| /* | |
| * Copyright (C) Maxim Dounin | |
| * Copyright (C) Nginx, Inc. | |
| */ | |
| #include <ngx_config.h> | |
| #include <ngx_core.h> | |
| #include <ngx_stream.h> | |
| static ngx_int_t ngx_stream_upstream_init_least_conn_peer( | |
| ngx_stream_session_t *s, ngx_stream_upstream_srv_conf_t *us); | |
| static ngx_int_t ngx_stream_upstream_get_least_conn_peer( | |
| ngx_peer_connection_t *pc, void *data); | |
| static char *ngx_stream_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, | |
| void *conf); | |
| static ngx_command_t ngx_stream_upstream_least_conn_commands[] = { | |
| { ngx_string("least_conn"), | |
| NGX_STREAM_UPS_CONF|NGX_CONF_NOARGS, | |
| ngx_stream_upstream_least_conn, | |
| 0, | |
| 0, | |
| NULL }, | |
| ngx_null_command | |
| }; | |
| static ngx_stream_module_t ngx_stream_upstream_least_conn_module_ctx = { | |
| NULL, /* preconfiguration */ | |
| NULL, /* postconfiguration */ | |
| NULL, /* create main configuration */ | |
| NULL, /* init main configuration */ | |
| NULL, /* create server configuration */ | |
| NULL /* merge server configuration */ | |
| }; | |
| ngx_module_t ngx_stream_upstream_least_conn_module = { | |
| NGX_MODULE_V1, | |
| &ngx_stream_upstream_least_conn_module_ctx, /* module context */ | |
| ngx_stream_upstream_least_conn_commands, /* module directives */ | |
| NGX_STREAM_MODULE, /* module type */ | |
| NULL, /* init master */ | |
| NULL, /* init module */ | |
| NULL, /* init process */ | |
| NULL, /* init thread */ | |
| NULL, /* exit thread */ | |
| NULL, /* exit process */ | |
| NULL, /* exit master */ | |
| NGX_MODULE_V1_PADDING | |
| }; | |
| static ngx_int_t | |
| ngx_stream_upstream_init_least_conn(ngx_conf_t *cf, | |
| ngx_stream_upstream_srv_conf_t *us) | |
| { | |
| ngx_log_debug0(NGX_LOG_DEBUG_STREAM, cf->log, 0, | |
| "init least conn"); | |
| if (ngx_stream_upstream_init_round_robin(cf, us) != NGX_OK) { | |
| return NGX_ERROR; | |
| } | |
| us->peer.init = ngx_stream_upstream_init_least_conn_peer; | |
| return NGX_OK; | |
| } | |
| static ngx_int_t | |
| ngx_stream_upstream_init_least_conn_peer(ngx_stream_session_t *s, | |
| ngx_stream_upstream_srv_conf_t *us) | |
| { | |
| ngx_log_debug0(NGX_LOG_DEBUG_STREAM, s->connection->log, 0, | |
| "init least conn peer"); | |
| if (ngx_stream_upstream_init_round_robin_peer(s, us) != NGX_OK) { | |
| return NGX_ERROR; | |
| } | |
| s->upstream->peer.get = ngx_stream_upstream_get_least_conn_peer; | |
| return NGX_OK; | |
| } | |
| static ngx_int_t | |
| ngx_stream_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data) | |
| { | |
| ngx_stream_upstream_rr_peer_data_t *rrp = data; | |
| time_t now; | |
| uintptr_t m; | |
| ngx_int_t rc, total; | |
| ngx_uint_t i, n, p, many; | |
| ngx_stream_upstream_rr_peer_t *peer, *best; | |
| ngx_stream_upstream_rr_peers_t *peers; | |
| ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0, | |
| "get least conn peer, try: %ui", pc->tries); | |
| if (rrp->peers->single) { | |
| return ngx_stream_upstream_get_round_robin_peer(pc, rrp); | |
| } | |
| pc->connection = NULL; | |
| now = ngx_time(); | |
| peers = rrp->peers; | |
| ngx_stream_upstream_rr_peers_wlock(peers); | |
| best = NULL; | |
| total = 0; | |
| #if (NGX_SUPPRESS_WARN) | |
| many = 0; | |
| p = 0; | |
| #endif | |
| for (peer = peers->peer, i = 0; | |
| peer; | |
| peer = peer->next, i++) | |
| { | |
| n = i / (8 * sizeof(uintptr_t)); | |
| m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); | |
| if (rrp->tried[n] & m) { | |
| continue; | |
| } | |
| if (peer->down) { | |
| continue; | |
| } | |
| if (peer->max_fails | |
| && peer->fails >= peer->max_fails | |
