view src/core/ngx_open_file_cache.h @ 4385:70ba81827472

Cache locks initial implementation. New directives: proxy_cache_lock on/off, proxy_cache_lock_timeout. With proxy_cache_lock set to on, only one request will be allowed to go to upstream for a particular cache item. Others will wait for a response to appear in cache (or cache lock released) up to proxy_cache_lock_timeout. Waiting requests will recheck if they have cached response ready (or are allowed to run) every 500ms. Note: we intentionally don't intercept NGX_DECLINED possibly returned by ngx_http_file_cache_read(). This needs more work (possibly safe, but needs further investigation). Anyway, it's exceptional situation. Note: probably there should be a way to disable caching of responses if there is already one request fetching resource to cache (without waiting at all). Two possible ways include another cache lock option ("no_cache") or using proxy_no_cache with some supplied variable. Note: probably there should be a way to lock updating requests as well. For now "proxy_cache_use_stale updating" is available.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 26 Dec 2011 11:15:23 +0000
parents e7cd13b7f759
children d620f497c50f
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 */


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


#ifndef _NGX_OPEN_FILE_CACHE_H_INCLUDED_
#define _NGX_OPEN_FILE_CACHE_H_INCLUDED_


#define NGX_OPEN_FILE_DIRECTIO_OFF  NGX_MAX_OFF_T_VALUE


typedef struct {
    ngx_fd_t                 fd;
    ngx_file_uniq_t          uniq;
    time_t                   mtime;
    off_t                    size;
    off_t                    fs_size;
    off_t                    directio;
    size_t                   read_ahead;

    ngx_err_t                err;
    char                    *failed;

    time_t                   valid;

    ngx_uint_t               min_uses;

    unsigned                 test_dir:1;
    unsigned                 test_only:1;
    unsigned                 log:1;
    unsigned                 errors:1;
    unsigned                 events:1;

    unsigned                 is_dir:1;
    unsigned                 is_file:1;
    unsigned                 is_link:1;
    unsigned                 is_exec:1;
    unsigned                 is_directio:1;
} ngx_open_file_info_t;


typedef struct ngx_cached_open_file_s  ngx_cached_open_file_t;

struct ngx_cached_open_file_s {
    ngx_rbtree_node_t        node;
    ngx_queue_t              queue;

    u_char                  *name;
    time_t                   created;
    time_t                   accessed;

    ngx_fd_t                 fd;
    ngx_file_uniq_t          uniq;
    time_t                   mtime;
    off_t                    size;
    ngx_err_t                err;

    uint32_t                 uses;

    unsigned                 count:24;
    unsigned                 close:1;
    unsigned                 use_event:1;

    unsigned                 is_dir:1;
    unsigned                 is_file:1;
    unsigned                 is_link:1;
    unsigned                 is_exec:1;
    unsigned                 is_directio:1;

    ngx_event_t             *event;
};


typedef struct {
    ngx_rbtree_t             rbtree;
    ngx_rbtree_node_t        sentinel;
    ngx_queue_t              expire_queue;

    ngx_uint_t               current;
    ngx_uint_t               max;
    time_t                   inactive;
} ngx_open_file_cache_t;


typedef struct {
    ngx_open_file_cache_t   *cache;
    ngx_cached_open_file_t  *file;
    ngx_uint_t               min_uses;
    ngx_log_t               *log;
} ngx_open_file_cache_cleanup_t;


typedef struct {

    /* ngx_connection_t stub to allow use c->fd as event ident */
    void                    *data;
    ngx_event_t             *read;
    ngx_event_t             *write;
    ngx_fd_t                 fd;

    ngx_cached_open_file_t  *file;
    ngx_open_file_cache_t   *cache;
} ngx_open_file_cache_event_t;


ngx_open_file_cache_t *ngx_open_file_cache_init(ngx_pool_t *pool,
    ngx_uint_t max, time_t inactive);
ngx_int_t ngx_open_cached_file(ngx_open_file_cache_t *cache, ngx_str_t *name,
    ngx_open_file_info_t *of, ngx_pool_t *pool);


#endif /* _NGX_OPEN_FILE_CACHE_H_INCLUDED_ */