在 Yii 2 Starter Kit 中实现数据库连接时的动态配置，配置属性来源于多租户系统

1、多租户系统中包含多个租户，每个租户均有其自有的数据库配置信息，现有的需求是通过调用多租户系统的接口，基于响应的主机名、用户名和密码来连接数据库，而不是以应用组件的方式来配置，如图1

2、现在是以应用组件的方式来配置，\common\config\base.php，如图2

3、打开 Dubug，然后查看 Log Messages，db 组件的属性需要在 yii\db\Connection::open 之前完成初始化定义(调用多租户系统的接口)，如图3

4、编辑 \common\config\base.php，配置 db 组件的类：common\components\db\Connection，将所有 env 变量注释掉

        'db'=>[
            'class'=>'common\components\db\Connection',
            // 'dsn' => env('DB_DSN'),
            // 'username' => env('DB_USERNAME'),
            // 'password' => env('DB_PASSWORD'),
            // 'tablePrefix' => env('DB_TABLE_PREFIX'),
            'charset' => 'utf8',
            'enableSchemaCache' => YII_ENV_PROD,
        ],

5、新建 \common\components\db\Connection.php，继承至 \yii\db\Connection

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/01/15
 * Time: 16:18
 */

namespace common\components\db;

use Yii;
use yii\helpers\ArrayHelper;

/**
 * 获取租户模块环境配置信息，存储至Redis，注册db组件
 *
 * @author Qiang Wang <shuijingwanwq@163.com>
 * @since 1.0
 */

class Connection extends \yii\db\Connection
{
    public function __construct($config = [])
    {
        // ... 配置生效前的初始化过程
        $tenantConfig = [
            'dsn' => 'mysql:host=127.0.0.1;port=3306;dbname=cmcp-api',
            'username' => env('DB_USERNAME'),
            'password' => env('DB_PASSWORD'),
            'tablePrefix' => env('DB_TABLE_PREFIX'),
        ];

        if (!empty($config)) {
            $config = ArrayHelper::merge($config, $tenantConfig);
        }

        parent::__construct($config);
    }

}

6、重复第3步骤，db 组件的属性已经在 yii\db\Connection::open 之前完成初始化定义(host=localhost 变化为 host=127.0.0.1)，如图4

7、现在需要调用多租户系统的接口，以其响应重新赋值 $tenantConfig(建议：此方案仅适用于存在一个租户的情况，如果存在多个租户，建议每个租户对应不同的连接组件，连接组件的命名基于租户ID，而不是对应 db 连接组件)，如图5

8、现在还原所有修改，准备实现同时使用多个数据库(每个租户对应不同的连接组件，连接组件的命名基于租户ID)，参考网址：https://github.com/yiichina/yii2/blob/master/docs/guide-zh-CN/db-active-record.md ，如图6

9、新建 \common\components\db\ActiveRecord.php，继承至 \yii\db\ActiveRecord，重写 [[yii\db\ActiveRecord::getDb()|getDb()]] 方法

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/01/16
 * Time: 10:31
 */

namespace common\components\db;

use Yii;

/**
 * 获取租户模块环境配置信息，存储至Redis，注册数据库连接组件
 *
 * @author Qiang Wang <shuijingwanwq@163.com>
 * @since 1.0
 */

class ActiveRecord extends \yii\db\ActiveRecord
{
    /**
     * Returns the database connection used by this AR class.
     * By default, the "db" application component is used as the database connection.
     * You may override this method if you want to use a different database connection.
     * @return Connection the database connection used by this AR class.
     */
    public static function getDb()
    {
        $tenantDb = new \yii\db\Connection([
            'dsn' => 'mysql:host=127.0.0.1;port=3306;dbname=cmcp-api',
            'username' => env('DB_USERNAME'),
            'password' => env('DB_PASSWORD'),
            'tablePrefix' => env('DB_TABLE_PREFIX'),
            'charset' => 'utf8',
            'enableSchemaCache' => YII_ENV_PROD,
        ]);
        return $tenantDb;
        // return Yii::$app->getDb();
    }

}

10、编辑 \common\models\KeyStorageItem.php，继承至 common\components\db\ActiveRecord

<?php

namespace common\models;

use Yii;
use yii\behaviors\TimestampBehavior;
use common\components\db\ActiveRecord;

/**
 * This is the model class for table "key_storage_item".
 *
 * @property integer $key
 * @property integer $value
 */
class KeyStorageItem extends ActiveRecord
{
}

