A brief analysis of several timeout configurations in PHP configuration files-PHP Tutorial-php.cn

This article will talk about the PHP configuration file and analyze several timeout-related configurations in the configuration file (php.ini and php-fpm.conf). I hope it can help you!

A brief analysis of several timeout configurations in PHP configuration files

1. Overview

There are many timeout-related configurations in php.ini and php-fpm.conf, so what exactly do these configurations do? How is it implemented in the source code? This article will talk about the following timeout configurations:

php.ini

max_execution_time
max_input_time

php- fpm.conf

process_control_timeout
request_terminate_timeout
request_slowlog_timeout

##Running environment: Mac 10.14.2 PHP 7.3.7

2. Configure parsing rules

Parsing rules

The parsing of php.ini is completed in the

php_module_startup() stage, ini_entry is in The parsing rules defined for each php.ini configuration in main.c are in the following format:

ZEND_INI_ENTRY3_EX(name, default_value, modifiable, on_modify, arg1, arg2, arg3, displayer)

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PHP defines many macros for different types of configurations,

ZEND_INI_ENTRY3_EX is The final macro after they are expanded, such as PHP_INI_ENTRYMacro

PHP_INI_ENTRY(name, default_value, modifiable, on_modify)

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Parameter explanation

name: Configuration name

default_value: Configure the default value

modifiable: The configurable range of the configuration

These modes determine when and where a PHP command can be Whether it can be set. Each instruction in the manual has a mode to which it belongs. For example, some commands can be set in PHP scripts using ini_set(), while others can only be set in php.ini or httpd.conf.
For example, the output_buffering directive belongs to
PHP_INI_PERDIR, so it cannot be set with ini_set(). But the display_errors directive belongs to PHP_INI_ALL and can be set anywhere, including ini_set().
ModeMeaning##PHP_INI_USERPHP_INI_PERDIRPHP_INI_SYSTEMPHP_INI_ALL
on_modify： 配置修改函数
三、max_input_time、max_execution_time
因为max_input_time 和 max_execution_time 联系比较密切，所以放在一起来讲。
php.ini 解释

max_input_time

; Maximum amount of time each script may spend parsing request data. It's a good
; idea to limit this time on productions servers in order to eliminate unexpectedly
; long running scripts.
; Note: This directive is hardcoded to -1 for the CLI SAPI
; http://php.net/max-input-time

翻译过来就是：max_input_time是每个脚本可以花在解析请求数据上的最大时间。在生产服务器上通过限制max_input_time可以清除掉长时间运行的脚本。在CLI模式下会硬编码为-1，即无限制。

max_execution_time

; Maximum execution time of each script, in seconds
; http://php.net/max-execution-...
; Note: This directive is hardcoded to 0 for the CLI SAPI

翻译：max_execution_time是每个脚本的最大可执行时间。在CLI模式下硬编码为0

配置解析规则
// max_input_time，默认值为无限制
STD_PHP_INI_ENTRY("max_input_time", "-1",    PHP_INI_SYSTEM|PHP_INI_PERDIR, OnUpdateLong, max_input_time, php_core_globals, core_globals)
  
// max_execution_time，默认值为30s，修改函数为OnUpdateTimeout
PHP_INI_ENTRY("max_execution_time", "30",    PHP_INI_ALL, OnUpdateTimeout)
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OnUpdateTimeout()函数如下，由第二节可知配置解析发生在php_module_startup()阶段，此时EG(timeout_seconds)被赋值为了max_execution_time，但还没有设置定时器。
// main.c
static PHP_INI_MH(OnUpdateTimeout)
{
    if (stage==PHP_INI_STAGE_STARTUP) {
        /* Don&#39;t set a timeout on startup, only per-request */
    /* EG(timeout_seconds) = max_execution_time */
        ZEND_ATOL(EG(timeout_seconds), ZSTR_VAL(new_value));
        return SUCCESS;
    }
    zend_unset_timeout();
    ZEND_ATOL(EG(timeout_seconds), ZSTR_VAL(new_value));
    zend_set_timeout(EG(timeout_seconds), 0);
    return SUCCESS;
}
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设置超时定时器
// main.c
int php_request_startup(void) 
{
  ......
  if (PG(max_input_time) == -1) {
    zend_set_timeout(EG(timeout_seconds), 1);
  } else {
  zend_set_timeout(PG(max_input_time), 1);
  }
  ......
}

