PHP Redis disconnects and reconnects, pconnect connection fails
introduce
In swoole, workerman and other cli long connection modes, if Redis is abnormally disconnected and then opened later, you usually have to restart the program to use normally.
This article introduces the implementation of the original Redis disconnection without restarting the service.
principle
Called when Redis is disconnected
$Redis->ping()Will triggerNoticemistake，Notice: Redis::ping(): send of 14 bytes failed with errno=10054
When obtaining a redis instance, if the ping fails or an exception occurs, reconnect
Implement 1
Because try catch cannot catch notice exception, the ping is not connected directly, the catch catch catches the new connection instance is not connected, and the next time the ping is executed, the next time
Redis server went away abnormal
public static function getInstance( )
{
try {
if (!self::$_instance) {
new self();
} else {
if (!self::$_instance->ping())
new self();
}
} catch (\Exception $e) {
// Disconnect the wire and reconnect new self();
}
return self::$_instance;
}
Implement 2
1. Throw an notice exception before calling ping.
2. Call ping
3. Use error_get_last to get the last error. If the error message is the same as what we threw, it means that the ping is working. Otherwise, an exception will be thrown and the catch will catch the reconnection.
When you reconnect once and don't connect, you call $_instance->ping() again, you will directly throw a Redis server went away exception for catch to catch
public static function getInstance( )
{
if (!self::$_instance) {
new self();
}
else{
try {
@trigger_error('flag', E_USER_NOTICE);
self::$_instance->ping();
$error = error_get_last();
if($error['message'] != 'flag')
throw new \Exception('Redis server went away');
} catch (\Exception $e) {
// Disconnect the wire and reconnect new self();
}
}
return self::$_instance;
}
Redis class complete code
<?php
namespace lib;
class Redis
{
private static $_instance; //Storage objects private function __construct( ){
$config = Config::get('redis');
self::$_instance = new \Redis();
//Read from configuration self::$_instance->pconnect($config['host'], $config['port']);
if ('' != $config['password']) {
self::$_instance->auth($config['password']);
}
}
public static function getInstance( )
{
if (!self::$_instance) {
new self();
}
else{
try {
@trigger_error('flag', E_USER_NOTICE);
self::$_instance->ping();
$error = error_get_last();
if($error['message'] != 'flag')
throw new \Exception('Redis server went away');
} catch (\Exception $e) {
// Disconnect the wire and reconnect new self();
}
}
return self::$_instance;
}
// public static function getInstance( )
// {
// try {
// if (!self::$_instance) {
// new self();
// } else {
// if (!self::$_instance->ping())
// new self();
// }
// } catch (\Exception $e) {
// // Disconnect the wire and reconnect// new self();
// }
// return self::$_instance;
// }
/**
* Cloone is prohibited
*/
private function __clone(){}
/**
* Other methods are automatically called
* @param $method
* @param $args
* @return mixed
*/
public function __call($method,$args)
{
return call_user_func_array([self::$_instance, $method], $args);
}
/**
* Static call
* @param $method
* @param $args
* @return mixed
*/
public static function __callStatic($method,$args)
{
self::getInstance();
return call_user_func_array([self::$_instance, $method], $args);
}
}
Call
$this->handler = Redis::getInstance();
$key = $this->getCacheKey($name);
$value = $this->handler->get($key);
Replenish
pconnect failed to reconnect after establishing a connection
After testing the connection using pconnect to establish a connection under a long connection, redis timeout passively disconnected the link.
$res = self::$_instance->pconnect($config['host'], $config['port']);
$res will return true, but it is not a newly created link. Calling $res-get() will report an error
reason
Research findings
Using pconnect, the link is reused throughout the life cycle of the php process. The role of close is to make the current php no longer redis requests, but it cannot truly close the redis long connection. The connection will still be reused in subsequent requests until the end of the life cycle of the fpm process.
In a long connection, the connection will be disconnected only if the process is stopped. Therefore, when the connection is disconnected, new does not work, and the return connection is successful. In fact, it has been disconnected, and it is still the earliest connection, which cannot perform subsequent data reading operations.
So please use connect in long connection
This is the article about the case of short-term reconnection of PHP: Redis short-term reconnection. For more related content of PHP: Redis short-term reconnection, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!