content: /*
   * Copyright 1999-2021 Alibaba Group Holding Ltd.
   *
   * Licensed 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.csp.sentinel.demo.slotchain;
  
  import com.alibaba.csp.sentinel.Entry;
  import com.alibaba.csp.sentinel.SphU;
  import com.alibaba.csp.sentinel.slots.block.BlockException;
  import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
  import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
  import com.alibaba.csp.sentinel.slots.block.degrade.circuitbreaker.CircuitBreakerStrategy;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.ThreadLocalRandom;
  import java.util.concurrent.TimeUnit;
  
  /**
   * Demo for degrade rule using custom SlotChainBuilder {@link DemoSlotChainBuilder}.
   *
   * You will see this in sentinel-record.log, indicating that the custom slot chain builder is activated:
   * [SlotChainProvider] Global slot chain builder resolved: com.alibaba.csp.sentinel.demo.slotchain.DemoSlotChainBuilder
   *
   * @author cdfive
   */
  public class DemoDegradeRuleApplication {
  
      private static final String RESOURCE_KEY = "abc";
  
      public static void main(String[] args) throws Exception {
          initDegradeRule();
  
          for (int i = 1; i <= 100; i++) {
              Entry entry = null;
              try {
                  entry = SphU.entry(RESOURCE_KEY);
                  TimeUnit.MILLISECONDS.sleep(ThreadLocalRandom.current().nextInt(10, 100));
                  System.out.println(i + "=>" + " passed");
              } catch (BlockException ex) {
                  System.out.println(i + "=>" + " blocked by " + ex.getClass().getSimpleName());
              } finally {
                  if (entry != null) {
                      entry.exit();
                  }
              }
          }
      }
  
      private static void initDegradeRule() {
          List<DegradeRule> rules = new ArrayList<>();
          DegradeRule rule = new DegradeRule(RESOURCE_KEY)
                  .setGrade(CircuitBreakerStrategy.SLOW_REQUEST_RATIO.getType())
                  // Max allowed response time
                  .setCount(20)
                  // Retry timeout (in second)
                  .setTimeWindow(10)
                  // Circuit breaker opens when slow request ratio > 20%
                  .setSlowRatioThreshold(0.2)
                  .setMinRequestAmount(10)
                  .setStatIntervalMs(20000);
          rules.add(rule);
  
          DegradeRuleManager.loadRules(rules);
          System.out.println("Degrade rule loaded: " + rules);
      }
  }
  