nginx_upstream_hash-0.3.1.tar.gz

/* * Hash a variable to choose an upstream server. * * Copyright (C) Evan Miller * * This module can be distributed under the same terms as Nginx itself. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #define ngx_bitvector_index(index) index / (8 * sizeof(uintptr_t)) #define ngx_bitvector_bit(index) (uintptr_t) 1 << index % (8 * sizeof(uintptr_t)) typedef struct { struct sockaddr *sockaddr; socklen_t socklen; ngx_str_t name; } ngx_http_upstream_hash_peer_t; typedef struct { ngx_uint_t number; ngx_http_upstream_hash_peer_t peer[0]; } ngx_http_upstream_hash_peers_t; typedef struct { ngx_http_upstream_hash_peers_t *peers; ngx_uint_t hash; ngx_str_t current_key; ngx_str_t original_key; ngx_uint_t try_i; uintptr_t tried[1]; } ngx_http_upstream_hash_peer_data_t; static ngx_int_t ngx_http_upstream_init_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data); static void ngx_http_upstream_free_hash_peer(ngx_peer_connection_t *pc, void *data, ngx_uint_t state); static char *ngx_http_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_upstream_hash_again(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_int_t ngx_http_upstream_init_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); static ngx_uint_t ngx_http_upstream_hash_crc32(u_char *keydata, size_t keylen); static ngx_command_t ngx_http_upstream_hash_commands[] = { { ngx_string("hash"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE1, ngx_http_upstream_hash, 0, 0, NULL }, { ngx_string("hash_again"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE1, ngx_http_upstream_hash_again, 0, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_hash_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_hash_module = { NGX_MODULE_V1, &ngx_http_upstream_hash_module_ctx, /* module context */ ngx_http_upstream_hash_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_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { ngx_uint_t i, j, n; ngx_http_upstream_server_t *server; ngx_http_upstream_hash_peers_t *peers; us->peer.init = ngx_http_upstream_init_hash_peer; if (!us->servers) { return NGX_ERROR; } server = us->servers->elts; for (n = 0, i = 0; i < us->servers->nelts; i++) { n += server[i].naddrs; } peers = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_hash_peers_t) + sizeof(ngx_http_upstream_hash_peer_t) * n); if (peers == NULL) { return NGX_ERROR; } peers->number = n; /* one hostname can have multiple IP addresses in DNS */ for (n = 0, i = 0; i < us->servers->nelts; i++) { for (j = 0; j < server[i].naddrs; j++, n++) { peers->peer[n].sockaddr = server[i].addrs[j].sockaddr; peers->peer[n].socklen = server[i].addrs[j].socklen; peers->peer[n].name = server[i].addrs[j].name; } } us->peer.data = peers; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { ngx_http_upstream_hash_peer_data_t *uhpd; ngx_str_t val; if (ngx_http_script_run(r, &val, us->lengths, 0, us->values) == NULL) { return NGX_ERROR; } uhpd = ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_hash_peer_data_t) + sizeof(uintptr_t) * ((ngx_http_upstream_hash_peers_t *)us->peer.data)->number / (8 * sizeof(uintptr_t))); if (uhpd == NULL) { return NGX_ERROR; } r->upstream->peer.data = uhpd; uhpd->peers = us->peer.data; r->upstream->peer.free = ngx_http_upstream_free_hash_peer; r->upstream->peer.get = ngx_http_upstream_get_hash_peer; r->upstream->peer.tries = us->retries + 1; /* must be big enough for the retry keys */ if ((uhpd->current_key.data = ngx_pcalloc(r->pool, NGX_ATOMIC_T_LEN + val.len)) == NULL) { return NGX_ERROR; } ngx_memcpy(uhpd->current_key.data, val.data, val.len); uhpd->current_key.len = val.len; uhpd->original_key = val; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "upstream_hash: hashing \"%V\"", &val); uhpd->hash = ngx_http_upstream_hash_crc32(val.data, val.len); return NGX_OK; } static ngx_int_t ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_hash_peer_data_t *uhpd = data; ngx_http_upstream_hash_peer_t *peer; ngx_uint_t peer_index; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "upstream_hash: get upstream request hash peer try %ui", pc->tries); pc->cached = 0; pc->connection = NULL; peer_index = uhpd->hash % uhpd->peers->number; peer = &uhpd->peers->peer[peer_index]; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "upstream_hash: chose peer %ui w/ hash %ui", peer_index, uhpd->hash); pc->sockaddr = peer->sockaddr; pc->socklen = peer->socklen; pc->name = &peer->name; return NGX_OK; } /* retry implementation is PECL memcache compatible */ static void ngx_http_upstream_free_hash_peer(ngx_peer_connection_t *pc, void *data, ngx_uint_t state) { ngx_http_upstream_hash_peer_data_t *uhpd = data; ngx_uint_t current; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "upstream_hash: free upstream hash peer try %ui", pc->tries); if (state & (NGX_PEER_FAILED|NGX_PEER_NEXT) && --pc->tries) { current = uhpd->hash % uhpd->peers->number; uhpd->tried[ngx_bitvector_index(current)] |= ngx_bitvector_bit(current); do { uhpd->current_key.len = ngx_sprintf(uhpd->current_key.data, "%d%V", ++uhpd->try_i, &uhpd->original_key) - uhpd->current_key.data; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "upstream_hash: hashing \"%V\"", &uhpd->current_key); uhpd->hash += ngx_http_upstream_hash_crc32(uhpd->current_key.data, uhpd->current_key.len); current = uhpd->hash % uhpd->peers->number; } while ((uhpd->tried[ngx_bitvector_index(current)] & ngx_bitvector_bit(current)) && --pc->tries); } } /* bit-shift, bit-mask, and non-zero requirement are for l