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.query.graphql;
  
  import com.linecorp.armeria.common.HttpRequest;
  import com.linecorp.armeria.common.HttpResponse;
  import com.linecorp.armeria.server.ServiceRequestContext;
  import com.linecorp.armeria.server.annotation.Blocking;
  import com.linecorp.armeria.server.annotation.Post;
  import com.linecorp.armeria.server.graphql.GraphqlService;
  import graphql.analysis.MaxQueryComplexityInstrumentation;
  import graphql.schema.GraphQLSchema;
  import lombok.extern.slf4j.Slf4j;
  
  @Slf4j
  public class GraphQLQueryHandler {
      private final GraphqlService graphqlService;
  
      public GraphQLQueryHandler(
          final GraphQLQueryConfig config,
          final GraphQLSchema schema) {
          final int allowedComplexity = config.getMaxQueryComplexity();
          graphqlService =
              GraphqlService
                  .builder()
                  .schema(schema)
                  .instrumentation(new MaxQueryComplexityInstrumentation(allowedComplexity, info -> {
                      log.warn(
                          "Aborting query because it's too complex, maximum allowed is [{}] but was [{}]",
                          allowedComplexity,
                          info.getComplexity());
                      return true;
                  }))
                  .build();
      }
  
      @Blocking
      @Post("/graphql")
      public HttpResponse graphql(
          final ServiceRequestContext ctx,
          final HttpRequest req) throws Exception {
          return graphqlService.serve(ctx, req);
      }
  }
  