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comparison src/http/modules/ngx_http_upstream_random_module.c @ 7301:f2396ecf608b

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Upstream: ngx_http_upstream_random module. The module implements random load-balancing algorithm with optional second choice. In the latter case, the best of two servers is chosen, accounting number of connections and server weight. Example: upstream u { random [two [least_conn]]; server 127.0.0.1:8080; server 127.0.0.1:8081; server 127.0.0.1:8082; server 127.0.0.1:8083; }
author Vladimir Homutov <vl@nginx.com>
date Fri, 15 Jun 2018 11:46:14 +0300
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7300:ed599ea6c1f1 7301:f2396ecf608b
1
2 /*
3 * Copyright (C) Nginx, Inc.
4 */
5
6
7 #include <ngx_config.h>
8 #include <ngx_core.h>
9 #include <ngx_http.h>
10
11
12 typedef struct {
13 ngx_http_upstream_rr_peer_t *peer;
14 ngx_uint_t range;
15 } ngx_http_upstream_random_range_t;
16
17
18 typedef struct {
19 ngx_uint_t two;
20 ngx_http_upstream_random_range_t *ranges;
21 } ngx_http_upstream_random_srv_conf_t;
22
23
24 typedef struct {
25 /* the round robin data must be first */
26 ngx_http_upstream_rr_peer_data_t rrp;
27
28 ngx_http_upstream_random_srv_conf_t *conf;
29 u_char tries;
30 } ngx_http_upstream_random_peer_data_t;
31
32
33 static ngx_int_t ngx_http_upstream_init_random(ngx_conf_t *cf,
34 ngx_http_upstream_srv_conf_t *us);
35 static ngx_int_t ngx_http_upstream_update_random(ngx_pool_t *pool,
36 ngx_http_upstream_srv_conf_t *us);
37
38 static ngx_int_t ngx_http_upstream_init_random_peer(ngx_http_request_t *r,
39 ngx_http_upstream_srv_conf_t *us);
40 static ngx_int_t ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc,
41 void *data);
42 static ngx_int_t ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc,
43 void *data);
44 static ngx_uint_t ngx_http_upstream_peek_random_peer(
45 ngx_http_upstream_rr_peers_t *peers,
46 ngx_http_upstream_random_peer_data_t *rp);
47 static void *ngx_http_upstream_random_create_conf(ngx_conf_t *cf);
48 static char *ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd,
49 void *conf);
50
51
52 static ngx_command_t ngx_http_upstream_random_commands[] = {
53
54 { ngx_string("random"),
55 NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE12,
56 ngx_http_upstream_random,
57 NGX_HTTP_SRV_CONF_OFFSET,
58 0,
59 NULL },
60
61 ngx_null_command
62 };
63
64
65 static ngx_http_module_t ngx_http_upstream_random_module_ctx = {
66 NULL, /* preconfiguration */
67 NULL, /* postconfiguration */
68
69 NULL, /* create main configuration */
70 NULL, /* init main configuration */
71
72 ngx_http_upstream_random_create_conf, /* create server configuration */
73 NULL, /* merge server configuration */
74
75 NULL, /* create location configuration */
76 NULL /* merge location configuration */
77 };
78
79
80 ngx_module_t ngx_http_upstream_random_module = {
81 NGX_MODULE_V1,
82 &ngx_http_upstream_random_module_ctx, /* module context */
83 ngx_http_upstream_random_commands, /* module directives */
84 NGX_HTTP_MODULE, /* module type */
85 NULL, /* init master */
86 NULL, /* init module */
87 NULL, /* init process */
88 NULL, /* init thread */
89 NULL, /* exit thread */
90 NULL, /* exit process */
91 NULL, /* exit master */
92 NGX_MODULE_V1_PADDING
93 };
94
95
96 static ngx_int_t
97 ngx_http_upstream_init_random(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
98 {
99 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0, "init random");
100
101 if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
102 return NGX_ERROR;
103 }
104
105 us->peer.init = ngx_http_upstream_init_random_peer;
106
107 #if (NGX_HTTP_UPSTREAM_ZONE)
108 if (us->shm_zone) {
109 return NGX_OK;
110 }
111 #endif
112
113 return ngx_http_upstream_update_random(cf->pool, us);
114 }
115
116
117 static ngx_int_t
118 ngx_http_upstream_update_random(ngx_pool_t *pool,
119 ngx_http_upstream_srv_conf_t *us)
120 {
121 size_t size;
122 ngx_uint_t i, total_weight;
123 ngx_http_upstream_rr_peer_t *peer;
124 ngx_http_upstream_rr_peers_t *peers;
125 ngx_http_upstream_random_range_t *ranges;
126 ngx_http_upstream_random_srv_conf_t *rcf;
