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.analyzer.provider.trace;
  
  import com.google.common.base.Strings;
  import java.io.FileNotFoundException;
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  import java.util.stream.StreamSupport;
  import lombok.Getter;
  import lombok.Setter;
  import lombok.ToString;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.analyzer.module.AnalyzerModule;
  import org.apache.skywalking.oap.server.configuration.api.ConfigChangeWatcher;
  import org.apache.skywalking.oap.server.library.module.ModuleProvider;
  import org.apache.skywalking.oap.server.library.util.ResourceUtils;
  import org.apache.skywalking.oap.server.library.util.yaml.ClassFilterConstructor;
  import org.yaml.snakeyaml.Yaml;
  
  import static java.util.Objects.isNull;
  
  @Slf4j
  public class UninstrumentedGatewaysConfig extends ConfigChangeWatcher {
      private final AtomicReference<String> settingsString;
  
      private volatile Map<String, GatewayInstanceInfo> gatewayInstanceKeyedByAddress = Collections.emptyMap();
  
      public UninstrumentedGatewaysConfig(ModuleProvider provider) {
          super(AnalyzerModule.NAME, provider, "uninstrumentedGateways");
          this.settingsString = new AtomicReference<>(null);
          final GatewayInfos defaultGateways = parseGatewaysFromFile("gateways.yml");
          log.info("Default configured gateways: {}", defaultGateways);
          onGatewaysUpdated(defaultGateways);
      }
  
      private void activeSetting(String config) {
          if (log.isDebugEnabled()) {
              log.debug("Updating using new static config: {}", config);
          }
          this.settingsString.set(config);
          onGatewaysUpdated(parseGatewaysFromYml(Strings.nullToEmpty(config)));
      }
  
      @Override
      public void notify(ConfigChangeEvent value) {
          if (EventType.DELETE.equals(value.getEventType())) {
              activeSetting(null);
          } else {
              activeSetting(value.getNewValue());
          }
      }
  
      @Override
      public String value() {
          return settingsString.get();
      }
  
      private void onGatewaysUpdated(final GatewayInfos gateways) {
          log.info("Updating uninstrumented gateways with: {}", gateways);
          if (isNull(gateways)) {
              gatewayInstanceKeyedByAddress = Collections.emptyMap();
          } else {
              gatewayInstanceKeyedByAddress = StreamSupport.stream(gateways.spliterator(), false)
                                                           .flatMap(instance -> instance.getInstances().stream())
                                                           .collect(
                                                               Collectors.toMap(GatewayInstanceInfo::getAddress, Function
                                                                   .identity()));
          }
      }
  
      public boolean isAddressConfiguredAsGateway(final String address) {
          final boolean isConfiguredAsGateway = gatewayInstanceKeyedByAddress.get(address) != null;
          if (log.isDebugEnabled()) {
              log.debug("Address [{}] is configured as gateway: {}", address, isConfiguredAsGateway);
          }
          return isConfiguredAsGateway;
      }
  
      private GatewayInfos parseGatewaysFromFile(final String file) {
          try {
              final Reader reader = ResourceUtils.read(file);
              return new Yaml(new ClassFilterConstructor(new Class[] {
                  GatewayInfos.class,
                  GatewayInfo.class,
                  GatewayInstanceInfo.class,
                  }))
                  .loadAs(reader, GatewayInfos.class);
          } catch (FileNotFoundException e) {
              log.error("Cannot load gateways from: {}", file, e);
          }
          return GatewayInfos.EMPTY;
      }
  
      private GatewayInfos parseGatewaysFromYml(final String ymlContent) {
          try {
              return new Yaml(new ClassFilterConstructor(new Class[] {
                  GatewayInfos.class,
                  GatewayInfo.class,
                  GatewayInstanceInfo.class,
                  }))
                  .loadAs(ymlContent, GatewayInfos.class);
          } catch (Exception e) {
              log.error("Failed to parse yml content as gateways: \n{}", ymlContent, e);
          }
          return GatewayInfos.EMPTY;
      }
  
      @Getter
      @Setter
      @ToString
      public static class GatewayInfo {
          private String name;
  
          private List<GatewayInstanceInfo> instances;
      }
  
      @ToString
      public static class GatewayInfos implements Iterable<GatewayInfo> {
          static final GatewayInfos EMPTY = new GatewayInfos();
  
          @Getter
          @Setter
          private Collection<GatewayInfo> gateways;
  
          GatewayInfos() {
              gateways = new ArrayList<>();
          }
  
          @Override
          public Iterator<GatewayInfo> iterator() {
              return gateways.iterator();
          }
      }
  
      @Getter
      @Setter
      @ToString
      public static class GatewayInstanceInfo {
          private String host;
  
          private Integer port;
  
          String getAddress() {
              return getHost() + ":" + (isNull(getPort()) || getPort() <= 0 ? "80" : getPort());
          }
      }
  }
  