Mercurial > hg > nginx-quic
view src/http/ngx_http_variables.h @ 4621:c90801720a0c
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).
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 14 May 2012 09:57:20 +0000 |
parents | d620f497c50f |
children | a33b8c3aa975 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_HTTP_VARIABLES_H_INCLUDED_ #define _NGX_HTTP_VARIABLES_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef ngx_variable_value_t ngx_http_variable_value_t; #define ngx_http_variable(v) { sizeof(v) - 1, 1, 0, 0, 0, (u_char *) v } typedef struct ngx_http_variable_s ngx_http_variable_t; typedef void (*ngx_http_set_variable_pt) (ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); typedef ngx_int_t (*ngx_http_get_variable_pt) (ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); #define NGX_HTTP_VAR_CHANGEABLE 1 #define NGX_HTTP_VAR_NOCACHEABLE 2 #define NGX_HTTP_VAR_INDEXED 4 #define NGX_HTTP_VAR_NOHASH 8 struct ngx_http_variable_s { ngx_str_t name; /* must be first to build the hash */ ngx_http_set_variable_pt set_handler; ngx_http_get_variable_pt get_handler; uintptr_t data; ngx_uint_t flags; ngx_uint_t index; }; ngx_http_variable_t *ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags); ngx_int_t ngx_http_get_variable_index(ngx_conf_t *cf, ngx_str_t *name); ngx_http_variable_value_t *ngx_http_get_indexed_variable(ngx_http_request_t *r, ngx_uint_t index); ngx_http_variable_value_t *ngx_http_get_flushed_variable(ngx_http_request_t *r, ngx_uint_t index); ngx_http_variable_value_t *ngx_http_get_variable(ngx_http_request_t *r, ngx_str_t *name, ngx_uint_t key); ngx_int_t ngx_http_variable_unknown_header(ngx_http_variable_value_t *v, ngx_str_t *var, ngx_list_part_t *part, size_t prefix); #define ngx_http_clear_variable(r, index) r->variables0[index].text.data = NULL; #if (NGX_PCRE) typedef struct { ngx_uint_t capture; ngx_int_t index; } ngx_http_regex_variable_t; typedef struct { ngx_regex_t *regex; ngx_uint_t ncaptures; ngx_http_regex_variable_t *variables; ngx_uint_t nvariables; ngx_str_t name; } ngx_http_regex_t; typedef struct { ngx_http_regex_t *regex; void *value; } ngx_http_map_regex_t; ngx_http_regex_t *ngx_http_regex_compile(ngx_conf_t *cf, ngx_regex_compile_t *rc); ngx_int_t ngx_http_regex_exec(ngx_http_request_t *r, ngx_http_regex_t *re, ngx_str_t *s); #endif typedef struct { ngx_hash_combined_t hash; #if (NGX_PCRE) ngx_http_map_regex_t *regex; ngx_uint_t nregex; #endif } ngx_http_map_t; void *ngx_http_map_find(ngx_http_request_t *r, ngx_http_map_t *map, ngx_str_t *match); ngx_int_t ngx_http_variables_add_core_vars(ngx_conf_t *cf); ngx_int_t ngx_http_variables_init_vars(ngx_conf_t *cf); extern ngx_http_variable_value_t ngx_http_variable_null_value; extern ngx_http_variable_value_t ngx_http_variable_true_value; #endif /* _NGX_HTTP_VARIABLES_H_INCLUDED_ */