127
128 rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);
129
130 peers = us->peer.data;
131
132 size = peers->number * sizeof(ngx_http_upstream_random_range_t);
133
134 ranges = pool ? ngx_palloc(pool, size) : ngx_alloc(size, ngx_cycle->log);
135 if (ranges == NULL) {
136 return NGX_ERROR;
137 }
138
139 total_weight = 0;
140
141 for (peer = peers->peer, i = 0; peer; peer = peer->next, i++) {
142 ranges[i].peer = peer;
143 ranges[i].range = total_weight;
144 total_weight += peer->weight;
145 }
146
147 rcf->ranges = ranges;
148
149 return NGX_OK;
150 }
151
152
153 static ngx_int_t
154 ngx_http_upstream_init_random_peer(ngx_http_request_t *r,
155 ngx_http_upstream_srv_conf_t *us)
156 {
157 ngx_http_upstream_random_srv_conf_t *rcf;
158 ngx_http_upstream_random_peer_data_t *rp;
159
160 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
161 "init random peer");
162
163 rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);
164
165 rp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_random_peer_data_t));
166 if (rp == NULL) {
167 return NGX_ERROR;
168 }
169
170 r->upstream->peer.data = &rp->rrp;
171
172 if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
173 return NGX_ERROR;
174 }
175
176 if (rcf->two) {
177 r->upstream->peer.get = ngx_http_upstream_get_random2_peer;
178
179 } else {
180 r->upstream->peer.get = ngx_http_upstream_get_random_peer;
181 }
182
183 rp->conf = rcf;
184 rp->tries = 0;
185
186 ngx_http_upstream_rr_peers_rlock(rp->rrp.peers);
187
188 #if (NGX_HTTP_UPSTREAM_ZONE)
189 if (rp->rrp.peers->shpool && rcf->ranges == NULL) {
190 if (ngx_http_upstream_update_random(NULL, us) != NGX_OK) {
191 ngx_http_upstream_rr_peers_unlock(rp->rrp.peers);
192 return NGX_ERROR;
193 }
194 }
195 #endif
196
197 ngx_http_upstream_rr_peers_unlock(rp->rrp.peers);
198
199 return NGX_OK;
200 }
201
202
203 static ngx_int_t
204 ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc, void *data)
205 {
206 ngx_http_upstream_random_peer_data_t *rp = data;
207
208 time_t now;
209 uintptr_t m;
210 ngx_uint_t i, n;
211 ngx_http_upstream_rr_peer_t *peer;
212 ngx_http_upstream_rr_peers_t *peers;
213 ngx_http_upstream_rr_peer_data_t *rrp;
214
215 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
216 "get random peer, try: %ui", pc->tries);
217
218 rrp = &rp->rrp;
219 peers = rrp->peers;
220
221 ngx_http_upstream_rr_peers_rlock(peers);
222
223 if (rp->tries > 20 || peers->single) {
224 ngx_http_upstream_rr_peers_unlock(peers);
225 return ngx_http_upstream_get_round_robin_peer(pc, rrp);
226 }
227
228 pc->cached = 0;
229 pc->connection = NULL;
230
231 now = ngx_time();
232
233 for ( ;; ) {
234
235 i = ngx_http_upstream_peek_random_peer(peers, rp);
236
237 peer = rp->conf->ranges[i].peer;
238
239 n = i / (8 * sizeof(uintptr_t));
240 m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
241
242 if (rrp->tried[n] & m) {
243 goto next;
244 }
245
246 ngx_http_upstream_rr_peer_lock(peers, peer);
247
248 if (peer->down) {
249 ngx_http_upstream_rr_peer_unlock(peers, peer);
250 goto next;
251 }
252
253 if (peer->max_fails
254 && peer->fails >= peer->max_fails
255 && now - peer->checked <= peer->fail_timeout)
256 {
257 ngx_http_upstream_rr_peer_unlock(peers, peer);
258 goto next;
259 }
260
261 if (peer->max_conns && peer->conns >= peer->max_conns) {
262 ngx_http_upstream_rr_peer_unlock(peers, peer);
263 goto next;
264 }
265
266 break;
267
268 next:
269
270 if (++rp->tries > 20) {
271 ngx_http_upstream_rr_peers_unlock(peers);
272 return ngx_http_upstream_get_round_robin_peer(pc, rrp);
273 }
274 }
275
276 rrp->current = peer;
277
278 if (now - peer->checked > peer->fail_timeout) {
279 peer->checked = now;
280 }
281
282 pc->sockaddr = peer->sockaddr;
283 pc->socklen = peer->socklen;
284 pc->name = &peer->name;
285
286 peer->conns++;
287
288 ngx_http_upstream_rr_peer_unlock(peers, peer);
289 ngx_http_upstream_rr_peers_unlock(peers);
290
291 rrp->tried[n] |= m;
292
293 return NGX_OK;
294 }
295
296
297 static ngx_int_t
298 ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc, void *data)
299 {
300 ngx_http_upstream_random_peer_data_t *rp = data;
301
302 time_t now;
303 uintptr_t m;
304 ngx_uint_t i, n, p;