11、编辑 \common\config\base.php，注释掉 db 组件，后期建议将 db 组件移至开发环境，以方便于 Gii 的使用

        /*
        'db'=>[
            'class'=>'yii\db\Connection',
            'dsn' => env('DB_DSN'),
            'username' => env('DB_USERNAME'),
            'password' => env('DB_PASSWORD'),
            'tablePrefix' => env('DB_TABLE_PREFIX'),
            'charset' => 'utf8',
            'enableSchemaCache' => YII_ENV_PROD,
        ],
        */

12、打开：http://frontend.cmcp-api.localhost/ ，报错：Failed to instantiate component or class “db”.，原因在于日志目标为数据库表，如图7

13、查看日志组件配置，\common\config\base.php

        'log' => [
            'traceLevel' => YII_DEBUG ? 3 : 0,
            'targets' => [
                'db'=>[
                    'class' => 'yii\log\DbTarget',
                    'levels' => ['error', 'warning'],
                    'except'=>['yii\web\HttpException:*', 'yii\i18n\I18N\*'],
                    'prefix'=>function () {
                        $url = !Yii::$app->request->isConsoleRequest ? Yii::$app->request->getUrl() : null;
                        return sprintf('[%s][%s]', Yii::$app->id, $url);
                    },
                    'logVars'=>[],
                    'logTable'=>'{{%system_log}}'
                ]
            ],
        ],

14、日志组件必须在引导期间就被加载，因此如果数据库连接是动态配置的，已经晚于引导阶段了，编辑日志组件配置，\common\config\base.php，保存日志消息到文件中

        'log' => [
            'traceLevel' => YII_DEBUG ? 3 : 0,
            'targets' => [
                'file'=>[
                    'class' => 'yii\log\FileTarget',
                    'levels' => ['error', 'warning'],
                    'except' => ['yii\web\HttpException:*', 'yii\i18n\I18N\*'],
                    'prefix' => function () {
                        $url = !Yii::$app->request->isConsoleRequest ? Yii::$app->request->getUrl() : null;
                        return sprintf('[%s][%s]', Yii::$app->id, $url);
                    },
                    'logVars'=>[],
                ]
            ],
        ],

15、打开：http://frontend.cmcp-api.localhost/ ，报错：Unknown component ID: db，如图8

16、将 \common\models 下的所有模型文件，use yii\db\ActiveRecord; 替换为 use common\components\db\ActiveRecord;，如图9

use yii\db\ActiveRecord; 替换为 use common\components\db\ActiveRecord;
\yii\db\ActiveRecord 替换为 \common\components\db\ActiveRecord

17、打开：http://frontend.cmcp-api.localhost/ ，报错：Failed to instantiate component or class “db”.，原因在于 RBAC 组件使用数据库表存放数据，如图10

18、编辑 \common\config\base.php，注释掉 RBAC 组件，因为其 db 属性默认值为 db，需要动态调整为租户ID所对应的数据库连接组件

        /*
        'authManager' => [
            'class' => 'yii\rbac\DbManager',
            'itemTable' => '{{%rbac_auth_item}}',
            'itemChildTable' => '{{%rbac_auth_item_child}}',
            'assignmentTable' => '{{%rbac_auth_assignment}}',
            'ruleTable' => '{{%rbac_auth_rule}}'
        ],
        */

19、编辑 \common\components\db\ActiveRecord.php，通过 [[yii\di\ServiceLocator::setComponents()]] 方法注册数据库连接组件、RBAC组件

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/01/16
 * Time: 10:31
 */

namespace common\components\db;

use Yii;

/**
 * 获取租户模块环境配置信息，存储至Redis，注册数据库连接组件
 *
 * @author Qiang Wang <shuijingwanwq@163.com>
 * @since 1.0
 */

class ActiveRecord extends \yii\db\ActiveRecord
{
    /**
     * Returns the database connection used by this AR class.
     * By default, the "db" application component is used as the database connection.
     * You may override this method if you want to use a different database connection.
     * @return Connection the database connection used by this AR class.
     */
    public static function getDb()
    {
        $tenantDb = 'defaultDb';
        // 注册数据库连接组件、RBAC组件
        Yii::$app->setComponents([
            $tenantDb => [
                'class' => 'yii\db\Connection',
                'dsn' => 'mysql:host=127.0.0.1;port=3306;dbname=cmcp-api',
                'username' => env('DB_USERNAME'),
                'password' => env('DB_PASSWORD'),
                'tablePrefix' => env('DB_TABLE_PREFIX'),
                'charset' => 'utf8',
                'enableSchemaCache' => YII_ENV_PROD,
            ],
            'authManager' => [
                'class' => 'yii\rbac\DbManager',
                'db' => $tenantDb,
                'itemTable' => '{{%rbac_auth_item}}',
                'itemChildTable' => '{{%rbac_auth_item_child}}',
                'assignmentTable' => '{{%rbac_auth_assignment}}',
                'ruleTable' => '{{%rbac_auth_rule}}'
            ],
        ]);

