view src/http/ngx_http_script.h @ 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 0a84dc5f5613
children d620f497c50f
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_HTTP_SCRIPT_H_INCLUDED_
#define _NGX_HTTP_SCRIPT_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef struct {
    u_char                     *ip;
    u_char                     *pos;
    ngx_http_variable_value_t  *sp;

    ngx_str_t                   buf;
    ngx_str_t                   line;

    /* the start of the rewritten arguments */
    u_char                     *args;

    unsigned                    flushed:1;
    unsigned                    skip:1;
    unsigned                    quote:1;
    unsigned                    is_args:1;
    unsigned                    log:1;

    ngx_int_t                   status;
    ngx_http_request_t         *request;
} ngx_http_script_engine_t;


typedef struct {
    ngx_conf_t                 *cf;
    ngx_str_t                  *source;

    ngx_array_t               **flushes;
    ngx_array_t               **lengths;
    ngx_array_t               **values;

    ngx_uint_t                  variables;
    ngx_uint_t                  ncaptures;
    ngx_uint_t                  captures_mask;
    ngx_uint_t                  size;

    void                       *main;

    unsigned                    compile_args:1;
    unsigned                    complete_lengths:1;
    unsigned                    complete_values:1;
    unsigned                    zero:1;
    unsigned                    conf_prefix:1;
    unsigned                    root_prefix:1;

    unsigned                    dup_capture:1;
    unsigned                    args:1;
} ngx_http_script_compile_t;


typedef struct {
    ngx_str_t                   value;
    ngx_uint_t                 *flushes;
    void                       *lengths;
    void                       *values;
} ngx_http_complex_value_t;


typedef struct {
    ngx_conf_t                 *cf;
    ngx_str_t                  *value;
    ngx_http_complex_value_t   *complex_value;

    unsigned                    zero:1;
    unsigned                    conf_prefix:1;
    unsigned                    root_prefix:1;
} ngx_http_compile_complex_value_t;


typedef void (*ngx_http_script_code_pt) (ngx_http_script_engine_t *e);
typedef size_t (*ngx_http_script_len_code_pt) (ngx_http_script_engine_t *e);


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   len;
} ngx_http_script_copy_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   index;
} ngx_http_script_var_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    ngx_http_set_variable_pt    handler;
    uintptr_t                   data;
} ngx_http_script_var_handler_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   n;
} ngx_http_script_copy_capture_code_t;


#if (NGX_PCRE)

typedef struct {
    ngx_http_script_code_pt     code;
    ngx_http_regex_t           *regex;
    ngx_array_t                *lengths;
    uintptr_t                   size;
    uintptr_t                   status;
    uintptr_t                   next;

    uintptr_t                   test:1;
    uintptr_t                   negative_test:1;
    uintptr_t                   uri:1;
    uintptr_t                   args:1;

    /* add the r->args to the new arguments */
    uintptr_t                   add_args:1;

    uintptr_t                   redirect:1;
    uintptr_t                   break_cycle:1;

    ngx_str_t                   name;
} ngx_http_script_regex_code_t;


typedef struct {
    ngx_http_script_code_pt     code;

    uintptr_t                   uri:1;
    uintptr_t                   args:1;

    /* add the r->args to the new arguments */
    uintptr_t                   add_args:1;

    uintptr_t                   redirect:1;
} ngx_http_script_regex_end_code_t;

#endif


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   conf_prefix;
} ngx_http_script_full_name_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   status;
    ngx_http_complex_value_t    text;
} ngx_http_script_return_code_t;


typedef enum {
    ngx_http_script_file_plain = 0,
    ngx_http_script_file_not_plain,
    ngx_http_script_file_dir,
    ngx_http_script_file_not_dir,
    ngx_http_script_file_exists,
    ngx_http_script_file_not_exists,
    ngx_http_script_file_exec,
    ngx_http_script_file_not_exec
} ngx_http_script_file_op_e;


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   op;
} ngx_http_script_file_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   next;
    void                      **loc_conf;
} ngx_http_script_if_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    ngx_array_t                *lengths;
} ngx_http_script_complex_value_code_t;


typedef struct {
    ngx_http_script_code_pt     code;
    uintptr_t                   value;
    uintptr_t                   text_len;
    uintptr_t                   text_data;
} ngx_http_script_value_code_t;


void ngx_http_script_flush_complex_value(ngx_http_request_t *r,
    ngx_http_complex_value_t *val);
ngx_int_t ngx_http_complex_value(ngx_http_request_t *r,
    ngx_http_complex_value_t *val, ngx_str_t *value);
ngx_int_t ngx_http_compile_complex_value(ngx_http_compile_complex_value_t *ccv);
char *ngx_http_set_complex_value_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


ngx_int_t ngx_http_test_predicates(ngx_http_request_t *r,
    ngx_array_t *predicates);
char *ngx_http_set_predicate_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);

ngx_uint_t ngx_http_script_variables_count(ngx_str_t *value);
ngx_int_t ngx_http_script_compile(ngx_http_script_compile_t *sc);
u_char *ngx_http_script_run(ngx_http_request_t *r, ngx_str_t *value,
    void *code_lengths, size_t reserved, void *code_values);
void ngx_http_script_flush_no_cacheable_variables(ngx_http_request_t *r,
    ngx_array_t *indices);

void *ngx_http_script_start_code(ngx_pool_t *pool, ngx_array_t **codes,
    size_t size);
void *ngx_http_script_add_code(ngx_array_t *codes, size_t size, void *code);

size_t ngx_http_script_copy_len_code(ngx_http_script_engine_t *e);
void ngx_http_script_copy_code(ngx_http_script_engine_t *e);
size_t ngx_http_script_copy_var_len_code(ngx_http_script_engine_t *e);
void ngx_http_script_copy_var_code(ngx_http_script_engine_t *e);
size_t ngx_http_script_copy_capture_len_code(ngx_http_script_engine_t *e);
void ngx_http_script_copy_capture_code(ngx_http_script_engine_t *e);
size_t ngx_http_script_mark_args_code(ngx_http_script_engine_t *e);
void ngx_http_script_start_args_code(ngx_http_script_engine_t *e);
#if (NGX_PCRE)
void ngx_http_script_regex_start_code(ngx_http_script_engine_t *e);
void ngx_http_script_regex_end_code(ngx_http_script_engine_t *e);
#endif
void ngx_http_script_return_code(ngx_http_script_engine_t *e);
void ngx_http_script_break_code(ngx_http_script_engine_t *e);
void ngx_http_script_if_code(ngx_http_script_engine_t *e);
void ngx_http_script_equal_code(ngx_http_script_engine_t *e);
void ngx_http_script_not_equal_code(ngx_http_script_engine_t *e);
void ngx_http_script_file_code(ngx_http_script_engine_t *e);
void ngx_http_script_complex_value_code(ngx_http_script_engine_t *e);
void ngx_http_script_value_code(ngx_http_script_engine_t *e);
void ngx_http_script_set_var_code(ngx_http_script_engine_t *e);
void ngx_http_script_var_set_handler_code(ngx_http_script_engine_t *e);
void ngx_http_script_var_code(ngx_http_script_engine_t *e);
void ngx_http_script_nop_code(ngx_http_script_engine_t *e);


#endif /* _NGX_HTTP_SCRIPT_H_INCLUDED_ */