Mercurial > hg > nginx
view src/http/modules/ngx_http_headers_filter_module.c @ 4207:4fc91bae6f83
Better recheck of dead upstream servers.
Previously nginx used to mark backend again as live as soon as fail_timeout
passes (10s by default) since last failure. On the other hand, detecting
dead backend takes up to 60s (proxy_connect_timeout) in typical situation
"backend is down and doesn't respond to any packets". This resulted in
suboptimal behaviour in the above situation (up to 23% of requests were
directed to dead backend with default settings).
More detailed description of the problem may be found here (in Russian):
http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html
Fix is to only allow one request after fail_timeout passes, and
mark backend as "live" only if this request succeeds.
Note that with new code backend will not be marked "live" unless "check"
request is completed, and this may take a while in some specific workloads
(e.g. streaming). This is believed to be acceptable.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2011 14:22:48 +0000 |
parents | 59b99f217c6d |
children | ecf4608c2783 ea0f2e1f84d4 |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct ngx_http_header_val_s ngx_http_header_val_t; typedef ngx_int_t (*ngx_http_set_header_pt)(ngx_http_request_t *r, ngx_http_header_val_t *hv, ngx_str_t *value); typedef struct { ngx_str_t name; ngx_uint_t offset; ngx_http_set_header_pt handler; } ngx_http_set_header_t; struct ngx_http_header_val_s { ngx_http_complex_value_t value; ngx_uint_t hash; ngx_str_t key; ngx_http_set_header_pt handler; ngx_uint_t offset; }; #define NGX_HTTP_EXPIRES_OFF 0 #define NGX_HTTP_EXPIRES_EPOCH 1 #define NGX_HTTP_EXPIRES_MAX 2 #define NGX_HTTP_EXPIRES_ACCESS 3 #define NGX_HTTP_EXPIRES_MODIFIED 4 #define NGX_HTTP_EXPIRES_DAILY 5 typedef struct { ngx_uint_t expires; time_t expires_time; ngx_array_t *headers; } ngx_http_headers_conf_t; static ngx_int_t ngx_http_set_expires(ngx_http_request_t *r, ngx_http_headers_conf_t *conf); static ngx_int_t ngx_http_add_cache_control(ngx_http_request_t *r, ngx_http_header_val_t *hv, ngx_str_t *value); static ngx_int_t ngx_http_set_last_modified(ngx_http_request_t *r, ngx_http_header_val_t *hv, ngx_str_t *value); static void *ngx_http_headers_create_conf(ngx_conf_t *cf); static char *ngx_http_headers_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_headers_filter_init(ngx_conf_t *cf); static char *ngx_http_headers_expires(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_headers_add(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_http_set_header_t ngx_http_set_headers[] = { { ngx_string("Cache-Control"), 0, ngx_http_add_cache_control }, { ngx_string("Last-Modified"), offsetof(ngx_http_headers_out_t, last_modified), ngx_http_set_last_modified }, { ngx_null_string, 0, NULL } }; static ngx_command_t ngx_http_headers_filter_commands[] = { { ngx_string("expires"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF |NGX_CONF_TAKE12, ngx_http_headers_expires, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL}, { ngx_string("add_header"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF |NGX_CONF_TAKE2, ngx_http_headers_add, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL}, ngx_null_command }; static ngx_http_module_t ngx_http_headers_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_headers_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_headers_create_conf, /* create location configuration */ ngx_http_headers_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_headers_filter_module = { NGX_MODULE_V1, &ngx_http_headers_filter_module_ctx, /* module context */ ngx_http_headers_filter_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_http_output_header_filter_pt ngx_http_next_header_filter; static ngx_int_t ngx_http_headers_filter(ngx_http_request_t *r) { ngx_str_t value; ngx_uint_t i; ngx_http_header_val_t *h; ngx_http_headers_conf_t *conf; conf = ngx_http_get_module_loc_conf(r, ngx_http_headers_filter_module); if ((conf->expires == NGX_HTTP_EXPIRES_OFF && conf->headers == NULL) || r != r->main || (r->headers_out.status != NGX_HTTP_OK && r->headers_out.status != NGX_HTTP_NO_CONTENT && r->headers_out.status != NGX_HTTP_MOVED_PERMANENTLY && r->headers_out.status != NGX_HTTP_MOVED_TEMPORARILY && r->headers_out.status != NGX_HTTP_NOT_MODIFIED)) { return ngx_http_next_header_filter(r); } if (conf->expires != NGX_HTTP_EXPIRES_OFF) { if (ngx_http_set_expires(r, conf) != NGX_OK) { return NGX_ERROR; } } if (conf->headers) { h = conf->headers->elts; for (i = 0; i < conf->headers->nelts; i++) { if (ngx_http_complex_value(r, &h[i].value, &value) != NGX_OK) { return NGX_ERROR; } if (h[i].handler(r, &h[i], &value) != NGX_OK) { return NGX_ERROR; } } } return ngx_http_next_header_filter(r); } static ngx_int_t ngx_http_set_expires(ngx_http_request_t *r, ngx_http_headers_conf_t *conf) { size_t len; time_t now, expires_time, max_age; ngx_uint_t i; ngx_table_elt_t *expires, *cc, **ccp; expires = r->headers_out.expires; if (expires == NULL) { expires = ngx_list_push(&r->headers_out.headers); if (expires == NULL) { return NGX_ERROR; } r->headers_out.expires = expires; expires->hash = 1; ngx_str_set(&expires->key, "Expires"); } len = sizeof("Mon, 28 Sep 1970 06:00:00 GMT"); expires->value.len = len - 1; ccp = r->headers_out.cache_control.elts; if (ccp == NULL) { if (ngx_array_init(&r->headers_out.cache_control, r->pool, 1, sizeof(ngx_table_elt_t *)) != NGX_OK) { return NGX_ERROR; } ccp = ngx_array_push(&r->headers_out.cache_control); if (ccp == NULL) { return NGX_ERROR; } cc = ngx_list_push(&r->headers_out.headers); if (cc == NULL) { return NGX_ERROR; } cc->hash = 1; ngx_str_set(&cc->key, "Cache-Control"); *ccp = cc; } else { for (i = 1; i < r->headers_out.cache_control.nelts; i++) { ccp[i]->hash = 0; } cc = ccp[0]; } if (conf->expires == NGX_HTTP_EXPIRES_EPOCH) { expires->value.data = (u_char *) "Thu, 01 Jan 1970 00:00:01 GMT"; ngx_str_set(&cc->value, "no-cache"); return NGX_OK; } if (conf->expires == NGX_HTTP_EXPIRES_MAX) { expires->value.data = (u_char *) "Thu, 31 Dec 2037 23:55:55 GMT"; /* 10 years */ ngx_str_set(&cc->value, "max-age=315360000"); return NGX_OK; } expires->value.data = ngx_pnalloc(r->pool, len); if (expires->value.data == NULL) { return NGX_ERROR; } if (conf->expires_time == 0) { ngx_memcpy(expires->value.data, ngx_cached_http_time.data, ngx_cached_http_time.len + 1); ngx_str_set(&cc->value, "max-age=0"); return NGX_OK; } now = ngx_time(); if (conf->expires == NGX_HTTP_EXPIRES_ACCESS || r->headers_out.last_modified_time == -1) { expires_time = now + conf->expires_time; max_age = conf->expires_time; } else if (conf->expires == NGX_HTTP_EXPIRES_DAILY) { expires_time = ngx_next_time(conf->expires_time); max_age = expires_time - now; } else { expires_time = r->headers_out.last_modified_time + conf->expires_time; max_age = expires_time - now; } ngx_http_time(expires->value.data, expires_time); if (conf->expires_time < 0 || max_age < 0) { ngx_str_set(&cc->value, "no-cache"); return NGX_OK; } cc->value.data = ngx_pnalloc(r->pool, sizeof("max-age=") + NGX_TIME_T_LEN + 1); if (cc->value.data == NULL) { return NGX_ERROR; } cc->value.len = ngx_sprintf(cc->value.data, "max-age=%T", max_age) - cc->value.data; return NGX_OK; } static ngx_int_t ngx_http_add_header(ngx_http_request_t *r, ngx_http_header_val_t *hv, ngx_str_t *value) { ngx_table_elt_t *h; if (value->len) { h = ngx_list_push(&r->headers_out.headers); if (h == NULL) { return NGX_ERROR; } h->hash = hv->hash; h->key = hv->key; h->value = *value; } return NGX_OK; } static ngx_int_t ngx_http_add_cache_control(ngx_http_request_t *r, ngx_http_header_val_t *hv, ngx_str_t *value) { ngx_table_elt_t *cc, **ccp; ccp = r->headers_out.cache_control.elts; if (ccp == NULL) { if (ngx_array_init(&r->headers_out.cache_control, r->pool, 1, sizeof(ngx_table_elt_t *)) != NGX_OK) { return NGX_ERROR; } } ccp = ngx_array_push(&r->headers_out.cache_control); if (ccp == NULL) { return NGX_ERROR; } cc = ngx_list_push(&r->headers_out.headers); if (cc == NULL) { return NGX_ERROR; } cc->hash = 1; ngx_str_set(&cc->key, "Cache-Control"); cc->value = *value; *ccp = cc; return NGX_OK; } static ngx_int_t