        return Yii::$app->$tenantDb;
    }
}

20、重复第3步骤，db 组件的属性已经在 yii\db\Connection::open 之前完成初始化定义(host=localhost 变化为 host=127.0.0.1)，如图11

21、在 Postman 中，GET http://www.cmcp-api.localhost/v1/pages ，200响应，如图12

22、打开网址：http://backend.cmcp-api.localhost/ ，报错：Unknown component ID: db，如图13

23、编辑 \backend\models\SystemLog.php，继承至 \common\components\db\ActiveRecord，如图14

\yii\db\ActiveRecord 替换为 \common\components\db\ActiveRecord

24、打开网址：http://backend.cmcp-api.localhost/ ，200响应

25、现在需要调用多租户系统的接口，以其响应直接初始化使用数据库连接、RBAC，基于已经安装的 Yii 2 的 HTTP 客户端扩展，如图15

26、编辑 \.env.dist、\.env，新增多租户的相关配置

# 多租户
# ----
TENANT_HOST_INFO       = http://wjdev.chinamcloud.com:8600 # HOME URL
TENANT_BASE_URL        = /interface # BASE URL
TENANT_APP_NAME        = cmcpapi # 模块英文名称
TENANT_SECRET          = 94030d307b160f04b88592cb9bebdd4c # 模块Secret

27、编辑 \common\config\bootstrap.php，设置别名

Yii::setAlias('@tenantUrl', env('TENANT_HOST_INFO') . env('TENANT_BASE_URL'));

28、通过应用组件配置客户端，编辑 \common\config\web.php，如图16

        'tenantHttp' => [
            'class' => 'yii\httpclient\Client',
            'baseUrl' => Yii::getAlias('@tenantUrl'),
            'transport' => 'yii\httpclient\CurlTransport'
        ],

29、通过配置日志记录 HTTP 发送的请求并分析其执行情况，编辑 \common\config\base.php，如图17

                'httpRequest'=>[
                    'class' => 'yii\log\FileTarget',
                    'logFile' => '@runtime/logs/http-request.log',
                    'categories' => ['yii\httpclient\*'],
                ]

30、yii2 HTTP 客户端扩展提供了一个可以与 yii 调试模块集成的调试面板，并显示已执行的HTTP 请求，启用调试面板，如图18

    $config['modules']['debug'] = [
        'class' => 'yii\debug\Module',
        'allowedIPs' => ['127.0.0.1', '::1', '192.168.33.1', '172.17.42.1', '172.17.0.1', '192.168.99.1'],
        'panels' => [
            'httpclient' => [
                'class' => 'yii\httpclient\debug\HttpClientPanel',
            ],
        ],
    ];

31、刷新页面之后，查看日志面板，新增 HTTP Client，如图19

32、新建 \common\logics\http\tenant\Env.php，http目录表示此目录下的模型数据源自于HTTP请求，tenant目录表示多租户系统相关的模型，Env.php表示环境配置模型

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/01/17
 * Time: 15:20
 */

namespace common\logics\http\tenant;

use Yii;
use yii\base\Model;
use yii\web\ServerErrorHttpException;

/**
 * 多租户的模块环境配置
 *
 * @author Qiang Wang <shuijingwanwq@163.com>
 * @since 1.0
 */
class Env extends Model
{
    public $app_name;
    public $secret;
    public $tenant_id;

    public function attributeLabels()
    {
        return [
            'app_name' => \Yii::t('model/http/tenant/env', 'App Name'),
            'secret' => \Yii::t('model/http/tenant/env', 'Secret'),
            'tenant_id' => \Yii::t('model/http/tenant/env', 'Tenant ID'),
        ];
    }

