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view src/core/ngx_times.h @ 8045:aa28c802409f

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Resolver: make TCP write timer event cancelable. Similar to 70e65bf8dfd7, the change is made to ensure that the ability to cancel resolver tasks is fully controlled by the caller. As mentioned in the referenced commit, it is safe to make this timer cancelable because resolve tasks can have their own timeouts that are not cancelable. The scenario where this may become a problem is a periodic background resolve task (not tied to a specific request or a client connection), which receives a response with short TTL, large enough to warrant fallback to a TCP query. With each event loop wakeup, we either have a previously set write timer instance or schedule a new one. The non-cancelable write timer can delay or block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable flag is set by the API user, and there are no other tasks or connections. We use the resolver API in this way to maintain the list of upstream server addresses specified with the 'resolve' parameter, and there could be third-party modules implementing similar logic.
author Aleksei Bavshin <a.bavshin@f5.com>
date Wed, 01 Jun 2022 20:17:23 -0700
parents 76e7e20cda05
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_TIMES_H_INCLUDED_
#define _NGX_TIMES_H_INCLUDED_


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


typedef struct {
    time_t      sec;
    ngx_uint_t  msec;
    ngx_int_t   gmtoff;
} ngx_time_t;


void ngx_time_init(void);
void ngx_time_update(void);
void ngx_time_sigsafe_update(void);
u_char *ngx_http_time(u_char *buf, time_t t);
u_char *ngx_http_cookie_time(u_char *buf, time_t t);
void ngx_gmtime(time_t t, ngx_tm_t *tp);

time_t ngx_next_time(time_t when);
#define ngx_next_time_n      "mktime()"


extern volatile ngx_time_t  *ngx_cached_time;

#define ngx_time()           ngx_cached_time->sec
#define ngx_timeofday()      (ngx_time_t *) ngx_cached_time

extern volatile ngx_str_t    ngx_cached_err_log_time;
extern volatile ngx_str_t    ngx_cached_http_time;
extern volatile ngx_str_t    ngx_cached_http_log_time;
extern volatile ngx_str_t    ngx_cached_http_log_iso8601;
extern volatile ngx_str_t    ngx_cached_syslog_time;

/*
 * milliseconds elapsed since some unspecified point in the past
 * and truncated to ngx_msec_t, used in event timers
 */
extern volatile ngx_msec_t  ngx_current_msec;


#endif /* _NGX_TIMES_H_INCLUDED_ */