黑夜路人：如何构建更健壮的在线系统

/*  简单容器底层机制实现模拟演示  说明：主要利用Linux的Namespace机制来实现，linux系统中unshare命令效果类似  Docker 调用机制是：Docker -> libcontainer(like lxc) -> cgroup -> namespace  Code by Black 2020.10.10*/#include <sys/types.h>#include <sys/wait.h>#include <linux/sched.h>#include <sched.h>#include <stdio.h>#include <signal.h>#include <unistd.h>#define STACK_SIZE (1024 * 1024)
static char container_stack[STACK_SIZE];char* const container_args[] = { "/bin/bash",  NULL };
//容器进行运行的程序主函数int container_main(void *args){    printf("容器进程开始. \n");    sethostname("black-container", 16);    //替换当前进程ps指令读取proc环节    system("mount -t proc proc /proc");    execv(container_args[0], container_args);}
int main(int args, char *argv[]){    printf("======Linux 容器功能简单实现 ======\n");    printf("======code by Black 2020.10 ======\n\n");    printf("正常主进程开始\n");    // clone 容器进程: hostname/消息通信/进程id 都独立 (CLONE_NEWUSER未实现)    int container_pid = clone(container_main, container_stack+STACK_SIZE,         SIGCHLD | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWNET, NULL);    // 等待容器进程结束    waitpid(container_pid, NULL, 0);    //恢复 /proc 下的内容    system("mount -t proc proc /proc");    printf("主要进程结束\n");    return 0;}

//程序里关键的日志都要记录（Debug/Notice/Warning/Error 等信息可以打印，warning/error 信息是一定要打印的SeasLog::debug('TRACE_ID:{traceId}; this is a {userName} debug',array('{traceId}'=>9527, '{userName}' => 'Black'));SeasLog::notice('TRACE_ID:{traceId}; this is a notice msg', array('{traceId}'=>9527));SeasLog::warning('TRACE_ID:{traceId}; this is a warning', array('{traceId}'=>9527));SeasLog::error('TRACE_ID:{traceId}; a error log', array('{traceId}'=>9527));

//获取一个整形的值 （使用else，共12行）function getIntValue($val) {    if ( $val != "" ) {    $ret = (int)$val;        if ($ret != 0 ) {            return $ret;        } else {            return false;        }    } else {        return false;    }}

//获取一个整形的值（不使用else，共10行）function getIntValue($val) {    if ( $val == "" ) {        return false;    }    $ret = (int)$val;    if ($ret == 0 ) {        return false;    }     return $ret;}

//Swoole 里通用超时设置（针对TCP协议情况，包含通用超时、连接超时、读写超时）Co::set([    'socket_timeout' => 5,    'socket_connect_timeout' => 1,    'socket_read_timeout' => 1,    'socket_write_timeout' => 1,]);
//Swoole 4.x协程方式访问MySQLCo\run(function () {    $swoole_mysql = new Swoole\Coroutine\MySQL();    $swoole_mysql->connect([        'host'     => '127.0.0.1',        'port'     => 3306,        'user'     => 'user',        'password' => 'pass',        'database' => 'test',        'timeout'     => '1',    ]);    $res = $swoole_mysql->query('select sleep(1)');    var_dump($res);});
//Swoole 4.x协程方式访问RedisCo\run(function () {    $redis = new Swoole\Coroutine\Redis();    $redis->setOptions(        'connect_timeout'    => '1',        'timeout'    => '1',    );    $redis->connect('127.0.0.1', 6379);    $val = $redis->get('key');});

function http_call($url)   $ch = curl_init($url);   curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);   //注意，毫秒超时一定要设置这个   curl_setopt($ch, CURLOPT_NOSIGNAL, 1);       //超时毫秒，cURL 7.16.2中被加入。从PHP 5.2.3起可使用   curl_setopt($ch, CURLOPT_TIMEOUT_MS, 200);     $data = curl_exec($ch);   $curl_errno = curl_errno($ch);  $curl_error = curl_error($ch);  curl_close($ch);}http_call('http://example.com')

<?php//自己定义读写超时常量if (!defined('MYSQL_OPT_READ_TIMEOUT')) define('MYSQL_OPT_READ_TIMEOUT',  11);if (!defined('MYSQL_OPT_WRITE_TIMEOUT')) define('MYSQL_OPT_WRITE_TIMEOUT', 12);
//设置超时$mysqli = mysqli_init();$mysqli->options(MYSQL_OPT_READ_TIMEOUT, 3); //读超时，没办法超过3秒$mysqli->options(MYSQL_OPT_WRITE_TIMEOUT, 1); //写超时，最小可设置为1秒
//连接数据库$mysqli->real_connect("localhost", "root", "root", "test");//执行查询 sleep 1秒不超时printf("Host information: %s/n", $mysqli->host_info);
//执行查询 sleep 1秒不超时printf("Host information: %s/n", $mysqli->host_info);if (!($res=$mysqli->query('select sleep(1)'))) {    echo "query1 error: ". $mysqli->error ."/n";} else {    echo "Query1: query success/n";}
//执行查询 sleep 9秒会超时，处理3秒超时情况，因为mysql自己会重试3次if (!($res=$mysqli->query('select sleep(9)'))) {    echo "query2 error: ". $mysqli->error ."/n";} else {    echo "Query2: query success/n";}
$mysqli->close();?>

// ## fsockopen访问HTTP ## $timeout = 5; //超时5秒$fp = fsockopen("example.com", 80, $errno, $errstr, $timeout); if ($fp) {         fwrite($fp, "GET / HTTP/1.0\r\n");         fwrite($fp, "Host: example.com\r\n");         fwrite($fp, "Connection: Close\r\n\r\n");         stream_set_blocking($fp, true);   //重要，设置为非阻塞模式        stream_set_timeout($fp,$timeout);   //设置超时        $info = stream_get_meta_data($fp);         while ((!feof($fp)) && (!$info['timed_out'])) {                 $data .= fgets($fp, 4096);                 $info = stream_get_meta_data($fp);                 ob_flush;                 flush();         }         if ($info['timed_out']) {                 echo "Connection Timed Out!";         }        else {                 echo $data;         } }

//fopen & file_get_contents 访问HTTP超时控制//设置超时和压入上下文环境$timeout = array(    'http' => array(        'timeout' => 5 //设置一个超时时间，单位为秒    ));$ctx = stream_context_create($timeout);//fopenif ($fp = fopen("http://example.com/", "r", false, $ctx)) {  while( $c = fread($fp, 8192)) {    echo $c;  }  fclose($fp);$text = file_get_contents("http://example.com/", 0, $ctx);echo $text;

SELECT uid,uname,email,gender FROM user WHERE uid = '9527'

SELECT uid,uname,email,gender FROM user WHERE uid = '9527' LIMIT 1

SELECT * FROM user WHERE uid = '9527'

SELECT uid,uname,email,gender FROM user WHERE uid = '9527' WHERE 1 LIMIT 1