    /**
     * 返回租户模块环境配置信息
     *
     * @return array|false
     *
     * 格式如下：
     *
     * 租户模块环境配置信息
     * [
     *     'message' => '', //说明
     *     'data' => [], //数据
     * ]
     *
     * 失败(将错误保存在 [[yii\base\Model::errors]] 属性中)
     * false
     *
     * @throws ServerErrorHttpException 如果响应状态码不等于20x
     */
    public function getTenantEnv()
    {
        $this->app_name = env('TENANT_APP_NAME');
        $this->secret = env('TENANT_SECRET');
        /* 租户ID后续从请求参数中获取 */
        $this->tenant_id = 'default';
        $response = Yii::$app->tenantHttp->createRequest()
            ->setMethod('get')
            ->setUrl('getTenantEnvs')
            ->setData([
                'appname' => $this->app_name,
                'secret' => $this->secret,
                'tenantid1' => $this->tenant_id,
            ])
            ->send();
        // 检查响应状态码是否等于20x
        if ($response->isOk) {
            // 检查业务逻辑是否成功
            if ($response->data['returnCode'] === 0) {
                return ['message' => $response->data['returnDesc'], 'data' => $response->data['returnData']];
            } else {
                $this->addError('tenant_id', $response->data['returnDesc']);
                return false;
            }
        } else {
            throw new ServerErrorHttpException(Yii::t('error', Yii::t('error', Yii::t('error', '20005'), ['statusCode' => $response->getStatusCode()])));
        }

    }

}

33、新建语言包文件，\common\messages\en\model\http\tenant\env.php、\common\messages\zh\model\http\tenant\env.php，如图20
\common\messages\en\model\http\tenant\env.php

return [
    'App Name' => 'English name of the module',
    'Secret' => 'Secret module in multi-tenant system',
    'Tenant ID' => 'Tenant ID',
];

\common\messages\zh\model\http\tenant\env.php

return [
    'App Name' => '模块英文名称',
    'Secret' => '模块Secret',
    'Tenant ID' => '租户ID',
];

34、编辑语言包文件，\api\messages\en\error.php、\api\messages\zh\error.php
\api\messages\en\error.php

    20005 => 'Multitenant HTTP request failed with status code: {statusCode}',
    20006 => 'Multitenant HTTP request failed: {firstErrors}',

\api\messages\zh\error.php

    20005 => '多租户HTTP请求失败，状态码：{statusCode}',
    20006 => '多租户HTTP请求失败：{firstErrors}',

35、复制 \api\messages\en\app.php、\api\messages\en\error.php、\api\messages\zh\app.php、\api\messages\zh\error.php 至 \common\messages\en\app.php、\common\messages\en\error.php、\common\messages\zh\app.php、\common\messages\zh\error.php，编辑
\common\messages\zh\error.php

return [
    20000 => 'error',
    20005 => '多租户HTTP请求失败，状态码：{statusCode}',
    20006 => '多租户HTTP请求失败：{firstErrors}',
];

36、编辑 \common\components\db\ActiveRecord.php，数据库配置信息源自于租户环境配置接口

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/01/16
 * Time: 10:31
 */

namespace common\components\db;

use Yii;
use common\logics\http\tenant\Env;
use yii\web\ServerErrorHttpException;

/**
 * 获取租户模块环境配置信息，存储至Redis，注册数据库连接组件
 *
 * @author Qiang Wang <shuijingwanwq@163.com>
 * @since 1.0
 */

class ActiveRecord extends \yii\db\ActiveRecord
{
    /**
     * Returns the database connection used by this AR class.
     * By default, the "db" application component is used as the database connection.
     * You may override this method if you want to use a different database connection.
     * @return Connection the database connection used by this AR class.
     */
    public static function getDb()
    {
        $env = new Env();
        $tenantEnv = $env->getTenantEnv();

        if ($tenantEnv === false) {
            if ($env->hasErrors()) {
                foreach ($env->getFirstErrors() as $message) {
                    $firstErrors = $message;
                }
                throw new ServerErrorHttpException(Yii::t('error', Yii::t('error', Yii::t('error', '20006'), ['firstErrors' => $firstErrors])));
            } elseif (!$env->hasErrors()) {
                throw new ServerErrorHttpException('Multi-tenant HTTP requests fail for unknown reasons.');
            }
        }

