Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_headers_filter_module.c @ 4667:d05ab8793a69 stable-1.2
Merge of r4622, r4623: balancing changes.
*) Upstream: smooth weighted round-robin balancing.
For edge case weights like { 5, 1, 1 } we now produce { a, a, b, a, c, a, a }
sequence instead of { c, b, a, a, a, a, a } produced previously.
Algorithm is as follows: on each peer selection we increase current_weight
of each eligible peer by its weight, select peer with greatest current_weight
and reduce its current_weight by total number of weight points distributed
among peers.
In case of { 5, 1, 1 } weights this gives the following sequence of
current_weight's:
a b c
0 0 0 (initial state)
5 1 1 (a selected)
-2 1 1
3 2 2 (a selected)
-4 2 2
1 3 3 (b selected)
1 -4 3
6 -3 4 (a selected)
-1 -3 4
4 -2 5 (c selected)
4 -2 -2
9 -1 -1 (a selected)
2 -1 -1
7 0 0 (a selected)
0 0 0
To preserve weight reduction in case of failures the effective_weight
variable was introduced, which usually matches peer's weight, but is
reduced temporarily on peer failures.
This change also fixes loop with backup servers and proxy_next_upstream
http_404 (ticket #47), and skipping alive upstreams in some cases if there
are multiple dead ones (ticket #64).
*) Upstream: fixed ip_hash rebalancing with the "down" flag.
Due to weight being set to 0 for down peers, order of peers after sorting
wasn't the same as without the "down" flag (with down peers at the end),
resulting in client rebalancing for clients on other servers. The only
rebalancing which should happen after adding "down" to a server is one
for clients on the server.
The problem was introduced in r1377 (which fixed endless loop by setting
weight to 0 for down servers). The loop is no longer possible with new
smooth algorithm, so preserving original weight is safe.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 04 Jun 2012 11:21:58 +0000 |
parents | 4c1e6cef1453 |
children | 3cb5cf1e1439 4c3c409ed306 |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #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_str_t key; ngx_http_set_header_pt handler; ngx_uint_t offset; }; typedef enum { NGX_HTTP_EXPIRES_OFF, NGX_HTTP_EXPIRES_EPOCH, NGX_HTTP_EXPIRES_MAX, NGX_HTTP_EXPIRES_ACCESS, NGX_HTTP_EXPIRES_MODIFIED, NGX_HTTP_EXPIRES_DAILY, NGX_HTTP_EXPIRES_UNSET } ngx_http_expires_t; typedef struct { ngx_http_expires_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_add_header(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_PARTIAL_CONTENT && r->headers_out.status != NGX_HTTP_MOVED_PERMANENTLY && r->headers_out.status != NGX_HTTP_MOVED_TEMPORARILY && r->headers_out.status != NGX_HTTP_SEE_OTHER && r->headers_out.status != NGX_HTTP_NOT_MODIFIED && r->headers_out.status != NGX_HTTP_TEMPORARY_REDIRECT)) { 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 && conf->expires != NGX_HTTP_EXPIRES_DAILY) { 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_DAILY) { expires_time = ngx_next_time(conf->expires_time); max_age = expires_time - now; } else 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 { 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 = 1; 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; old = (ngx_table_elt_t **) ((char *) &r->headers_out + hv->offset); r->headers_out.last_modified_time = -1; if (*old == NULL) { if (value->len == 0) { return NGX_OK; } h = ngx_list_push(&r->headers_out.headers); if (h == NULL) { return NGX_ERROR; } *old = h; } else { h = *old; if (value->len == 0) { h->hash = 0; return NGX_OK; } } h->hash = 1; 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_HTTP_EXPIRES_UNSET; 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_HTTP_EXPIRES_UNSET) { conf->expires = prev->expires; conf->expires_time = prev->expires_time; if (conf->expires == NGX_HTTP_EXPIRES_UNSET) { 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_HTTP_EXPIRES_UNSET) { 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 == (time_t) 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 (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->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; }