add mysql pool demo

server/http_mysql_pool/Pool.php

@@ -0,0 +1,158 @@
+<?php
+
+/**
+ * author : rookiejin <mrjnamei@gmail.com>
+ * createTime : 2018/1/16 14:32
+ * description: Server.php - swoole-demo
+ */
+class Pool
+{
+    // 连接池数组 .
+    protected $connections ;
+
+    // 最大连接数
+    protected $max ;
+
+    // 最小连接数
+    protected $min ;
+
+    // 已连接数
+    protected $count = 0 ;
+
+    protected $inited = false ;
+
+    // 单例
+    private static $instance ;
+
+    //数据库配置
+    protected $config  = array(
+        'host' => '127.0.0.1',
+        'port' => 3306,
+        'user' => 'root',
+        'password' => 'rootpassword',
+        'database' => 'swoole',
+        'charset' => 'utf8',
+        'timeout' => 2,
+    );
+
+    public function __construct()
+    {
+        //初始化连接是一个Spl队列
+        $this->connections = new SplQueue() ;
+        $this->max = 30 ;
+        $this->min = 5 ;
+        // 绑定单例
+        self::$instance = & $this ;
+    }
+
+    // worker启动的时候 建立 min 个连接
+    public function init()
+    {
+        if($this->inited){
+            return ;
+        }
+        for($i = 0; $i < $this->min ; $i ++){
+            $this->generate();
+        }
+        return $this ;
+    }
+
+    /**
+     * 维持当前的连接数不断线，并且剔除断线的链接 .
+     */
+    public function keepAlive()
+    {
+        // 2分钟检测一次连接
+        swoole_timer_tick( 1000 , function(){
+            // 维持连接
+            while ($this->connections->count() >0 && $next=$this->connections->shift()){
+                $next->query("select 1" , function($db ,$res){
+                    if($res == false){
+                        return ;
+                    }
+                    echo "当前连接数：" . $this->connections->count() . PHP_EOL ;
+                    $this->connections->push($db);
+                });
+            }
+        });
+
+        swoole_timer_tick(1000 , function(){
+            // 维持活跃的链接数在 min-max之间
+            if($this->connections->count() > $this->max) {
+                while($this->max < $this->connections->count()){
+                    $next = $this->connections->shift();
+                    $next->close();
+                    $this->count -- ;
+                    echo "关闭连接...\n" ;
+                }
+            }
+        });
+    }
+
+    // 建立一个新的连接
+    public function generate($callback = null)
+    {
+        $db = new swoole_mysql ;
+        $db->connect($this->config , function($db , $res) use($callback) {
+            if($res == false){
+                throw new Exception("数据库连接错误::" . $db->connect_errno . $db->connect_error);
+            }
+            $this->count ++ ;
+            $this->addConnections($db);
+            if(is_callable($callback)){
+                call_user_func($callback);
+            }
+        });
+    }
+
+    // 连接推进队列
+    public function addConnections($db)
+    {
+        $this->connections->push($db);
+        return $this;
+    }
+
+    // 执行数据库命令 . 会判断连接数够不够，够就直接执行，不够就新建连接执行
+    public function query($query , $callback)
+    {
+        if($this->connections->count() == 0) {
+            $this->generate(function() use($query,$callback){
+                $this->exec($query,$callback);
+            });
+        }
+        else{
+           $this->exec($query,$callback);
+        }
+    }
+    // 直接执行数据库命令并且 callback();
+    private function exec($query, $callback)
+    {
+        $db = $this->connections->shift();
+        $db->query($query ,function($db , $result) use($callback){
+            $this->connections->push($db);
+            $callback($result);
+        });
+    }
+
+    public static function getInstance()
+    {
+        if(is_null(self::$instance)){
+            new Pool();
+        }
+        return self::$instance;
+    }
+}
+
+$server = new swoole_http_server("0.0.0.0",9501);
+$server->set([
+    'worker_num' => 1 ,
+]);
+$server->on("WorkerStart",function($server , $wid){
+    Pool::getInstance()->init()->keepAlive();
+});
+$server->on("request",function($request,$response){
+    $pool = Pool::getInstance()->query("select * from users", function($res) use($response) {
+        $response->end(json_encode($res));
+    });
+});
+$server->start();