| |
| /* |
| * Copyright (C) Maxim Dounin |
| * Copyright (C) Nginx, Inc. |
| */ |
| |
| |
| #include <ngx_config.h> |
| #include <ngx_core.h> |
| #include <ngx_http.h> |
| |
| |
| static ngx_int_t ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r, |
| ngx_http_upstream_srv_conf_t *us); |
| static ngx_int_t ngx_http_upstream_get_least_conn_peer( |
| ngx_peer_connection_t *pc, void *data); |
| static char *ngx_http_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, |
| void *conf); |
| |
| |
| static ngx_command_t ngx_http_upstream_least_conn_commands[] = { |
| |
| { ngx_string("least_conn"), |
| NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS, |
| ngx_http_upstream_least_conn, |
| 0, |
| 0, |
| NULL }, |
| |
| ngx_null_command |
| }; |
| |
| |
| static ngx_http_module_t ngx_http_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 */ |
| |
| NULL, /* create location configuration */ |
| NULL /* merge location configuration */ |
| }; |
| |
| |
| ngx_module_t ngx_http_upstream_least_conn_module = { |
| NGX_MODULE_V1, |
| &ngx_http_upstream_least_conn_module_ctx, /* module context */ |
| ngx_http_upstream_least_conn_commands, /* module directives */ |
| NGX_HTTP_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_http_upstream_init_least_conn(ngx_conf_t *cf, |
| ngx_http_upstream_srv_conf_t *us) |
| { |
| ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0, |
| "init least conn"); |
| |
| if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { |
| return NGX_ERROR; |
| } |
| |
| us->peer.init = ngx_http_upstream_init_least_conn_peer; |
| |
| return NGX_OK; |
| } |
| |
| |
| static ngx_int_t |
| ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r, |
| ngx_http_upstream_srv_conf_t *us) |
| { |
| ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, |
| "init least conn peer"); |
| |
| if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) { |
| return NGX_ERROR; |
| } |
| |
| r->upstream->peer.get = ngx_http_upstream_get_least_conn_peer; |
| |
| return NGX_OK; |
| } |
| |
| |
| static ngx_int_t |
| ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data) |
| { |
| ngx_http_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_http_upstream_rr_peer_t *peer, *best; |
| ngx_http_upstream_rr_peers_t *peers; |
| |
| ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, |
| "get least conn peer, try: %ui", pc->tries); |
| |
| if (rrp->peers->single) { |
| return ngx_http_upstream_get_round_robin_peer(pc, rrp); |
| } |
| |
| pc->cached = 0; |
| pc->connection = NULL; |
| |
| now = ngx_time(); |
| |
| peers = rrp->peers; |
| |
| ngx_http_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_HTTP, pc->log, 0, |
| "get least conn peer, no peer found"); |
| |
| goto failed; |
| } |
| |
| if (many) { |
| ngx_log_debug0(NGX_LOG_DEBUG_HTTP, 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_http_upstream_rr_peers_unlock(peers); |
| |
| return NGX_OK; |
| |
| failed: |
| |
| if (peers->next) { |
| ngx_log_debug0(NGX_LOG_DEBUG_HTTP, 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_http_upstream_rr_peers_unlock(peers); |
| |
| rc = ngx_http_upstream_get_least_conn_peer(pc, rrp); |
| |
| if (rc != NGX_BUSY) { |
| return rc; |
| } |
| |
| ngx_http_upstream_rr_peers_wlock(peers); |
| } |
| |
| ngx_http_upstream_rr_peers_unlock(peers); |
| |
| pc->name = peers->name; |
| |
| return NGX_BUSY; |
| } |
| |
| |
| static char * |
| ngx_http_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) |
| { |
| ngx_http_upstream_srv_conf_t *uscf; |
| |
| uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_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_http_upstream_init_least_conn; |
| |
| uscf->flags = NGX_HTTP_UPSTREAM_CREATE |
| |NGX_HTTP_UPSTREAM_WEIGHT |
| |NGX_HTTP_UPSTREAM_MAX_CONNS |
| |NGX_HTTP_UPSTREAM_MAX_FAILS |
| |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT |
| |NGX_HTTP_UPSTREAM_DOWN |
| |NGX_HTTP_UPSTREAM_BACKUP; |
| |
| return NGX_CONF_OK; |
| } |
