# HG changeset patch # User Maxim Dounin # Date 1338765686 0 # Node ID a2ca3a6ee68087cc53381558c541a9ba385925e3 # Parent 134ccdf446473e008ae7b13d3ebe7b9b4540cb62 Upstream: least_conn balancer module. diff --git a/auto/modules b/auto/modules --- a/auto/modules +++ b/auto/modules @@ -345,6 +345,11 @@ if [ $HTTP_UPSTREAM_IP_HASH = YES ]; the HTTP_SRCS="$HTTP_SRCS $HTTP_UPSTREAM_IP_HASH_SRCS" fi +if [ $HTTP_UPSTREAM_LEAST_CONN = YES ]; then + HTTP_MODULES="$HTTP_MODULES $HTTP_UPSTREAM_LEAST_CONN_MODULE" + HTTP_SRCS="$HTTP_SRCS $HTTP_UPSTREAM_LEAST_CONN_SRCS" +fi + if [ $HTTP_UPSTREAM_KEEPALIVE = YES ]; then HTTP_MODULES="$HTTP_MODULES $HTTP_UPSTREAM_KEEPALIVE_MODULE" HTTP_SRCS="$HTTP_SRCS $HTTP_UPSTREAM_KEEPALIVE_SRCS" diff --git a/auto/options b/auto/options --- a/auto/options +++ b/auto/options @@ -96,6 +96,7 @@ HTTP_FLV=NO HTTP_MP4=NO HTTP_GZIP_STATIC=NO HTTP_UPSTREAM_IP_HASH=YES +HTTP_UPSTREAM_LEAST_CONN=YES HTTP_UPSTREAM_KEEPALIVE=YES # STUB @@ -243,6 +244,8 @@ use the \"--without-http_limit_conn_modu --without-http_empty_gif_module) HTTP_EMPTY_GIF=NO ;; --without-http_browser_module) HTTP_BROWSER=NO ;; --without-http_upstream_ip_hash_module) HTTP_UPSTREAM_IP_HASH=NO ;; + --without-http_upstream_least_conn_module) + HTTP_UPSTREAM_LEAST_CONN=NO ;; --without-http_upstream_keepalive_module) HTTP_UPSTREAM_KEEPALIVE=NO ;; --with-http_perl_module) HTTP_PERL=YES ;; diff --git a/auto/sources b/auto/sources --- a/auto/sources +++ b/auto/sources @@ -479,6 +479,11 @@ HTTP_UPSTREAM_IP_HASH_MODULE=ngx_http_up HTTP_UPSTREAM_IP_HASH_SRCS=src/http/modules/ngx_http_upstream_ip_hash_module.c +HTTP_UPSTREAM_LEAST_CONN_MODULE=ngx_http_upstream_least_conn_module +HTTP_UPSTREAM_LEAST_CONN_SRCS=" \ + src/http/modules/ngx_http_upstream_least_conn_module.c" + + HTTP_UPSTREAM_KEEPALIVE_MODULE=ngx_http_upstream_keepalive_module HTTP_UPSTREAM_KEEPALIVE_SRCS=" \ src/http/modules/ngx_http_upstream_keepalive_module.c" diff --git a/src/http/modules/ngx_http_upstream_least_conn_module.c b/src/http/modules/ngx_http_upstream_least_conn_module.c new file mode 100644 --- /dev/null +++ b/src/http/modules/ngx_http_upstream_least_conn_module.c @@ -0,0 +1,404 @@ + +/* + * Copyright (C) Maxim Dounin + * Copyright (C) Nginx, Inc. + */ + + +#include +#include +#include + + +typedef struct { + ngx_uint_t *conns; +} ngx_http_upstream_least_conn_conf_t; + + +typedef struct { + /* the round robin data must be first */ + ngx_http_upstream_rr_peer_data_t rrp; + + ngx_uint_t *conns; + + ngx_event_get_peer_pt get_rr_peer; + ngx_event_free_peer_pt free_rr_peer; +} ngx_http_upstream_lc_peer_data_t; + + +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 void ngx_http_upstream_free_least_conn_peer(ngx_peer_connection_t *pc, + void *data, ngx_uint_t state); +static void *ngx_http_upstream_least_conn_create_conf(ngx_conf_t *cf); +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 */ + + ngx_http_upstream_least_conn_create_conf, /* 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 +}; + + +ngx_int_t +ngx_http_upstream_init_least_conn(ngx_conf_t *cf, + ngx_http_upstream_srv_conf_t *us) +{ + ngx_uint_t n; + ngx_http_upstream_rr_peers_t *peers; + ngx_http_upstream_least_conn_conf_t *lcf; + + 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; + } + + peers = us->peer.data; + + n = peers->number; + + if (peers->next) { + n += peers->next->number; + } + + lcf = ngx_http_conf_upstream_srv_conf(us, + ngx_http_upstream_least_conn_module); + + lcf->conns = ngx_pcalloc(cf->pool, sizeof(ngx_uint_t) * n); + if (lcf->conns == NULL) { + 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_int_t rc; + ngx_http_upstream_lc_peer_data_t *lcp; + ngx_http_upstream_least_conn_conf_t *lcf; + + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, + "init least conn peer"); + + lcf = ngx_http_conf_upstream_srv_conf(us, + ngx_http_upstream_least_conn_module); + + lcp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_lc_peer_data_t)); + if (lcp == NULL) { + return NGX_ERROR; + } + + lcp->conns = lcf->conns; + + r->upstream->peer.data = &lcp->rrp; + + rc = ngx_http_upstream_init_round_robin_peer(r, us); + + 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; + r->upstream->peer.free = ngx_http_upstream_free_least_conn_peer; + + lcp->get_rr_peer = ngx_http_upstream_get_round_robin_peer; + lcp->free_rr_peer = ngx_http_upstream_free_round_robin_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_lc_peer_data_t *lcp = 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 (lcp->rrp.peers->single) { + return lcp->get_rr_peer(pc, &lcp->rrp); + } + + pc->cached = 0; + pc->connection = NULL; + + now = ngx_time(); + + peers = lcp->rrp.peers; + + best = NULL; + total = 0; + +#if (NGX_SUPPRESS_WARN) + many = 0; + p = 0; +#endif + + for (i = 0; i < peers->number; i++) { + + n = i / (8 * sizeof(uintptr_t)); + m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); + + if (lcp->rrp.tried[n] & m) { + continue; + } + + peer = &peers->peer[i]; + + if (peer->down) { + continue; + } + + if (peer->max_fails + && peer->fails >= peer->max_fails + && now - peer->checked <= peer->fail_timeout) + { + 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 + || lcp->conns[i] * best->weight < lcp->conns[p] * peer->weight) + { + best = peer; + many = 0; + p = i; + + } else if (lcp->conns[i] * best->weight + == lcp->conns[p] * 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 (i = p; i < peers->number; i++) { + + n = i / (8 * sizeof(uintptr_t)); + m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); + + if (lcp->rrp.tried[n] & m) { + continue; + } + + peer = &peers->peer[i]; + + if (peer->down) { + continue; + } + + if (lcp->conns[i] * best->weight != lcp->conns[p] * peer->weight) { + continue; + } + + if (peer->max_fails + && peer->fails >= peer->max_fails + && now - peer->checked <= peer->fail_timeout) + { + 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; + best->checked = now; + + pc->sockaddr = best->sockaddr; + pc->socklen = best->socklen; + pc->name = &best->name; + + lcp->rrp.current = p; + + n = p / (8 * sizeof(uintptr_t)); + m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t)); + + lcp->rrp.tried[n] |= m; + lcp->conns[p]++; + + if (pc->tries == 1 && peers->next) { + pc->tries += peers->next->number; + } + + return NGX_OK; + +failed: + + if (peers->next) { + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0, + "get least conn peer, backup servers"); + + lcp->conns += peers->number; + + lcp->rrp.peers = peers->next; + pc->tries = lcp->rrp.peers->number; + + n = lcp->rrp.peers->number / (8 * sizeof(uintptr_t)) + 1; + for (i = 0; i < n; i++) { + lcp->rrp.tried[i] = 0; + } + + rc = ngx_http_upstream_get_least_conn_peer(pc, lcp); + + if (rc != NGX_BUSY) { + return rc; + } + } + + /* all peers failed, mark them as live for quick recovery */ + + for (i = 0; i < peers->number; i++) { + peers->peer[i].fails = 0; + } + + pc->name = peers->name; + + return NGX_BUSY; +} + + +static void +ngx_http_upstream_free_least_conn_peer(ngx_peer_connection_t *pc, + void *data, ngx_uint_t state) +{ + ngx_http_upstream_lc_peer_data_t *lcp = data; + + ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, + "free least conn peer %ui %ui", pc->tries, state); + + if (lcp->rrp.peers->single) { + return lcp->free_rr_peer(pc, &lcp->rrp, state); + } + + if (state == 0 && pc->tries == 0) { + return; + } + + lcp->conns[lcp->rrp.current]--; + + return lcp->free_rr_peer(pc, &lcp->rrp, state); +} + + +static void * +ngx_http_upstream_least_conn_create_conf(ngx_conf_t *cf) +{ + ngx_http_upstream_least_conn_conf_t *conf; + + conf = ngx_pcalloc(cf->pool, + sizeof(ngx_http_upstream_least_conn_conf_t)); + if (conf == NULL) { + return NULL; + } + + /* + * set by ngx_pcalloc(): + * + * conf->conns = NULL; + */ + + return conf; +} + + +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); + + uscf->peer.init_upstream = ngx_http_upstream_init_least_conn; + + uscf->flags = NGX_HTTP_UPSTREAM_CREATE + |NGX_HTTP_UPSTREAM_WEIGHT + |NGX_HTTP_UPSTREAM_MAX_FAILS + |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT + |NGX_HTTP_UPSTREAM_DOWN + |NGX_HTTP_UPSTREAM_BACKUP; + + return NGX_CONF_OK; +}