code: /*
   * 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 org.apache.skywalking.oap.server.receiver.configuration.discovery;
  
  import com.google.common.hash.Hashing;
  import java.io.InputStream;
  import java.io.Reader;
  import java.nio.charset.StandardCharsets;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import lombok.extern.slf4j.Slf4j;
  import org.yaml.snakeyaml.LoaderOptions;
  import org.yaml.snakeyaml.Yaml;
  import org.yaml.snakeyaml.constructor.SafeConstructor;
  
  /**
   * Used to parse the String configuration to AgentConfigurations.
   */
  @Slf4j
  public class AgentConfigurationsReader {
      private Map yamlData;
  
      public AgentConfigurationsReader(InputStream inputStream) {
          Yaml yaml = new Yaml(new SafeConstructor(new LoaderOptions()));
          yamlData = yaml.load(inputStream);
      }
  
      public AgentConfigurationsReader(Reader io) {
          Yaml yaml = new Yaml(new SafeConstructor(new LoaderOptions()));
          yamlData = yaml.load(io);
      }
  
      public AgentConfigurationsTable readAgentConfigurationsTable() {
          AgentConfigurationsTable agentConfigurationsTable = new AgentConfigurationsTable();
          try {
              if (Objects.nonNull(yamlData)) {
                  Map configurationsData = (Map) yamlData.get("configurations");
                  if (configurationsData != null) {
                      configurationsData.forEach((k, v) -> {
                          Map map = (Map) v;
                          StringBuilder serviceConfigStr = new StringBuilder();
                          Map<String, String> config = new HashMap<>(map.size());
                          map.forEach((key, value) -> {
                              config.put(key.toString(), value.toString());
  
                              serviceConfigStr.append(key).append(":").append(value);
                          });
  
                          // noinspection UnstableApiUsage
                          AgentConfigurations agentConfigurations = new AgentConfigurations(
                              k.toString(), config,
                              Hashing.sha512().hashString(
                                  serviceConfigStr.toString(), StandardCharsets.UTF_8).toString()
                          );
                          agentConfigurationsTable.getAgentConfigurationsCache()
                                                  .put(agentConfigurations.getService(), agentConfigurations);
                      });
                  }
              }
          } catch (Exception e) {
              log.error("Read ConfigurationDiscovery configurations error.", e);
          }
          return agentConfigurationsTable;
      }
  }
  