ngx_http_set_last_modified(ngx_http_request_t *r, ngx_http_header_val_t *hv, ngx_str_t *value) { ngx_table_elt_t *h, **old; if (hv->offset) { old = (ngx_table_elt_t **) ((char *) &r->headers_out + hv->offset); } else { old = NULL; } r->headers_out.last_modified_time = -1; if (old == NULL || *old == NULL) { if (value->len == 0) { return NGX_OK; } h = ngx_list_push(&r->headers_out.headers); if (h == NULL) { return NGX_ERROR; } } else { h = *old; if (value->len == 0) { h->hash = 0; return NGX_OK; } } h->hash = hv->hash; h->key = hv->key; h->value = *value; return NGX_OK; } static void * ngx_http_headers_create_conf(ngx_conf_t *cf) { ngx_http_headers_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_headers_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->headers = NULL; * conf->expires_time = 0; */ conf->expires = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_headers_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_headers_conf_t *prev = parent; ngx_http_headers_conf_t *conf = child; if (conf->expires == NGX_CONF_UNSET_UINT) { conf->expires = prev->expires; conf->expires_time = prev->expires_time; if (conf->expires == NGX_CONF_UNSET_UINT) { conf->expires = NGX_HTTP_EXPIRES_OFF; } } if (conf->headers == NULL) { conf->headers = prev->headers; } return NGX_CONF_OK; } static ngx_int_t ngx_http_headers_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_headers_filter; return NGX_OK; } static char * ngx_http_headers_expires(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_headers_conf_t *hcf = conf; ngx_uint_t minus, n; ngx_str_t *value; if (hcf->expires != NGX_CONF_UNSET_UINT) { return "is duplicate"; } value = cf->args->elts; if (cf->args->nelts == 2) { if (ngx_strcmp(value[1].data, "epoch") == 0) { hcf->expires = NGX_HTTP_EXPIRES_EPOCH; return NGX_CONF_OK; } if (ngx_strcmp(value[1].data, "max") == 0) { hcf->expires = NGX_HTTP_EXPIRES_MAX; return NGX_CONF_OK; } if (ngx_strcmp(value[1].data, "off") == 0) { hcf->expires = NGX_HTTP_EXPIRES_OFF; return NGX_CONF_OK; } hcf->expires = NGX_HTTP_EXPIRES_ACCESS; n = 1; } else { /* cf->args->nelts == 3 */ if (ngx_strcmp(value[1].data, "modified") != 0) { return "invalid value"; } hcf->expires = NGX_HTTP_EXPIRES_MODIFIED; n = 2; } if (value[n].data[0] == '@') { value[n].data++; value[n].len--; minus = 0; if (hcf->expires == NGX_HTTP_EXPIRES_MODIFIED) { return "daily time cannot be used with \"modified\" parameter"; } hcf->expires = NGX_HTTP_EXPIRES_DAILY; } else if (value[n].data[0] == '+') { value[n].data++; value[n].len--; minus = 0; } else if (value[n].data[0] == '-') { value[n].data++; value[n].len--; minus = 1; } else { minus = 0; } hcf->expires_time = ngx_parse_time(&value[n], 1); if (hcf->expires_time == NGX_ERROR) { return "invalid value"; } if (hcf->expires == NGX_HTTP_EXPIRES_DAILY && hcf->expires_time > 24 * 60 * 60) { return "daily time value must be less than 24 hours"; } if (hcf->expires_time == NGX_PARSE_LARGE_TIME) { return "value must be less than 68 years"; } if (minus) { hcf->expires_time = - hcf->expires_time; } return NGX_CONF_OK; } static char * ngx_http_headers_add(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_headers_conf_t *hcf = conf; ngx_str_t *value; ngx_uint_t i; ngx_http_header_val_t *hv; ngx_http_set_header_t *set; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; if (hcf->headers == NULL) { hcf->headers = ngx_array_create(cf->pool, 1, sizeof(ngx_http_header_val_t)); if (hcf->headers == NULL) { return NGX_CONF_ERROR; } } hv = ngx_array_push(hcf->headers); if (hv == NULL) { return NGX_CONF_ERROR; } hv->hash = 1; hv->key = value[1]; hv->handler = ngx_http_add_header; hv->offset = 0; set = ngx_http_set_headers; for (i = 0; set[i].name.len; i++) { if (ngx_strcasecmp(value[1].data, set[i].name.data) != 0) { continue; } hv->offset = set[i].offset; hv->handler = set[i].handler; break; } if (value[2].len == 0) { ngx_memzero(&hv->value, sizeof(ngx_http_complex_value_t)); return NGX_CONF_OK; } ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[2]; ccv.complex_value = &hv->value; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; }