2015-04-20 18:05:11 +08:00
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/*
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* Copyright (C) Maxim Dounin
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* Copyright (C) Nginx, Inc.
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*/
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#include <ngx_config.h>
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#include <ngx_core.h>
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#include <ngx_stream.h>
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static ngx_int_t ngx_stream_upstream_init_least_conn_peer(
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ngx_stream_session_t *s, ngx_stream_upstream_srv_conf_t *us);
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static ngx_int_t ngx_stream_upstream_get_least_conn_peer(
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ngx_peer_connection_t *pc, void *data);
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static char *ngx_stream_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd,
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void *conf);
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static ngx_command_t ngx_stream_upstream_least_conn_commands[] = {
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{ ngx_string("least_conn"),
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NGX_STREAM_UPS_CONF|NGX_CONF_NOARGS,
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ngx_stream_upstream_least_conn,
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0,
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0,
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NULL },
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ngx_null_command
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};
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static ngx_stream_module_t ngx_stream_upstream_least_conn_module_ctx = {
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2016-06-15 20:10:24 +08:00
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NULL, /* preconfiguration */
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2015-06-09 18:00:45 +08:00
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NULL, /* postconfiguration */
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2015-04-20 18:05:11 +08:00
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NULL, /* create main configuration */
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NULL, /* init main configuration */
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NULL, /* create server configuration */
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NULL, /* merge server configuration */
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};
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ngx_module_t ngx_stream_upstream_least_conn_module = {
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NGX_MODULE_V1,
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&ngx_stream_upstream_least_conn_module_ctx, /* module context */
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ngx_stream_upstream_least_conn_commands, /* module directives */
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NGX_STREAM_MODULE, /* module type */
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NULL, /* init master */
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NULL, /* init module */
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NULL, /* init process */
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NULL, /* init thread */
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NULL, /* exit thread */
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NULL, /* exit process */
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NULL, /* exit master */
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NGX_MODULE_V1_PADDING
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};
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static ngx_int_t
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ngx_stream_upstream_init_least_conn(ngx_conf_t *cf,
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ngx_stream_upstream_srv_conf_t *us)
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{
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ngx_log_debug0(NGX_LOG_DEBUG_STREAM, cf->log, 0,
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"init least conn");
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if (ngx_stream_upstream_init_round_robin(cf, us) != NGX_OK) {
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return NGX_ERROR;
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}
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us->peer.init = ngx_stream_upstream_init_least_conn_peer;
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return NGX_OK;
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}
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static ngx_int_t
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ngx_stream_upstream_init_least_conn_peer(ngx_stream_session_t *s,
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ngx_stream_upstream_srv_conf_t *us)
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{
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ngx_log_debug0(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
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"init least conn peer");
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if (ngx_stream_upstream_init_round_robin_peer(s, us) != NGX_OK) {
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return NGX_ERROR;
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}
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s->upstream->peer.get = ngx_stream_upstream_get_least_conn_peer;
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return NGX_OK;
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}
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static ngx_int_t
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ngx_stream_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
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{
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ngx_stream_upstream_rr_peer_data_t *rrp = data;
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time_t now;
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uintptr_t m;
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ngx_int_t rc, total;
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ngx_uint_t i, n, p, many;
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ngx_stream_upstream_rr_peer_t *peer, *best;
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ngx_stream_upstream_rr_peers_t *peers;
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ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
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"get least conn peer, try: %ui", pc->tries);
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if (rrp->peers->single) {
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return ngx_stream_upstream_get_round_robin_peer(pc, rrp);
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}
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pc->connection = NULL;
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now = ngx_time();
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peers = rrp->peers;
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ngx_stream_upstream_rr_peers_wlock(peers);
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best = NULL;
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total = 0;
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#if (NGX_SUPPRESS_WARN)
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many = 0;
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p = 0;
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#endif
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for (peer = peers->peer, i = 0;
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peer;
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peer = peer->next, i++)
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{
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n = i / (8 * sizeof(uintptr_t));
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m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
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if (rrp->tried[n] & m) {
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continue;
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}
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if (peer->down) {
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continue;
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}
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if (peer->max_fails
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&& peer->fails >= peer->max_fails
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&& now - peer->checked <= peer->fail_timeout)
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{
