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.library.elasticsearch.client;
  
  import com.linecorp.armeria.client.WebClient;
  import com.linecorp.armeria.common.HttpData;
  import com.linecorp.armeria.common.HttpStatus;
  import com.linecorp.armeria.common.util.Exceptions;
  import java.io.InputStream;
  import java.util.Map;
  import java.util.Optional;
  import java.util.concurrent.CompletableFuture;
  import lombok.RequiredArgsConstructor;
  import lombok.SneakyThrows;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.library.elasticsearch.ElasticSearchVersion;
  import org.apache.skywalking.library.elasticsearch.response.IndexTemplate;
  import org.apache.skywalking.library.elasticsearch.response.IndexTemplates;
  import org.apache.skywalking.library.elasticsearch.response.Mappings;
  
  @Slf4j
  @RequiredArgsConstructor
  public final class TemplateClient {
      private final CompletableFuture<ElasticSearchVersion> version;
  
      private final WebClient client;
  
      @SneakyThrows
      public boolean exists(String name) {
          final CompletableFuture<Boolean> future = version.thenCompose(
              v -> client.execute(v.requestFactory().template().exists(name))
                         .aggregate().thenApply(response -> {
                      final HttpStatus status = response.status();
                      if (status == HttpStatus.OK) {
                          return true;
                      } else if (status == HttpStatus.NOT_FOUND) {
                          return false;
                      }
                      throw new RuntimeException(response.contentUtf8());
                  }));
          future.whenComplete((result, exception) -> {
              if (exception != null) {
                  log.error("Failed to check whether template {} exists", name, exception);
                  return;
              }
              if (log.isDebugEnabled()) {
                  log.debug("Succeeded to check whether template {} exists {}", name, result);
              }
          });
          return future.get();
      }
  
      @SneakyThrows
      public Optional<IndexTemplate> get(String name) {
          final CompletableFuture<Optional<IndexTemplate>> future =
              version.thenCompose(
                  v -> client.execute(v.requestFactory().template().get(name))
                             .aggregate().thenApply(response -> {
                          final HttpStatus status = response.status();
                          if (status == HttpStatus.NOT_FOUND) {
                              return Optional.empty();
                          }
                          if (status != HttpStatus.OK) {
                              throw new RuntimeException(response.contentUtf8());
                          }
  
                          try (final HttpData content = response.content();
                               final InputStream is = content.toInputStream()) {
                              final IndexTemplates templates =
                                  v.codec().decode(is, IndexTemplates.class);
                              return templates.get(name);
                          } catch (Exception e) {
                              return Exceptions.throwUnsafely(e);
                          }
                      }));
          future.whenComplete((result, exception) -> {
              if (exception != null) {
                  log.error("Failed to get index template {}", name, exception);
                  return;
              }
              if (log.isDebugEnabled()) {
                  log.debug("Succeeded to get index template {}, {}", name, result);
              }
          });
          return future.get();
      }
  
      @SneakyThrows
      public boolean delete(String name) {
          final CompletableFuture<Boolean> future = version.thenCompose(
              v -> client.execute(v.requestFactory().template().delete(name))
                         .aggregate().thenApply(response -> {
                      if (response.status() == HttpStatus.OK) {
                          return true;
                      }
                      throw new RuntimeException(response.contentUtf8());
                  }));
          future.whenComplete((result, exception) -> {
              if (exception != null) {
                  log.error("Failed to delete index template {}", name, exception);
                  return;
              }
              if (log.isDebugEnabled()) {
                  log.debug("Succeeded to delete index template {}, {}", name, result);
              }
          });
          return future.get();
      }
  
      @SneakyThrows
      public boolean createOrUpdate(String name, Map<String, Object> settings,
                                    Mappings mappings, int order) {
          final CompletableFuture<Boolean> future = version.thenCompose(
              v -> client.execute(v.requestFactory().template()
                                   .createOrUpdate(name, settings, mappings, order))
                         .aggregate().thenApply(response -> {
                      if (response.status() == HttpStatus.OK) {
                          return true;
                      }
                      throw new RuntimeException(response.contentUtf8());
                  }));
          future.whenComplete((result, exception) -> {
              if (exception != null) {
                  log.error("Failed to create / update index template {}", name, exception);
                  return;
              }
              if (log.isDebugEnabled()) {
                  log.debug("Succeeded to create / update index template {}, {}", name, result);
              }
          });
          return future.get();
      }
  
  }
  