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comparison src/http/modules/ngx_http_upstream_least_conn_module.c @ 676:bfa81a0490a2 NGINX_1_3_1

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nginx 1.3.1 *) Security: now nginx/Windows ignores trailing dot in URI path component, and does not allow URIs with ":$" in it. Thanks to Vladimir Kochetkov, Positive Research Center. *) Feature: the "proxy_pass", "fastcgi_pass", "scgi_pass", "uwsgi_pass" directives, and the "server" directive inside the "upstream" block, now support IPv6 addresses. *) Feature: the "resolver" directive now support IPv6 addresses and an optional port specification. *) Feature: the "least_conn" directive inside the "upstream" block. *) Feature: it is now possible to specify a weight for servers while using the "ip_hash" directive. *) Bugfix: a segmentation fault might occur in a worker process if the "image_filter" directive was used; the bug had appeared in 1.3.0. *) Bugfix: nginx could not be built with ngx_cpp_test_module; the bug had appeared in 1.1.12. *) Bugfix: access to variables from SSI and embedded perl module might not work after reconfiguration. Thanks to Yichun Zhang. *) Bugfix: in the ngx_http_xslt_filter_module. Thanks to Kuramoto Eiji. *) Bugfix: memory leak if $geoip_org variable was used. Thanks to Denis F. Latypoff. *) Bugfix: in the "proxy_cookie_domain" and "proxy_cookie_path" directives.
author Igor Sysoev <http://sysoev.ru>
date Tue, 05 Jun 2012 00:00:00 +0400
parents
children 5cb5db9975ba
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675:7052a9379344 676:bfa81a0490a2
1
2 /*
3 * Copyright (C) Maxim Dounin
4 * Copyright (C) Nginx, Inc.
5 */
6
7
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 #include <ngx_http.h>
11
12
13 typedef struct {
14 ngx_uint_t *conns;
15 } ngx_http_upstream_least_conn_conf_t;
16
17
18 typedef struct {
19 /* the round robin data must be first */
20 ngx_http_upstream_rr_peer_data_t rrp;
21
22 ngx_uint_t *conns;
23
24 ngx_event_get_peer_pt get_rr_peer;
25 ngx_event_free_peer_pt free_rr_peer;
26 } ngx_http_upstream_lc_peer_data_t;
27
28
29 static ngx_int_t ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r,
30 ngx_http_upstream_srv_conf_t *us);
31 static ngx_int_t ngx_http_upstream_get_least_conn_peer(
32 ngx_peer_connection_t *pc, void *data);
33 static void ngx_http_upstream_free_least_conn_peer(ngx_peer_connection_t *pc,
34 void *data, ngx_uint_t state);
35 static void *ngx_http_upstream_least_conn_create_conf(ngx_conf_t *cf);
36 static char *ngx_http_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd,
37 void *conf);
38
39
40 static ngx_command_t ngx_http_upstream_least_conn_commands[] = {
41
42 { ngx_string("least_conn"),
43 NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS,
44 ngx_http_upstream_least_conn,
45 0,
46 0,
47 NULL },
48
49 ngx_null_command
50 };
51
52
53 static ngx_http_module_t ngx_http_upstream_least_conn_module_ctx = {
54 NULL, /* preconfiguration */
55 NULL, /* postconfiguration */
56
57 NULL, /* create main configuration */
58 NULL, /* init main configuration */
59
60 ngx_http_upstream_least_conn_create_conf, /* create server configuration */
61 NULL, /* merge server configuration */
62
63 NULL, /* create location configuration */
64 NULL /* merge location configuration */
65 };
66
67
68 ngx_module_t ngx_http_upstream_least_conn_module = {
69 NGX_MODULE_V1,
70 &ngx_http_upstream_least_conn_module_ctx, /* module context */
71 ngx_http_upstream_least_conn_commands, /* module directives */
72 NGX_HTTP_MODULE, /* module type */
73 NULL, /* init master */
74 NULL, /* init module */
75 NULL, /* init process */
