content: /*
   * 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 com.datastax.oss.driver.internal.core.tracker;
  
  import com.datastax.oss.driver.api.core.context.DriverContext;
  import com.datastax.oss.driver.api.core.session.Request;
  import com.datastax.oss.driver.api.core.tracker.RequestIdGenerator;
  import com.datastax.oss.driver.shaded.guava.common.io.BaseEncoding;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import java.security.SecureRandom;
  import java.util.Random;
  
  public class W3CContextRequestIdGenerator implements RequestIdGenerator {
  
    private final Random random = new SecureRandom();
    private final BaseEncoding baseEncoding = BaseEncoding.base16().lowerCase();
    private final String payloadKey;
  
    public W3CContextRequestIdGenerator(DriverContext context) {
      payloadKey = RequestIdGenerator.super.getCustomPayloadKey();
    }
  
    public W3CContextRequestIdGenerator(String payloadKey) {
      this.payloadKey = payloadKey;
    }
  
    /** Random 16 bytes, e.g. "4bf92f3577b34da6a3ce929d0e0e4736" */
    @Override
    public String getSessionRequestId() {
      byte[] bytes = new byte[16];
      random.nextBytes(bytes);
      return baseEncoding.encode(bytes);
    }
  
    /**
     * Following the format of W3C "traceparent" spec,
     * https://www.w3.org/TR/trace-context/#traceparent-header-field-values e.g.
     * "00-4bf92f3577b34da6a3ce929d0e0e4736-a3ce929d0e0e4736-01" All node requests in the same session
     * request share the same "trace-id" field value
     */
    @Override
    public String getNodeRequestId(@NonNull Request statement, @NonNull String parentId) {
      byte[] bytes = new byte[8];
      random.nextBytes(bytes);
      return String.format("00-%s-%s-00", parentId, baseEncoding.encode(bytes));
    }
  
    @Override
    public String getCustomPayloadKey() {
      return this.payloadKey;
    }
  }
  