Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_upstream_random_module.c @ 7514:319242d2ddc9
Upstream: background cache update before cache send (ticket #1782).
In case of filter finalization, essential request fields like r->uri,
r->args etc could be changed, which affected the cache update subrequest.
Also, after filter finalization r->cache could be set to NULL, leading to
null pointer dereference in ngx_http_upstream_cache_background_update().
The fix is to create background cache update subrequest before sending the
cached response.
Since initial introduction in 1aeaae6e9446 (1.11.10) background cache update
subrequest was created after sending the cached response because otherwise it
blocked the parent request output. In 9552758a786e (1.13.1) background
subrequests were introduced to eliminate the delay before sending the final
part of the cached response. This also made it possible to create the
background cache update subrequest before sending the response.
Note that creating the subrequest earlier does not change the fact that in case
of filter finalization the background cache update subrequest will likely not
have enough time to successfully update the cache entry. Filter finalization
leads to the main request termination as soon the current iteration of request
processing is complete.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 03 Jun 2019 20:33:26 +0300 |
parents | f2396ecf608b |
children |
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/* * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_http_upstream_rr_peer_t *peer; ngx_uint_t range; } ngx_http_upstream_random_range_t; typedef struct { ngx_uint_t two; ngx_http_upstream_random_range_t *ranges; } ngx_http_upstream_random_srv_conf_t; typedef struct { /* the round robin data must be first */ ngx_http_upstream_rr_peer_data_t rrp; ngx_http_upstream_random_srv_conf_t *conf; u_char tries; } ngx_http_upstream_random_peer_data_t; static ngx_int_t ngx_http_upstream_init_random(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_update_random(ngx_pool_t *pool, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_init_random_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc, void *data); static ngx_int_t ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc, void *data); static ngx_uint_t ngx_http_upstream_peek_random_peer( ngx_http_upstream_rr_peers_t *peers, ngx_http_upstream_random_peer_data_t *rp); static void *ngx_http_upstream_random_create_conf(ngx_conf_t *cf); static char *ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_upstream_random_commands[] = { { ngx_string("random"), NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE12, ngx_http_upstream_random, NGX_HTTP_SRV_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_random_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_http_upstream_random_create_conf, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_upstream_random_module = { NGX_MODULE_V1, &ngx_http_upstream_random_module_ctx, /* module context */ ngx_http_upstream_random_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_random(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0, "init random"); if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { return NGX_ERROR; } us->peer.init = ngx_http_upstream_init_random_peer; #if (NGX_HTTP_UPSTREAM_ZONE) if (us->shm_zone) { return NGX_OK; } #endif return ngx_http_upstream_update_random(cf->pool, us); } static ngx_int_t ngx_http_upstream_update_random(ngx_pool_t *pool, ngx_http_upstream_srv_conf_t *us) { size_t size; ngx_uint_t i, total_weight; ngx_http_upstream_rr_peer_t *peer; ngx_http_upstream_rr_peers_t *peers; ngx_http_upstream_random_range_t *ranges; ngx_http_upstream_random_srv_conf_t *rcf; rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module); peers = us->peer.data; size = peers->number * sizeof(ngx_http_upstream_random_range_t); ranges = pool ? ngx_palloc(pool, size) : ngx_alloc(size, ngx_cycle->log); if (ranges == NULL) { return NGX_ERROR; } total_weight = 0; for (peer = peers->peer, i = 0; peer; peer = peer->next, i++) { ranges[i].peer = peer; ranges[i].range = total_weight; total_weight += peer->weight; } rcf->ranges = ranges; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_random_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { ngx_http_upstream_random_srv_conf_t *rcf; ngx_http_upstream_random_peer_data_t *rp; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "init random peer"); rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module); rp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_random_peer_data_t)); if (rp == NULL) { return NGX_ERROR; } r->upstream->peer.data = &rp->rrp; if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) { return NGX_ERROR; } if (rcf->two) { r->upstream->peer.get = ngx_http_upstream_get_random2_peer; } else { r->upstream->peer.get = ngx_http_upstream_get_random_peer; } rp->conf = rcf; rp->tries = 0; ngx_http_upstream_rr_peers_rlock(rp->rrp.peers); #if (NGX_HTTP_UPSTREAM_ZONE) if (rp->rrp.peers->shpool && rcf->ranges == NULL) { if (ngx_http_upstream_update_random(NULL, us) != NGX_OK) { ngx_http_upstream_rr_peers_unlock(rp->rrp.peers); return NGX_ERROR; } } #endif ngx_http_upstream_rr_peers_unlock(rp->rrp.peers); return NGX_OK; } static ngx_int_t ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_random_peer_data_t *rp = data; time_t now; uintptr_t m; ngx_uint_t i, n; ngx_http_upstream_rr_peer_t *peer; ngx_http_upstream_rr_peers_t *peers; ngx_http_upstream_rr_peer_data_t *rrp; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get random peer, try: %ui", pc->tries); rrp = &rp->rrp; peers = rrp->peers; ngx_http_upstream_rr_peers_rlock(peers); if (rp->tries > 20 || peers->single) { ngx_http_upstream_rr_peers_unlock(peers); return ngx_http_upstream_get_round_robin_peer(pc, rrp); } pc->cached = 0; pc->connection = NULL; now = ngx_time(); for ( ;; ) { i = ngx_http_upstream_peek_random_peer(peers, rp); peer = rp->conf->ranges[i].peer; n = i / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); if (rrp->tried[n] & m) { goto next; } ngx_http_upstream_rr_peer_lock(peers, peer); if (peer->down) { ngx_http_upstream_rr_peer_unlock(peers, peer); goto next; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { ngx_http_upstream_rr_peer_unlock(peers, peer); goto next; } if (peer->max_conns && peer->conns >= peer->max_conns) { ngx_http_upstream_rr_peer_unlock(peers, peer); goto next; } break; next: if (++rp->tries > 20) { ngx_http_upstream_rr_peers_unlock(peers); return ngx_http_upstream_get_round_robin_peer(pc, rrp); } } rrp->current = peer; if (now - peer->checked > peer->fail_timeout) { peer->checked = now; } pc->sockaddr = peer->sockaddr; pc->socklen = peer->socklen; pc->name = &peer->name; peer->conns++; ngx_http_upstream_rr_peer_unlock(peers, peer); ngx_http_upstream_rr_peers_unlock(peers); rrp->tried[n] |= m; return NGX_OK; } static ngx_int_t ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_random_peer_data_t *rp = data; time_t now; uintptr_t m; ngx_uint_t i, n, p; ngx_http_upstream_rr_peer_t *peer, *prev; ngx_http_upstream_rr_peers_t *peers; ngx_http_upstream_rr_peer_data_t *rrp; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get random2 peer, try: %ui", pc->tries); rrp = &rp->rrp; peers = rrp->peers; ngx_http_upstream_rr_peers_wlock(peers); if (rp->tries > 20 || peers->single) { ngx_http_upstream_rr_peers_unlock(peers); return ngx_http_upstream_get_round_robin_peer(pc, rrp); } pc->cached = 0; pc->connection = NULL; now = ngx_time(); prev = NULL; #if (NGX_SUPPRESS_WARN) p = 0; #endif for ( ;; ) { i = ngx_http_upstream_peek_random_peer(peers, rp); peer = rp->conf->ranges[i].peer; if (peer == prev) { goto next; } n = i / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); if (rrp->tried[n] & m) { goto next; } if (peer->down) { goto next; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { goto next; } if (peer->max_conns && peer->conns >= peer->max_conns) { goto next; } if (prev) { if (peer->conns * prev->weight > prev->conns * peer->weight) { peer = prev; n = p / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t)); } break; } prev = peer; p = i; next: if (++rp->tries > 20) { ngx_http_upstream_rr_peers_unlock(peers); return ngx_http_upstream_get_round_robin_peer(pc, rrp); } } rrp->current = peer; if (now - peer->checked > peer->fail_timeout) { peer->checked = now; } pc->sockaddr = peer->sockaddr; pc->socklen = peer->socklen; pc->name = &peer->name; peer->conns++; ngx_http_upstream_rr_peers_unlock(peers); rrp->tried[n] |= m; return NGX_OK; } static ngx_uint_t ngx_http_upstream_peek_random_peer(ngx_http_upstream_rr_peers_t *peers, ngx_http_upstream_random_peer_data_t *rp) { ngx_uint_t i, j, k, x; x = ngx_random() % peers->total_weight; i = 0; j = peers->number; while (j - i > 1) { k = (i + j) / 2; if (x < rp->conf->ranges[k].range) { j = k; } else { i = k; } } return i; } static void * ngx_http_upstream_random_create_conf(ngx_conf_t *cf) { ngx_http_upstream_random_srv_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_random_srv_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->two = 0; */ return conf; } static char * ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_upstream_random_srv_conf_t *rcf = conf; ngx_str_t *value; 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_random; 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; if (cf->args->nelts == 1) { return NGX_CONF_OK; } value = cf->args->elts; if (ngx_strcmp(value[1].data, "two") == 0) { rcf->two = 1; } else { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[1]); return NGX_CONF_ERROR; } if (cf->args->nelts == 2) { return NGX_CONF_OK; } if (ngx_strcmp(value[2].data, "least_conn") != 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[2]); return NGX_CONF_ERROR; } return NGX_CONF_OK; }