Swoole in action: How to use coroutines for caching operations

In recent years, Swoole, as a high-performance asynchronous network framework, has been favored by developers and is widely used in various fields. Coroutines are one of the very important concepts in using Swoole, which allow us to write asynchronous code in a synchronous manner. This article will introduce how to use coroutines for caching operations in Swoole and provide practical code examples.

1. What is a coroutine?

A coroutine is a lightweight thread in user mode. It is managed by programmers through code, avoiding the consumption and switching of system threads. In Swoole, coroutines can be used to solve I/O-intensive network operation problems, such as database connections, Redis operations, etc. The coroutine can proactively give up control when encountering an I/O operation and resume execution after the operation is completed.

2. Swoole’s coroutine support

Swoole has introduced coroutine support since version 1.8.0, which provides a series of APIs to implement coroutine scheduling, including coroutine, go, defer, channel, etc.

1. coroutine

Coroutine is the basic operation of coroutine. It allows us to convert a function into a coroutine, for example:

function test()
{
    echo "start
";
    Coroutine::sleep(1);
    echo "end
";
}

Coroutine::create('test');
echo "hello
";

In this example, We convert the test function into a coroutine and use Coroutine::create() to create a coroutine. In the coroutine, we use Coroutine::sleep() to simulate an I/O operation. This operation will cause the coroutine to pause for 1 second, then resume and continue to output "end". Finally, "hello" is output, which demonstrates the asynchronous nature of the coroutine.

2. go

go is a special function that allows us to run a function as a coroutine, for example:

go(function(){
    echo "hello
";
    Coroutine::sleep(1);
    echo "world
";
});
echo "start
";

In this example, we Use go() to run an anonymous function. In the function, we output "hello", pause for 1 second, and output "world" in sequence. Finally, "start" is output, which proves that we use coroutines to run this function concurrently.

3. defer

#defer allows us to perform some cleanup work at the end of the coroutine, such as closing database connections, releasing resources, etc. Its usage is as follows:

go(function(){
    $db = new Redis();
    $db->connect('127.0.0.1', 6379);
    defer(function() use ($db) {
        $db->close();
    });

    $db->set('key', 'value');
    Coroutine::sleep(1);
    $value = $db->get('key');
    echo $value."
";
});

In this example, we use defer to close the Redis connection at the end of the coroutine. If we do not use defer, we may forget to close the connection when the coroutine ends, causing the number of connections to be leaked.

4, channel

channel is a pipe-like mechanism provided by Swoole, which allows communication between multiple coroutines, for example:

$chan = new CoroutineChannel(1);

go(function() use($chan) {
    $data = Coroutine::getuid();
    $chan->push($data);
});

$data = $chan->pop();
echo $data."
";

In this In the example, we create a channel with a capacity of 1, then push a data to the channel in a coroutine, and pop the data in the channel in another coroutine and output it. Using channels allows us to transfer data between coroutines and complete collaborative task processing.

3. Coroutine operation cache

In actual development, cache is a very important component. It can reduce database pressure and speed up data reading through cache hits. In Swoole, we can use in-memory databases such as Redis to implement caching, and at the same time, we can use coroutines to improve the concurrency performance of the cache.

1. Connect to Redis

We use Swoole's coroutine Redis client to connect to the Redis database and perform operations concurrently. The code is as follows:

$redis = new SwooleCoroutineRedis();
$redis->connect('127.0.0.1', 6379);

go(function () use ($redis) {
    $redis->set('name', 'Bob');
    $name = $redis->get('name');
    echo "name=$name
";
});

go(function () use ($redis) {
    $redis->set('age', 18);
    $age = $redis->get('age');
    echo "age=$age
";
});

SwooleCoroutine::sleep(1);

In this example , we used Swoole's coroutine Redis client to connect to the Redis database. Then we performed reading and writing operations in the form of coroutines, and output the relevant results within the coroutines. Finally, use SwooleCoroutine::sleep() to wait for a period of time to ensure that the coroutine is completed. You can connect to and operate other in-memory databases in a similar manner.

2. Operation cache

After connecting to Redis, we can use a series of cache commands to operate. For example, to set cached data, you can use the set() method:

$redis->set('key', 'value');

where 'key' is the key of the cached data, and 'value' is the value of the cached data. To read cached data, you can use the get() method:

$value = $redis->get('key');

In the coroutine, we can use the above commands to operate concurrently. For example:

go(function() use($redis){
    $redis->set('key1', 'value1');
    $value1 = $redis->get('key1');
    echo "key1=$value1
";
});

go(function() use($redis){
    $redis->set('key2', 'value2');
    $value2 = $redis->get('key2');
    echo "key2=$value2
";
});

SwooleCoroutine::sleep(1);

In this example, we set and read two cached data in two coroutines respectively, and then performed the operations concurrently. This proves that coroutines can improve the concurrency performance of cached data.

3. Operation cache and MySQL

In practical applications, we usually need to combine cache and MySQL for operations. For example, read data from the cache first. If the cache does not exist, then read the data from the cache. Read in MySQL. In Swoole's coroutine development, we can use a method similar to the following to implement this operation:

$redis = new SwooleCoroutineRedis();
$redis->connect('127.0.0.1', 6379);

$mysql = new SwooleCoroutineMySQL();
$mysql->connect([
    'host' => '127.0.0.1',
    'port' => 3306,
    'user' => 'root',
    'password' => '123456',
    'database' => 'test',
]);

go(function() use($redis, $mysql) {
    $name = $redis->get('name');
    if($name === false) {
        $result = $mysql->query('select * from user where id=1');
        if(!empty($result)) {
            $name = $result[0]['name'];
            $redis->set('name', $name);
        }
    }
    echo "name=$name
";
});

go(function() use($redis, $mysql) {
    $age = $redis->get('age');
    if($age === false) {
        $result = $mysql->query('select * from user where id=1');
        if(!empty($result)) {
            $age = $result[0]['age'];
            $redis->set('age', $age);
        }
    }
    echo "age=$age
";
});

SwooleCoroutine::sleep(1);

In this example, we use the coroutine operation method, first try to read from the cache Get the data, if not in the cache, read the data from MySQL. When operating MySQL, we also use coroutines to avoid blocking threads and improve efficiency. Finally, we printed the read results to prove the correctness of this operation method.

The above is the specific implementation method of using coroutines for cache operations in Swoole. Coroutines can improve the efficiency and concurrency performance of cache operations, and can be combined with other operations such as MySQL. In actual development, we can practice in the above way and make adjustments and changes according to the actual situation.

The above is the detailed content of Swoole in action: How to use coroutines for caching operations. For more information, please follow other related articles on the PHP Chinese website!