        $tenantDb = $tenantEnv['data']['tenantid'] . 'Db';
        // 注册数据库连接组件、RBAC组件
        Yii::$app->setComponents([
            $tenantDb => [
                'class' => 'yii\db\Connection',
                'dsn' => 'mysql:host=' .$tenantEnv['data']['db_info']['host'] . ';port=3306;dbname=' . $tenantEnv['data']['db_info']['database'] . '',
                'username' => $tenantEnv['data']['db_info']['login'],
                'password' => $tenantEnv['data']['db_info']['password'],
                'tablePrefix' => $tenantEnv['data']['db_info']['prefix'],
                'charset' => 'utf8',
                'enableSchemaCache' => YII_ENV_PROD,
            ],
            'authManager' => [
                'class' => 'yii\rbac\DbManager',
                'db' => $tenantDb,
                'itemTable' => '{{%rbac_auth_item}}',
                'itemChildTable' => '{{%rbac_auth_item_child}}',
                'assignmentTable' => '{{%rbac_auth_assignment}}',
                'ruleTable' => '{{%rbac_auth_rule}}'
            ],
        ]);
        
        return Yii::$app->$tenantDb;
    }
}

37、在 Postman 中 GET http://www.cmcp-api.localhost/v1/pages ，200响应，如图21

38、在 Postman 中 GET 多租户的环境配置接口，一个参数是错误的，如图22

39、编辑 \.env，TENANT_APP_NAME的值是错误的

TENANT_APP_NAME        = cmcpapi1 # 模块英文名称

40、在 Postman 中 GET http://www.cmcp-api.localhost/v1/pages ，500响应，如图23

41、查看日志，发现接口应用与后台应用分别请求多租户接口的次数为8、139次，后台报错：Unable to send log via yii\log\FileTarget: Exception (Database Exception) ‘yii\db\Exception’ with message ‘SQLSTATE[HY000] [1040] Too many connections’ ，如图24、25

42、检查数据库连接组件、RBAC组件是否被注册，如果已经被注册，则无需覆盖，编辑 \common\components\db\ActiveRecord.php，如图26

        // 检查数据库连接组件、RBAC组件是否被注册
        if (!(Yii::$app->has($tenantDb) && Yii::$app->has('authManager'))) {
            // 注册数据库连接组件、RBAC组件
            Yii::$app->setComponents([
                $tenantDb => [
                    'class' => 'yii\db\Connection',
                    'dsn' => 'mysql:host=' . $tenantEnv['data']['db_info']['host'] . ';port=3306;dbname=' . $tenantEnv['data']['db_info']['database'] . '',
                    'username' => $tenantEnv['data']['db_info']['login'],
                    'password' => $tenantEnv['data']['db_info']['password'],
                    'tablePrefix' => $tenantEnv['data']['db_info']['prefix'],
                    'charset' => 'utf8',
                    'enableSchemaCache' => YII_ENV_PROD,
                ],
                'authManager' => [
                    'class' => 'yii\rbac\DbManager',
                    'db' => $tenantDb,
                    'itemTable' => '{{%rbac_auth_item}}',
                    'itemChildTable' => '{{%rbac_auth_item_child}}',
                    'assignmentTable' => '{{%rbac_auth_assignment}}',
                    'ruleTable' => '{{%rbac_auth_rule}}'
                ],
            ]);
        }

43、后台应用报错：’SQLSTATE[HY000] [1040] Too many connections’ 已经解决，如图27

44、至此，数据库连接时的动态配置，配置属性来源于多租户系统已经基本上实现了，后续应该会实现缓存(多租户系统的响应)，因为一次请求中，对于多租户系统的HTTP请求多达上百次，而每次HTTP请求平均耗时为100ms左右，如图28

45、开启 Schema 缓存(仅在生产环境中开启)，且缓存至 Redis 中，编辑 \.env.dist、\.env，如图29

YII_ENV     = prod

# Redis
# ----
REDIS_HOSTNAME         = localhost # 主机名/IP地址
REDIS_PORT             = 6379 # 端口
#REDIS_PASSWORD        =  # 密码
REDIS_DATABASE         = 0 # 数据库

# Redis cache
# ----
REDIS_CACHE_KEY_PREFIX = ca: # 唯一键前缀

46、编辑 \common\config\base.php，在应用程序配置中配置 Redis 连接，且配置缓存组件

        'redisCache' => [
            'class' => 'yii\redis\Cache',
            'keyPrefix' => env('REDIS_CACHE_KEY_PREFIX'), // 唯一键前缀
        ],

        'redis' => [
            'class' => 'yii\redis\Connection',
            'hostname' => env('REDIS_HOSTNAME'),
            'port' => env('REDIS_PORT'),
            'password' => env('REDIS_PASSWORD'),
            'database' => env('REDIS_DATABASE'),
        ],