76 NULL, /* init thread */
77 NULL, /* exit thread */
78 NULL, /* exit process */
79 NULL, /* exit master */
80 NGX_MODULE_V1_PADDING
81 };
82
83
84 ngx_int_t
85 ngx_http_upstream_init_least_conn(ngx_conf_t *cf,
86 ngx_http_upstream_srv_conf_t *us)
87 {
88 ngx_uint_t n;
89 ngx_http_upstream_rr_peers_t *peers;
90 ngx_http_upstream_least_conn_conf_t *lcf;
91
92 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0,
93 "init least conn");
94
95 if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
96 return NGX_ERROR;
97 }
98
99 peers = us->peer.data;
100
101 n = peers->number;
102
103 if (peers->next) {
104 n += peers->next->number;
105 }
106
107 lcf = ngx_http_conf_upstream_srv_conf(us,
108 ngx_http_upstream_least_conn_module);
109
110 lcf->conns = ngx_pcalloc(cf->pool, sizeof(ngx_uint_t) * n);
111 if (lcf->conns == NULL) {
112 return NGX_ERROR;
113 }
114
115 us->peer.init = ngx_http_upstream_init_least_conn_peer;
116
117 return NGX_OK;
118 }
119
120
121 static ngx_int_t
122 ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r,
123 ngx_http_upstream_srv_conf_t *us)
124 {
125 ngx_http_upstream_lc_peer_data_t *lcp;
126 ngx_http_upstream_least_conn_conf_t *lcf;
127
128 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
129 "init least conn peer");
130
131 lcf = ngx_http_conf_upstream_srv_conf(us,
132 ngx_http_upstream_least_conn_module);
133
134 lcp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_lc_peer_data_t));
135 if (lcp == NULL) {
136 return NGX_ERROR;
137 }
138
139 lcp->conns = lcf->conns;
140
141 r->upstream->peer.data = &lcp->rrp;
142
143 if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
144 return NGX_ERROR;
145 }
146
147 r->upstream->peer.get = ngx_http_upstream_get_least_conn_peer;
148 r->upstream->peer.free = ngx_http_upstream_free_least_conn_peer;
149
150 lcp->get_rr_peer = ngx_http_upstream_get_round_robin_peer;
151 lcp->free_rr_peer = ngx_http_upstream_free_round_robin_peer;
152
153 return NGX_OK;
154 }
155
156
157 static ngx_int_t
158 ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
159 {
160 ngx_http_upstream_lc_peer_data_t *lcp = data;
161
162 time_t now;
163 uintptr_t m;
164 ngx_int_t rc, total;
165 ngx_uint_t i, n, p, many;
166 ngx_http_upstream_rr_peer_t *peer, *best;
167 ngx_http_upstream_rr_peers_t *peers;
168
169 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
170 "get least conn peer, try: %ui", pc->tries);
171
172 if (lcp->rrp.peers->single) {
173 return lcp->get_rr_peer(pc, &lcp->rrp);
174 }
175
176 pc->cached = 0;
177 pc->connection = NULL;
178
179 now = ngx_time();
180
181 peers = lcp->rrp.peers;
182
183 best = NULL;
184 total = 0;
185
186 #if (NGX_SUPPRESS_WARN)
187 many = 0;
188 p = 0;
189 #endif
190
191 for (i = 0; i < peers->number; i++) {
192
193 n = i / (8 * sizeof(uintptr_t));
194 m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
195
196 if (lcp->rrp.tried[n] & m) {
197 continue;
198 }
199
200 peer = &peers->peer[i];
201
202 if (peer->down) {
203 continue;
204 }
205
206 if (peer->max_fails
207 && peer->fails >= peer->max_fails
208 && now - peer->checked <= peer->fail_timeout)
209 {
210 continue;
211 }
212
213 /*
214 * select peer with least number of connections; if there are
215 * multiple peers with the same number of connections, select
216 * based on round-robin
217 */
218
219 if (best == NULL
220 || lcp->conns[i] * best->weight < lcp->conns[p] * peer->weight)
221 {
222 best = peer;
223 many = 0;
224 p = i;
225
226 } else if (lcp->conns[i] * best->weight
227 == lcp->conns[p] * peer->weight)
228 {
229 many = 1;
230 }
231 }
232
233 if (best == NULL) {
234 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0,