int php_execute_script(zend_file_handle *primary_file)
{
  ......
    if (PG(max_input_time) != -1) {
    zend_set_timeout(INI_INT("max_execution_time"), 0);
  }  
  ......
}
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从上面代码可以看到，如果设置了max_input_time（即值不等于-1，-1可以认为是在CLI模式下），在php_request_startup()阶段会设置一个定时器，超时时间为max_input_time；在php_execute_script()阶段会重新设置一个定时器，超时时间为max_execution_time。那么整个PHP脚本执行的最大执行时间就等于max_input_time + max_execution_time。
如果没有设置max_input_time的话（即值等于-1），在php_request_startup()阶段也会设置一个定时器，但超时时间被设为了EG(timeout_seconds)，而EG(timeout_seconds)已经在php_module_startup()阶段被赋值为max_execution_time，所以此时的超时时间就是max_execution_time；在php_execute_script()阶段不会重新设置定时器，前一阶段设置的max_execution_time定时器仍然生效着。那么整个PHP脚本的最大执行时间就是max_execution_time。
zend_set_time() 使用setitimer(ITIMER_PROF, &t_r, NULL); 来实现定时器，ITIMER_PROF会统计包括用户态和内核态下所花费的时间，而像sleep()这样的系统调用会让进程挂起，不占用cpu时间片，所以这俩超时时间是不包括sleep()时间的。
当定时器到时间后，ZendVM会抛出E_ERROR，即Fatal error错误。
四、process_control_timeout
php-fpm.conf 解释
; Time limit for child processes to wait for a reaction on signals from master.
; Available units: s(econds), m(inutes), h(ours), or d(ays)
; Default Unit: seconds
翻译：process_control_timeout是留给子进程处理来自master进程信号的时间限制。

分析
当master进程接收到SIGINT、SIGTERM、SIGQUIT、SIGUSR2这些信号时，会调用fpm_pctl()来进行处理。
首先master进程会根据接收到的信号和当前fpm的运行状态来决定发送给worker进程的是SIGQUIT还是SIGTERM信号，同时注册时间为process_control_timeout的定时事件。
如果在process_control_timeout时间内子进程没有退出，那么master进程会升级SIGQUIT为SIGTERM，SIGTERM为SIGKILL，并注册1s的定时事件。SIGKILL就直接终止worker进程了，SIGTERM还能再给worker进程1s的时间。
综上，process_control_timeout可以理解为master进程留给worker进程结束自己的时间，要是到时间worker还没搞定那就开始master自己的策略了。
五、request_terminate_timeout、request_slowlog_timeout
因为request_terminate_timeout 和 request_slowlog_timeout 联系比较密切，所以放在一起来讲。
php-fpm.conf Explanation

request_terminate_timeout

; The timeout for serving a single request after which the worker process will
; be killed. This option should be used when the 'max_execution_time' ini option
; does not stop script execution for some reason. A value of '0' means 'off'.
; Available units: s(econds)(default), m(inutes ), h(ours), or d(ays)
; Default Value: 0

Translation: The timeout period for executing a request, after which the worker process will be terminated. This option should be used when max_execution_time this ini option cannot stop script execution for some reason.

request_slowlog_timeout

; The timeout for serving a single request after which a PHP backtrace will be
; dumped to the 'slowlog' file. A value of '0s' means 'off' .
; Available units: s(econds)(default), m(inutes), h(ours), or d(ays)
; Default Value: 0

Translation: Execute a request timeout, after which a PHP backtrace will be output to the slowlog file.

Analysis
request_slowlog_timeout and request_terminate_timeout are used in the heartbeat detection of the master process (fpm_pctl_heartbeat()) , the heartbeat time heartbeat The simplified algorithm is

When request_terminate_timeout is turned on: request_terminate_timeout/1000*3

When request_terminate_timeout is not enabled: request_slowlog_timeout/1000*3 or 0

request_terminate_timeout >= request_slowlog_timeout

##The third rule is to ensure that slowlog does not affect normal requests,
heartbeat takes 1 of the timeout time /3 should be to avoid too frequent heartbeat detection, because each heartbeat detection needs to traverse all worker processes.
If a timeout event occurs, the worker process will be killed directly,
kill(child_pid, SIGTERM);, and then the kernel will recycle resources and close the client_socket, and nginx will return a 502 error to the browser.
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Can be set in a user script (e.g. ini_set()) or in the Windows registry (since PHP 5.3) and in .user.ini

Can be set in php.ini, .htaccess or httpd.conf

Can be set in php .ini or httpd.conf set

can be set anywhere


Can be set in a user script (e.g. ini_set()) or in the Windows registry (since PHP 5.3) and in .user.ini
Can be set in php.ini, .htaccess or httpd.conf
Can be set in php .ini or httpd.conf set
can be set anywhere

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