47、在数据库连接中开启 Schema 缓存，编辑 \common\components\db\ActiveRecord.php

        // 检查数据库连接组件、RBAC组件是否被注册
        if (!(Yii::$app->has($tenantDb) && Yii::$app->has('authManager'))) {
            // 注册数据库连接组件、RBAC组件
            Yii::$app->setComponents([
                $tenantDb => [
                    'class' => 'yii\db\Connection',
                    'dsn' => 'mysql:host=' . $tenantEnv['data']['db_info']['host'] . ';port=3306;dbname=' . $tenantEnv['data']['db_info']['database'] . '',
                    'username' => $tenantEnv['data']['db_info']['login'],
                    'password' => $tenantEnv['data']['db_info']['password'],
                    'tablePrefix' => $tenantEnv['data']['db_info']['prefix'],
                    'charset' => 'utf8',
                    'enableSchemaCache' => YII_ENV_PROD,
                    'schemaCache' => 'redisCache',
                ],
                'authManager' => [
                    'class' => 'yii\rbac\DbManager',
                    'db' => $tenantDb,
                    'itemTable' => '{{%rbac_auth_item}}',
                    'itemChildTable' => '{{%rbac_auth_item_child}}',
                    'assignmentTable' => '{{%rbac_auth_assignment}}',
                    'ruleTable' => '{{%rbac_auth_rule}}'
                ],
            ]);
        }

48、运行后台应用后，查看 Redis 中的数据，数据表的结构已经被缓存了，如图30

49、实现缓存(多租户系统的响应)，编辑 \common\logics\http\tenant\Env.php，运行后台应用后，查看 Redis 中的数据，多租户系统的响应数据已经被缓存了，如图31

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/01/17
 * Time: 15:20
 */

namespace common\logics\http\tenant;

use Yii;
use yii\base\Model;
use yii\web\ServerErrorHttpException;

/**
 * 多租户的模块环境配置
 *
 * @author Qiang Wang <shuijingwanwq@163.com>
 * @since 1.0
 */
class Env extends Model
{
    public $app_name;
    public $secret;
    public $tenant_id;

    public function attributeLabels()
    {
        return [
            'app_name' => \Yii::t('model/http/tenant/env', 'App Name'),
            'secret' => \Yii::t('model/http/tenant/env', 'Secret'),
            'tenant_id' => \Yii::t('model/http/tenant/env', 'Tenant ID'),
        ];
    }

    /**
     * 返回租户模块环境配置信息
     *
     * @return array|false
     *
     * 格式如下：
     *
     * 租户模块环境配置信息
     * [
     *     'message' => '', //说明
     *     'data' => [], //数据
     * ]
     *
     * 失败(将错误保存在 [[yii\base\Model::errors]] 属性中)
     * false
     *
     * @throws ServerErrorHttpException 如果响应状态码不等于20x
     */
    public function getTenantEnv()
    {
        /* 租户ID后续从请求参数中获取 */
        $this->tenant_id = 'default';

        // 设置多租户数据的缓存键
        $redisCache = Yii::$app->redisCache;
        $tenantKey = 'tenant:' . $this->tenant_id;

        // 从缓存中取回多租户数据
        $tenantData = $redisCache[$tenantKey];

        if ($tenantData === false) {
            $this->app_name = env('TENANT_APP_NAME');
            $this->secret = env('TENANT_SECRET');

            $response = Yii::$app->tenantHttp->createRequest()
                ->setMethod('get')
                ->setUrl('getTenantEnv')
                ->setData([
                    'appname' => $this->app_name,
                    'secret' => $this->secret,
                    'tenantid' => $this->tenant_id,
                ])
                ->send();
            // 检查响应状态码是否等于20x
            if ($response->isOk) {
                // 检查业务逻辑是否成功
                if ($response->data['returnCode'] === 0) {
                    $tenantData = ['message' => $response->data['returnDesc'], 'data' => $response->data['returnData']];
                    // 将多租户数据存放到缓存供下次使用
                    $redisCache[$tenantKey] = $tenantData;
                    return $tenantData;
                } else {
                    $this->addError('tenant_id', $response->data['returnDesc']);
                    return false;
                }
            } else {
                throw new ServerErrorHttpException(Yii::t('error', Yii::t('error', Yii::t('error', '20005'), ['statusCode' => $response->getStatusCode()])));
            }
        } else {
            return $tenantData;
        }

    }

}

50、清空Redis，一次请求中，对于多租户系统的HTTP请求仅有1次，如图32

51、默认情况下，缓存中的数据会永久存留，除非它被某些缓存策略强制移除（例如：缓存空间已满，最老的数据会被移除），后续准备实现清除对应缓存数据的接口，以便于多租户系统的数据发生变化时，可以调用清除对应缓存数据的接口