Swooleによる高性能サーバー

Swooleとは

永続HTTPサーバー

<?php
$server = new Swoole\Http\Server('0.0.0.0', 9501);
$server->set(['worker_num' => 4]);

$server->on('request', function ($request, $response) {
    $response->header('Content-Type', 'application/json');
    $response->end(json_encode(['hello' => $request->server['request_uri']]));
});

echo "listening on :9501\n";
$server->start();

コールバックではなくコルーチン

<?php
use Swoole\Coroutine as Co;

Co\run(function () {
    go(function () { Co::sleep(1); echo "A done\n"; });
    go(function () { Co::sleep(1); echo "B done\n"; });
    // Both sleep concurrently -> total ~1s, not 2s
});

ブロッキング関数のフック

<?php
use Swoole\Runtime;
use Swoole\Coroutine as Co;

Runtime::enableCoroutine(SWOOLE_HOOK_ALL); // hook PDO, curl, sleep, etc.

Co\run(function () {
    go(function () { sleep(1); echo "task 1\n"; }); // sleep() is now async!
    go(function () { sleep(1); echo "task 2\n"; });
}); // finishes in ~1s because sleep was hooked

WaitGroupによる並行I/O

<?php
use Swoole\Coroutine as Co;
use Swoole\Coroutine\WaitGroup;

Co\run(function () {
    $wg = new WaitGroup();
    $results = [];
    foreach (['eu', 'us', 'asia'] as $region) {
        $wg->add();
        go(function () use ($wg, $region, &$results) {
            Co::sleep(0.5);              // simulated API call
            $results[$region] = "ok-$region";
            $wg->done();
        });
    }
    $wg->wait();                         // all three ran in parallel (~0.5s)
    var_dump($results);
});

通信用チャネル

<?php
use Swoole\Coroutine as Co;
use Swoole\Coroutine\Channel;

Co\run(function () {
    $chan = new Channel(2);
    go(function () use ($chan) {
        foreach (range(1, 3) as $n) $chan->push($n);
        $chan->push(null); // sentinel
    });
    go(function () use ($chan) {
        while (($v = $chan->pop()) !== null) echo "got $v\n";
    });
});

コネクションプーリング

<?php
use Swoole\Database\PDOConfig;
use Swoole\Database\PDOPool;
use Swoole\Coroutine as Co;

Co\run(function () {
    $pool = new PDOPool((new PDOConfig())
        ->withHost('127.0.0.1')->withDbname('app')
        ->withUsername('u')->withPassword('p'), 8);

    go(function () use ($pool) {
        $pdo = $pool->get();           // borrow
        $row = $pdo->query('SELECT NOW()')->fetch();
        $pool->put($pdo);              // return to pool
        var_dump($row);
    });
});

状態リーク：永続メモリの落とし穴

<?php
$server = new Swoole\Http\Server('0.0.0.0', 9501);
$server->set([
    'worker_num'  => 8,
    'max_request' => 10000, // recycle a worker after N requests to bound leaks
]);
// Never store $request data in a static property between requests!

コルーチンローカルコンテキスト

<?php
use Swoole\Coroutine as Co;

Co\run(function () {
    go(function () {
        $ctx = Co::getContext();
        $ctx['request_id'] = 'req-123';
        // ... deep call chain can read Co::getContext()['request_id']
        echo Co::getContext()['request_id'], PHP_EOL;
    });
});

プロセスモデルとタスクワーカー

Deferとタイマー

<?php
use Swoole\Coroutine as Co;

Co\run(function () {
    go(function () {
        $conn = 'borrowed-connection';
        Co::defer(function () use ($conn) {
            echo "released $conn\n"; // runs when coroutine exits, even on error
        });
        echo "using $conn\n";
    });
});

確認問題

まとめ