view src/core/ngx_log.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 e27070fb6c6b
children f72496073689
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/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_LOG_H_INCLUDED_
#define _NGX_LOG_H_INCLUDED_


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


#define NGX_LOG_STDERR            0
#define NGX_LOG_EMERG             1
#define NGX_LOG_ALERT             2
#define NGX_LOG_CRIT              3
#define NGX_LOG_ERR               4
#define NGX_LOG_WARN              5
#define NGX_LOG_NOTICE            6
#define NGX_LOG_INFO              7
#define NGX_LOG_DEBUG             8

#define NGX_LOG_DEBUG_CORE        0x010
#define NGX_LOG_DEBUG_ALLOC       0x020
#define NGX_LOG_DEBUG_MUTEX       0x040
#define NGX_LOG_DEBUG_EVENT       0x080
#define NGX_LOG_DEBUG_HTTP        0x100
#define NGX_LOG_DEBUG_MAIL        0x200
#define NGX_LOG_DEBUG_MYSQL       0x400

/*
 * do not forget to update debug_levels[] in src/core/ngx_log.c
 * after the adding a new debug level
 */

#define NGX_LOG_DEBUG_FIRST       NGX_LOG_DEBUG_CORE
#define NGX_LOG_DEBUG_LAST        NGX_LOG_DEBUG_MYSQL
#define NGX_LOG_DEBUG_CONNECTION  0x80000000
#define NGX_LOG_DEBUG_ALL         0x7ffffff0


typedef u_char *(*ngx_log_handler_pt) (ngx_log_t *log, u_char *buf, size_t len);


struct ngx_log_s {
    ngx_uint_t           log_level;
    ngx_open_file_t     *file;

    ngx_atomic_uint_t    connection;

    ngx_log_handler_pt   handler;
    void                *data;

    /*
     * we declare "action" as "char *" because the actions are usually
     * the static strings and in the "u_char *" case we have to override
     * their types all the time
     */

    char                *action;
};


#define NGX_MAX_ERROR_STR   2048


/*********************************/

#if (NGX_HAVE_C99_VARIADIC_MACROS)

#define NGX_HAVE_VARIADIC_MACROS  1

#define ngx_log_error(level, log, ...)                                        \
    if ((log)->log_level >= level) ngx_log_error_core(level, log, __VA_ARGS__)

void ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, ...);

#define ngx_log_debug(level, log, ...)                                        \
    if ((log)->log_level & level)                                             \
        ngx_log_error_core(NGX_LOG_DEBUG, log, __VA_ARGS__)

/*********************************/

#elif (NGX_HAVE_GCC_VARIADIC_MACROS)

#define NGX_HAVE_VARIADIC_MACROS  1

#define ngx_log_error(level, log, args...)                                    \
    if ((log)->log_level >= level) ngx_log_error_core(level, log, args)

void ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, ...);

#define ngx_log_debug(level, log, args...)                                    \
    if ((log)->log_level & level)                                             \
        ngx_log_error_core(NGX_LOG_DEBUG, log, args)

/*********************************/

#else /* NO VARIADIC MACROS */

#define NGX_HAVE_VARIADIC_MACROS  0

void ngx_cdecl ngx_log_error(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, ...);
void ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, va_list args);
void ngx_cdecl ngx_log_debug_core(ngx_log_t *log, ngx_err_t err,
    const char *fmt, ...);


#endif /* VARIADIC MACROS */


/*********************************/

#if (NGX_DEBUG)

#if (NGX_HAVE_VARIADIC_MACROS)

#define ngx_log_debug0  ngx_log_debug
#define ngx_log_debug1  ngx_log_debug
#define ngx_log_debug2  ngx_log_debug
#define ngx_log_debug3  ngx_log_debug
#define ngx_log_debug4  ngx_log_debug
#define ngx_log_debug5  ngx_log_debug
#define ngx_log_debug6  ngx_log_debug
#define ngx_log_debug7  ngx_log_debug
#define ngx_log_debug8  ngx_log_debug


#else /* NO VARIADIC MACROS */

#define ngx_log_debug0(level, log, err, fmt)                                  \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt)

#define ngx_log_debug1(level, log, err, fmt, arg1)                            \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt, arg1)

#define ngx_log_debug2(level, log, err, fmt, arg1, arg2)                      \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt, arg1, arg2)

#define ngx_log_debug3(level, log, err, fmt, arg1, arg2, arg3)                \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3)

#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4)          \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4)

#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5)    \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4, arg5)

#define ngx_log_debug6(level, log, err, fmt,                                  \
                       arg1, arg2, arg3, arg4, arg5, arg6)                    \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4, arg5, arg6)

#define ngx_log_debug7(level, log, err, fmt,                                  \
                       arg1, arg2, arg3, arg4, arg5, arg6, arg7)              \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt,                                     \
                       arg1, arg2, arg3, arg4, arg5, arg6, arg7)

#define ngx_log_debug8(level, log, err, fmt,                                  \
                       arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)        \
    if ((log)->log_level & level)                                             \
        ngx_log_debug_core(log, err, fmt,                                     \
                       arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)

#endif

#else /* NO NGX_DEBUG */

#define ngx_log_debug0(level, log, err, fmt)
#define ngx_log_debug1(level, log, err, fmt, arg1)
#define ngx_log_debug2(level, log, err, fmt, arg1, arg2)
#define ngx_log_debug3(level, log, err, fmt, arg1, arg2, arg3)
#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4)
#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5)
#define ngx_log_debug6(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5, arg6)
#define ngx_log_debug7(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5,    \
                       arg6, arg7)
#define ngx_log_debug8(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5,    \
                       arg6, arg7, arg8)

#endif

/*********************************/

ngx_log_t *ngx_log_init(u_char *prefix);
ngx_log_t *ngx_log_create(ngx_cycle_t *cycle, ngx_str_t *name);
char *ngx_log_set_levels(ngx_conf_t *cf, ngx_log_t *log);
void ngx_cdecl ngx_log_abort(ngx_err_t err, const char *fmt, ...);
void ngx_cdecl ngx_log_stderr(ngx_err_t err, const char *fmt, ...);
u_char *ngx_log_errno(u_char *buf, u_char *last, ngx_err_t err);


extern ngx_module_t  ngx_errlog_module;
extern ngx_uint_t    ngx_use_stderr;


#endif /* _NGX_LOG_H_INCLUDED_ */