/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.dubbo.rpc.filter;

import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.extension.Activate;
import com.alibaba.dubbo.rpc.Filter;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.Result;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.filter.tps.DefaultTPSLimiter;
import com.alibaba.dubbo.rpc.filter.tps.TPSLimiter;

/**
 * Limit TPS for either service or service's particular method
 * 限制服务或服务的特定方法的TPS,生产者端 tps属性值,这个属性值基于xml和annotation都是不可以配置的,需要注册到注册中心才可以启用
 */
@Activate(group = Constants.PROVIDER, value = Constants.TPS_LIMIT_RATE_KEY)
public class TpsLimitFilter implements Filter {

    private final TPSLimiter tpsLimiter = new DefaultTPSLimiter();

    @Override
    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {

//        已经超过了tps不允许执行业务方法
        if (!tpsLimiter.isAllowable(invoker.getUrl(), invocation)) {
            throw new RpcException(
                    "Failed to invoke service " +
                            invoker.getInterface().getName() +
                            "." +
                            invocation.getMethodName() +
                            " because exceed max service tps.");
        }

//        业务方法执行
        return invoker.invoke(invocation);
    }

}