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.datasource;
  
  import java.util.Arrays;
  import java.util.List;
  import java.util.Optional;
  
  import com.alibaba.csp.sentinel.cluster.server.envoy.rls.SentinelEnvoyRlsConstants;
  import com.alibaba.csp.sentinel.cluster.server.envoy.rls.rule.EnvoyRlsRule;
  import com.alibaba.csp.sentinel.cluster.server.envoy.rls.rule.EnvoyRlsRuleManager;
  import com.alibaba.csp.sentinel.config.SentinelConfig;
  import com.alibaba.csp.sentinel.datasource.FileRefreshableDataSource;
  import com.alibaba.csp.sentinel.datasource.ReadableDataSource;
  import com.alibaba.csp.sentinel.util.StringUtil;
  
  import org.yaml.snakeyaml.Yaml;
  import org.yaml.snakeyaml.representer.Representer;
  
  /**
   * @author Eric Zhao
   * @since 1.7.0
   */
  public class EnvoyRlsRuleDataSourceService {
  
      private final Yaml yaml;
      private ReadableDataSource<String, List<EnvoyRlsRule>> ds;
  
      public EnvoyRlsRuleDataSourceService() {
          this.yaml = createYamlParser();
      }
  
      private Yaml createYamlParser() {
          Representer representer = new Representer();
          representer.getPropertyUtils().setSkipMissingProperties(true);
          return new Yaml(representer);
      }
  
      public synchronized void init() throws Exception {
          if (ds != null) {
              return;
          }
          String configPath = getRuleConfigPath();
          if (StringUtil.isBlank(configPath)) {
              throw new IllegalStateException("Empty rule config path, please set the file path in the env: "
                  + SentinelEnvoyRlsConstants.RULE_FILE_PATH_ENV_KEY);
          }
  
          this.ds = new FileRefreshableDataSource<>(configPath, s -> Arrays.asList(yaml.loadAs(s, EnvoyRlsRule.class)));
          EnvoyRlsRuleManager.register2Property(ds.getProperty());
      }
  
      public synchronized void onShutdown() {
          if (ds != null) {
              try {
                  ds.close();
              } catch (Exception e) {
                  e.printStackTrace();
              }
          }
      }
  
      private String getRuleConfigPath() {
          return Optional.ofNullable(System.getenv(SentinelEnvoyRlsConstants.RULE_FILE_PATH_ENV_KEY))
              .orElse(SentinelConfig.getConfig(SentinelEnvoyRlsConstants.RULE_FILE_PATH_PROPERTY_KEY));
      }
  }
  