235 "get least conn peer, no peer found");
236
237 goto failed;
238 }
239
240 if (many) {
241 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0,
242 "get least conn peer, many");
243
244 for (i = p; i < peers->number; i++) {
245
246 n = i / (8 * sizeof(uintptr_t));
247 m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
248
249 if (lcp->rrp.tried[n] & m) {
250 continue;
251 }
252
253 peer = &peers->peer[i];
254
255 if (peer->down) {
256 continue;
257 }
258
259 if (lcp->conns[i] * best->weight != lcp->conns[p] * peer->weight) {
260 continue;
261 }
262
263 if (peer->max_fails
264 && peer->fails >= peer->max_fails
265 && now - peer->checked <= peer->fail_timeout)
266 {
267 continue;
268 }
269
270 peer->current_weight += peer->effective_weight;
271 total += peer->effective_weight;
272
273 if (peer->effective_weight < peer->weight) {
274 peer->effective_weight++;
275 }
276
277 if (peer->current_weight > best->current_weight) {
278 best = peer;
279 p = i;
280 }
281 }
282 }
283
284 best->current_weight -= total;
285 best->checked = now;
286
287 pc->sockaddr = best->sockaddr;
288 pc->socklen = best->socklen;
289 pc->name = &best->name;
290
291 lcp->rrp.current = p;
292
293 n = p / (8 * sizeof(uintptr_t));
294 m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
295
296 lcp->rrp.tried[n] |= m;
297 lcp->conns[p]++;
298
299 if (pc->tries == 1 && peers->next) {
300 pc->tries += peers->next->number;
301 }
302
303 return NGX_OK;
304
305 failed:
306
307 if (peers->next) {
308 ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0,
309 "get least conn peer, backup servers");
310
311 lcp->conns += peers->number;
312
313 lcp->rrp.peers = peers->next;
314 pc->tries = lcp->rrp.peers->number;
315
316 n = lcp->rrp.peers->number / (8 * sizeof(uintptr_t)) + 1;
317 for (i = 0; i < n; i++) {
318 lcp->rrp.tried[i] = 0;
319 }
320
321 rc = ngx_http_upstream_get_least_conn_peer(pc, lcp);
322
323 if (rc != NGX_BUSY) {
324 return rc;
325 }
326 }
327
328 /* all peers failed, mark them as live for quick recovery */
329
330 for (i = 0; i < peers->number; i++) {
331 peers->peer[i].fails = 0;
332 }
333
334 pc->name = peers->name;
335
336 return NGX_BUSY;
337 }
338
339
340 static void
341 ngx_http_upstream_free_least_conn_peer(ngx_peer_connection_t *pc,
342 void *data, ngx_uint_t state)
343 {
344 ngx_http_upstream_lc_peer_data_t *lcp = data;
345
346 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
347 "free least conn peer %ui %ui", pc->tries, state);
348
349 if (lcp->rrp.peers->single) {
350 lcp->free_rr_peer(pc, &lcp->rrp, state);
351 return;
352 }
353
354 if (state == 0 && pc->tries == 0) {
355 return;
356 }
357
358 lcp->conns[lcp->rrp.current]--;
359
360 lcp->free_rr_peer(pc, &lcp->rrp, state);
361 }
362
363
364 static void *
365 ngx_http_upstream_least_conn_create_conf(ngx_conf_t *cf)
366 {
367 ngx_http_upstream_least_conn_conf_t *conf;
368
369 conf = ngx_pcalloc(cf->pool,
370 sizeof(ngx_http_upstream_least_conn_conf_t));
371 if (conf == NULL) {
372 return NULL;
373 }
374
375 /*
376 * set by ngx_pcalloc():
377 *
378 * conf->conns = NULL;
379 */
380
381 return conf;
382 }
383
384
385 static char *
386 ngx_http_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
387 {
388 ngx_http_upstream_srv_conf_t *uscf;
389
390 uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);
391
392 uscf->peer.init_upstream = ngx_http_upstream_init_least_conn;
393
394 uscf->flags = NGX_HTTP_UPSTREAM_CREATE
395 |NGX_HTTP_UPSTREAM_WEIGHT
396 |NGX_HTTP_UPSTREAM_MAX_FAILS
397 |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
398 |NGX_HTTP_UPSTREAM_DOWN
399 |NGX_HTTP_UPSTREAM_BACKUP;
400
401 return NGX_CONF_OK;
402 }