content: /*
   * Copyright 1999-2019 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.cluster.server.envoy.rls.rule;
  
  import java.util.List;
  import java.util.stream.Collectors;
  
  import com.alibaba.csp.sentinel.slots.block.ClusterRuleConstant;
  import com.alibaba.csp.sentinel.slots.block.flow.ClusterFlowConfig;
  import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
  import com.alibaba.csp.sentinel.util.AssertUtil;
  import com.alibaba.csp.sentinel.util.StringUtil;
  
  /**
   * @author Eric Zhao
   * @since 1.7.0
   */
  public final class EnvoySentinelRuleConverter {
  
      /**
       * Currently we use "|" to separate each key/value entries.
       */
      public static final String SEPARATOR = "|";
  
      /**
       * Convert the {@link EnvoyRlsRule} to a list of Sentinel flow rules.
       *
       * @param rule a valid Envoy RLS rule
       * @return converted rules
       */
      public static List<FlowRule> toSentinelFlowRules(EnvoyRlsRule rule) {
          if (!EnvoyRlsRuleManager.isValidRule(rule)) {
              throw new IllegalArgumentException("Not a valid RLS rule");
          }
          return rule.getDescriptors().stream()
              .map(e -> toSentinelFlowRule(rule.getDomain(), e))
              .collect(Collectors.toList());
      }
  
      public static FlowRule toSentinelFlowRule(String domain, EnvoyRlsRule.ResourceDescriptor descriptor) {
          // One descriptor could have only one rule.
          String identifier = generateKey(domain, descriptor);
          long flowId = generateFlowId(identifier);
          return new FlowRule(identifier)
              .setCount(descriptor.getCount())
              .setClusterMode(true)
              .setClusterConfig(new ClusterFlowConfig()
                  .setFlowId(flowId)
                  .setThresholdType(ClusterRuleConstant.FLOW_THRESHOLD_GLOBAL)
                  .setSampleCount(1)
                  .setFallbackToLocalWhenFail(false));
      }
  
      public static long generateFlowId(String key) {
          if (StringUtil.isBlank(key)) {
              return -1L;
          }
          // Add offset to avoid negative ID.
          return (long) Integer.MAX_VALUE + key.hashCode();
      }
  
      public static String generateKey(String domain, EnvoyRlsRule.ResourceDescriptor descriptor) {
          AssertUtil.assertNotBlank(domain, "domain cannot be blank");
          AssertUtil.notNull(descriptor, "EnvoyRlsRule.ResourceDescriptor cannot be null");
          AssertUtil.assertNotEmpty(descriptor.getResources(), "resources in descriptor cannot be null");
  
          StringBuilder sb = new StringBuilder(domain);
          for (EnvoyRlsRule.KeyValueResource resource : descriptor.getResources()) {
              sb.append(SEPARATOR).append(resource.getKey()).append(SEPARATOR).append(resource.getValue());
          }
          return sb.toString();
      }
  
      private EnvoySentinelRuleConverter() {}
  }
  