / mf;
}
if (weight > 0) {
sched_score /= weight;
}
ngx_log_debug8(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] bss = %ui, ss = %ui (n = %d, w = %d/%d, f = %d/%d, weight = %d)",
best_sched_score, sched_score, n, peer->shared->current_weight, peer->weight, peer->shared->fails, peer->max_fails, weight);
}
if (sched_score <= best_sched_score) {
best_idx = n;
best_sched_score = sched_score;
}
}
return best_idx;
}
static ngx_int_t
ngx_http_upstream_choose_fair_peer(ngx_peer_connection_t *pc,
ngx_http_upstream_fair_peer_data_t *fp, ngx_uint_t *peer_id)
{
ngx_uint_t npeers;
ngx_uint_t best_idx = NGX_PEER_INVALID;
ngx_uint_t weight_mode;
npeers = fp->peers->number;
weight_mode = fp->peers->weight_mode;
/* just a single backend */
if (npeers == 1) {
*peer_id = 0;
return NGX_OK;
}
/* any idle backends? */
best_idx = ngx_http_upstream_choose_fair_peer_idle(pc, fp);
if (best_idx != NGX_PEER_INVALID) {
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] peer %i is idle", best_idx);
goto chosen;
}
/* no idle backends, choose the least loaded one */
best_idx = ngx_http_upstream_choose_fair_peer_busy(pc, fp);
if (best_idx != NGX_PEER_INVALID) {
goto chosen;
}
return NGX_BUSY;
chosen:
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] chose peer %i", best_idx);
*peer_id = best_idx;
ngx_bitvector_set(fp->tried, best_idx);
if (weight_mode == WM_DEFAULT) {
ngx_http_upstream_fair_peer_t *peer = &fp->peers->peer[best_idx];
if (peer->shared->current_weight-- == 0) {
peer->shared->current_weight = peer->weight;
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] peer %d expired weight, reset to %d", best_idx, peer->weight);
}
}
return NGX_OK;
}
ngx_int_t
ngx_http_upstream_get_fair_peer(ngx_peer_connection_t *pc, void *data)
{
ngx_int_t ret;
ngx_uint_t peer_id, i;
ngx_http_upstream_fair_peer_data_t *fp = data;
ngx_http_upstream_fair_peer_t *peer;
ngx_atomic_t *lock;
peer_id = fp->current;
fp->current = (fp->current + 1) % fp->peers->number;
lock = &fp->peers->shared->lock;
ngx_spinlock(lock, ngx_pid, 1024);
ret = ngx_http_upstream_choose_fair_peer(pc, fp, &peer_id);
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] fp->current = %d, peer_id = %d, ret = %d",
fp->current, peer_id, ret);
if (pc)
pc->tries--;
if (ret == NGX_BUSY) {
for (i = 0; i < fp->peers->number; i++) {
fp->peers->peer[i].shared->fails = 0;
}
pc->name = fp->peers->name;
fp->current = NGX_PEER_INVALID;
ngx_spinlock_unlock(lock);
return NGX_BUSY;
}
/* assert(ret == NGX_OK); */
peer = &fp->peers->peer[peer_id];
fp->current = peer_id;
if (!fp->peers->no_rr) {
fp->peers->current = peer_id;
}
pc->sockaddr = peer->sockaddr;
pc->socklen = peer->socklen;
pc->name = &peer->name;
peer->shared->last_req_id = fp->peers->shared->total_requests;
ngx_http_upstream_fair_update_nreq(fp, 1, pc->log);
peer->shared->total_req++;
ngx_spinlock_unlock(lock);
return ret;
}
void
ngx_http_upstream_free_fair_peer(ngx_peer_connection_t *pc, void *data,
ngx_uint_t state)
{
ngx_http_upstream_fair_peer_data_t *fp = data;
ngx_http_upstream_fair_peer_t *peer;
ngx_atomic_t *lock;
ngx_log_debug4(NGX_LOG_DEBUG_HTTP, pc->log, 0, "[upstream_fair] fp->current = %d, state = %ui, pc->tries = %d, pc->data = %p",
fp->current, state, pc->tries, pc->data);
if (fp->current == NGX_PEER_INVALID) {
return;
}
lock = &fp->peers->shared->lock;
ngx_spinlock(lock, ngx_pid, 1024);
if (!ngx_bitvector_test(fp->done, fp->current)) {
ngx_bitvector_set(fp->done, fp->current);
ngx_http_upstream_fair_update_nreq(fp, -1, pc->log);
}
if (fp->peers->number == 1) {
pc->tries = 0;
}
if (state & NGX_PEER_FAILED) {
peer = &fp->peers->peer[fp->current];
peer->shared->fails++;
peer->accessed = ngx_time();
}
ngx_spinlock_unlock(lock);
}
/*
* walk through the rbtree, removing old entries and looking for
* a matching one -- compared by (cycle, peers) pair
*
* no attempt at optimisation is made, for two reasons:
* - the tree will be quite small, anyway
* - being called once per worker startup per upstream block,
* this code isn't really the hot path