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continue;
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}
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/*
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* select peer with least number of connections; if there are
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* multiple peers with the same number of connections, select
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* based on round-robin
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*/
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if (best == NULL
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|| peer->conns * best->weight < best->conns * peer->weight)
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{
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best = peer;
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many = 0;
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p = i;
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} else if (peer->conns * best->weight == best->conns * peer->weight) {
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many = 1;
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}
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}
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if (best == NULL) {
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ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0,
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"get least conn peer, no peer found");
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goto failed;
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}
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if (many) {
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ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0,
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"get least conn peer, many");
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for (peer = best, i = p;
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peer;
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peer = peer->next, i++)
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{
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n = i / (8 * sizeof(uintptr_t));
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m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
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if (rrp->tried[n] & m) {
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continue;
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}
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if (peer->down) {
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continue;
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}
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if (peer->conns * best->weight != best->conns * peer->weight) {
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continue;
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}
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if (peer->max_fails
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&& peer->fails >= peer->max_fails
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&& now - peer->checked <= peer->fail_timeout)
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{
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continue;
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}
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peer->current_weight += peer->effective_weight;
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total += peer->effective_weight;
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if (peer->effective_weight < peer->weight) {
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peer->effective_weight++;
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}
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if (peer->current_weight > best->current_weight) {
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best = peer;
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p = i;
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}
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}
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}
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best->current_weight -= total;
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if (now - best->checked > best->fail_timeout) {
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best->checked = now;
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}
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pc->sockaddr = best->sockaddr;
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pc->socklen = best->socklen;
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pc->name = &best->name;
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best->conns++;
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rrp->current = best;
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n = p / (8 * sizeof(uintptr_t));
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m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
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rrp->tried[n] |= m;
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ngx_stream_upstream_rr_peers_unlock(peers);
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return NGX_OK;
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failed:
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if (peers->next) {
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ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0,
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"get least conn peer, backup servers");
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rrp->peers = peers->next;
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n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
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/ (8 * sizeof(uintptr_t));
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for (i = 0; i < n; i++) {
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2016-03-30 16:52:16 +08:00
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rrp->tried[i] = 0;
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2015-04-20 18:05:11 +08:00
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}
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ngx_stream_upstream_rr_peers_unlock(peers);
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rc = ngx_stream_upstream_get_least_conn_peer(pc, rrp);
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if (rc != NGX_BUSY) {
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return rc;
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}
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ngx_stream_upstream_rr_peers_wlock(peers);
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}
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/* all peers failed, mark them as live for quick recovery */
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for (peer = peers->peer; peer; peer = peer->next) {
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peer->fails = 0;
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}
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ngx_stream_upstream_rr_peers_unlock(peers);
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pc->name = peers->name;
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return NGX_BUSY;
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}
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static char *
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ngx_stream_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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{
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ngx_stream_upstream_srv_conf_t *uscf;
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uscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_upstream_module);
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if (uscf->peer.init_upstream) {
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ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
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"load balancing method redefined");
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}
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uscf->peer.init_upstream = ngx_stream_upstream_init_least_conn;
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uscf->flags = NGX_STREAM_UPSTREAM_CREATE
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|NGX_STREAM_UPSTREAM_WEIGHT
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|NGX_STREAM_UPSTREAM_MAX_FAILS
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|NGX_STREAM_UPSTREAM_FAIL_TIMEOUT
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|NGX_STREAM_UPSTREAM_DOWN
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|NGX_STREAM_UPSTREAM_BACKUP;
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return NGX_CONF_OK;
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}
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