305 ngx_http_upstream_rr_peer_t *peer, *prev;
306 ngx_http_upstream_rr_peers_t *peers;
307 ngx_http_upstream_rr_peer_data_t *rrp;
308
309 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
310 "get random2 peer, try: %ui", pc->tries);
311
312 rrp = &rp->rrp;
313 peers = rrp->peers;
314
315 ngx_http_upstream_rr_peers_wlock(peers);
316
317 if (rp->tries > 20 || peers->single) {
318 ngx_http_upstream_rr_peers_unlock(peers);
319 return ngx_http_upstream_get_round_robin_peer(pc, rrp);
320 }
321
322 pc->cached = 0;
323 pc->connection = NULL;
324
325 now = ngx_time();
326
327 prev = NULL;
328
329 #if (NGX_SUPPRESS_WARN)
330 p = 0;
331 #endif
332
333 for ( ;; ) {
334
335 i = ngx_http_upstream_peek_random_peer(peers, rp);
336
337 peer = rp->conf->ranges[i].peer;
338
339 if (peer == prev) {
340 goto next;
341 }
342
343 n = i / (8 * sizeof(uintptr_t));
344 m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
345
346 if (rrp->tried[n] & m) {
347 goto next;
348 }
349
350 if (peer->down) {
351 goto next;
352 }
353
354 if (peer->max_fails
355 && peer->fails >= peer->max_fails
356 && now - peer->checked <= peer->fail_timeout)
357 {
358 goto next;
359 }
360
361 if (peer->max_conns && peer->conns >= peer->max_conns) {
362 goto next;
363 }
364
365 if (prev) {
366 if (peer->conns * prev->weight > prev->conns * peer->weight) {
367 peer = prev;
368 n = p / (8 * sizeof(uintptr_t));
369 m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
370 }
371
372 break;
373 }
374
375 prev = peer;
376 p = i;
377
378 next:
379
380 if (++rp->tries > 20) {
381 ngx_http_upstream_rr_peers_unlock(peers);
382 return ngx_http_upstream_get_round_robin_peer(pc, rrp);
383 }
384 }
385
386 rrp->current = peer;
387
388 if (now - peer->checked > peer->fail_timeout) {
389 peer->checked = now;
390 }
391
392 pc->sockaddr = peer->sockaddr;
393 pc->socklen = peer->socklen;
394 pc->name = &peer->name;
395
396 peer->conns++;
397
398 ngx_http_upstream_rr_peers_unlock(peers);
399
400 rrp->tried[n] |= m;
401
402 return NGX_OK;
403 }
404
405
406 static ngx_uint_t
407 ngx_http_upstream_peek_random_peer(ngx_http_upstream_rr_peers_t *peers,
408 ngx_http_upstream_random_peer_data_t *rp)
409 {
410 ngx_uint_t i, j, k, x;
411
412 x = ngx_random() % peers->total_weight;
413
414 i = 0;
415 j = peers->number;
416
417 while (j - i > 1) {
418 k = (i + j) / 2;
419
420 if (x < rp->conf->ranges[k].range) {
421 j = k;
422
423 } else {
424 i = k;
425 }
426 }
427
428 return i;
429 }
430
431
432 static void *
433 ngx_http_upstream_random_create_conf(ngx_conf_t *cf)
434 {
435 ngx_http_upstream_random_srv_conf_t *conf;
436
437 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_random_srv_conf_t));
438 if (conf == NULL) {
439 return NULL;
440 }
441
442 /*
443 * set by ngx_pcalloc():
444 *
445 * conf->two = 0;
446 */
447
448 return conf;
449 }
450
451
452 static char *
453 ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
454 {
455 ngx_http_upstream_random_srv_conf_t *rcf = conf;
456
457 ngx_str_t *value;
458 ngx_http_upstream_srv_conf_t *uscf;
459
460 uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);
461
462 if (uscf->peer.init_upstream) {
463 ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
464 "load balancing method redefined");
465 }
466
467 uscf->peer.init_upstream = ngx_http_upstream_init_random;
468
469 uscf->flags = NGX_HTTP_UPSTREAM_CREATE
470 |NGX_HTTP_UPSTREAM_WEIGHT
471 |NGX_HTTP_UPSTREAM_MAX_CONNS
472 |NGX_HTTP_UPSTREAM_MAX_FAILS
473 |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
474 |NGX_HTTP_UPSTREAM_DOWN;
475
476 if (cf->args->nelts == 1) {
477 return NGX_CONF_OK;
478 }
479
480 value = cf->args->elts;
481
482 if (ngx_strcmp(value[1].data, "two") == 0) {
483 rcf->two = 1;
484
485 } else {
486 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
487 "invalid parameter \"%V\"", &value[1]);
488 return NGX_CONF_ERROR;
489 }
490
491 if (cf->args->nelts == 2) {
492 return NGX_CONF_OK;
493 }
494
495 if (ngx_strcmp(value[2].data, "least_conn") != 0) {
496 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
497 "invalid parameter \"%V\"", &value[2]);
498 return NGX_CONF_ERROR;
499 }
500
501 return NGX_CONF_OK;
502 }