| && now - peer->checked <= peer->fail_timeout) | |
| { | |
| continue; | |
| } | |
| if (peer->max_conns && peer->conns >= peer->max_conns) { | |
| continue; | |
| } | |
| /* | |
| * select peer with least number of connections; if there are | |
| * multiple peers with the same number of connections, select | |
| * based on round-robin | |
| */ | |
| if (best == NULL | |
| || peer->conns * best->weight < best->conns * peer->weight) | |
| { | |
| best = peer; | |
| many = 0; | |
| p = i; | |
| } else if (peer->conns * best->weight == best->conns * peer->weight) { | |
| many = 1; | |
| } | |
| } | |
| if (best == NULL) { | |
| ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0, | |
| "get least conn peer, no peer found"); | |
| goto failed; | |
| } | |
| if (many) { | |
| ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0, | |
| "get least conn peer, many"); | |
| for (peer = best, i = p; | |
| peer; | |
| peer = peer->next, i++) | |
| { | |
| n = i / (8 * sizeof(uintptr_t)); | |
| m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); | |
| if (rrp->tried[n] & m) { | |
| continue; | |
| } | |
| if (peer->down) { | |
| continue; | |
| } | |
| if (peer->conns * best->weight != best->conns * peer->weight) { | |
| continue; | |
| } | |
| if (peer->max_fails | |
| && peer->fails >= peer->max_fails | |
| && now - peer->checked <= peer->fail_timeout) | |
| { | |
| continue; | |
| } | |
| if (peer->max_conns && peer->conns >= peer->max_conns) { | |
| continue; | |
| } | |
| peer->current_weight += peer->effective_weight; | |
| total += peer->effective_weight; | |
| if (peer->effective_weight < peer->weight) { | |
| peer->effective_weight++; | |
| } | |
| if (peer->current_weight > best->current_weight) { | |
| best = peer; | |
| p = i; | |
| } | |
| } | |
| } | |
| best->current_weight -= total; | |
| if (now - best->checked > best->fail_timeout) { | |
| best->checked = now; | |
| } | |
| pc->sockaddr = best->sockaddr; | |
| pc->socklen = best->socklen; | |
| pc->name = &best->name; | |
| best->conns++; | |
| rrp->current = best; | |
| n = p / (8 * sizeof(uintptr_t)); | |
| m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t)); | |
| rrp->tried[n] |= m; | |
| ngx_stream_upstream_rr_peers_unlock(peers); | |
| return NGX_OK; | |
| failed: | |
| if (peers->next) { | |
| ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0, | |
| "get least conn peer, backup servers"); | |
| rrp->peers = peers->next; | |
| n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1)) | |
| / (8 * sizeof(uintptr_t)); | |
| for (i = 0; i < n; i++) { | |
| rrp->tried[i] = 0; | |
| } | |
| ngx_stream_upstream_rr_peers_unlock(peers); | |
| rc = ngx_stream_upstream_get_least_conn_peer(pc, rrp); | |
| if (rc != NGX_BUSY) { | |
| return rc; | |
| } | |
| ngx_stream_upstream_rr_peers_wlock(peers); | |
| } | |
| ngx_stream_upstream_rr_peers_unlock(peers); | |
| pc->name = peers->name; | |
| return NGX_BUSY; | |
| } | |
| static char * | |
| ngx_stream_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) | |
| { | |
| ngx_stream_upstream_srv_conf_t *uscf; | |
| uscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_upstream_module); | |
| if (uscf->peer.init_upstream) { | |
| ngx_conf_log_error(NGX_LOG_WARN, cf, 0, | |
| "load balancing method redefined"); | |
| } | |
| uscf->peer.init_upstream = ngx_stream_upstream_init_least_conn; | |
| uscf->flags = NGX_STREAM_UPSTREAM_CREATE | |
| |NGX_STREAM_UPSTREAM_WEIGHT | |
| |NGX_STREAM_UPSTREAM_MAX_CONNS | |
| |NGX_STREAM_UPSTREAM_MAX_FAILS | |
| |NGX_STREAM_UPSTREAM_FAIL_TIMEOUT | |
| |NGX_STREAM_UPSTREAM_DOWN | |
| |NGX_STREAM_UPSTREAM_BACKUP; | |
| return NGX_CONF_OK; | |
| } |