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 org.apache.kafka.connect.transforms;
  
  import org.apache.kafka.common.cache.Cache;
  import org.apache.kafka.common.cache.LRUCache;
  import org.apache.kafka.common.cache.SynchronizedCache;
  import org.apache.kafka.common.config.ConfigDef;
  import org.apache.kafka.common.config.ConfigException;
  import org.apache.kafka.common.utils.AppInfoParser;
  import org.apache.kafka.connect.components.Versioned;
  import org.apache.kafka.connect.connector.ConnectRecord;
  import org.apache.kafka.connect.data.Field;
  import org.apache.kafka.connect.data.Schema;
  import org.apache.kafka.connect.data.SchemaBuilder;
  import org.apache.kafka.connect.data.Struct;
  import org.apache.kafka.connect.data.Timestamp;
  import org.apache.kafka.connect.transforms.util.SchemaUtil;
  import org.apache.kafka.connect.transforms.util.SimpleConfig;
  
  import java.util.Date;
  import java.util.HashMap;
  import java.util.Map;
  
  import static org.apache.kafka.connect.transforms.util.Requirements.requireMap;
  import static org.apache.kafka.connect.transforms.util.Requirements.requireSinkRecord;
  import static org.apache.kafka.connect.transforms.util.Requirements.requireStruct;
  
  public abstract class InsertField<R extends ConnectRecord<R>> implements Transformation<R>, Versioned {
  
      public static final String OVERVIEW_DOC =
              "Insert field(s) using attributes from the record metadata or a configured static value."
                      + "<p/>Use the concrete transformation type designed for the record key (<code>" + Key.class.getName() + "</code>) "
                      + "or value (<code>" + Value.class.getName() + "</code>).";
  
      private interface ConfigName {
          String TOPIC_FIELD = "topic.field";
          String PARTITION_FIELD = "partition.field";
          String OFFSET_FIELD = "offset.field";
          String TIMESTAMP_FIELD = "timestamp.field";
          String STATIC_FIELD = "static.field";
          String STATIC_VALUE = "static.value";
          String REPLACE_NULL_WITH_DEFAULT = "replace.null.with.default";
      }
  
      private static final String OPTIONALITY_DOC = "Suffix with <code>!</code> to make this a required field, or <code>?</code> to keep it optional (the default).";
  
      public static final ConfigDef CONFIG_DEF = new ConfigDef()
              .define(ConfigName.TOPIC_FIELD, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                      "Field name for Kafka topic. " + OPTIONALITY_DOC)
              .define(ConfigName.PARTITION_FIELD, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                      "Field name for Kafka partition. " + OPTIONALITY_DOC)
              .define(ConfigName.OFFSET_FIELD, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                      "Field name for Kafka offset - only applicable to sink connectors.<br/>" + OPTIONALITY_DOC)
              .define(ConfigName.TIMESTAMP_FIELD, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                      "Field name for record timestamp. " + OPTIONALITY_DOC)
              .define(ConfigName.STATIC_FIELD, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                      "Field name for static data field. " + OPTIONALITY_DOC)
              .define(ConfigName.STATIC_VALUE, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                      "Static field value, if field name configured.")
              .define(ConfigName.REPLACE_NULL_WITH_DEFAULT, ConfigDef.Type.BOOLEAN, true, ConfigDef.Importance.MEDIUM,
                      "Whether to replace fields that have a default value and that are null to the default value. When set to true, the default value is used, otherwise null is used.");
  
      private static final String PURPOSE = "field insertion";
  
      private static final Schema OPTIONAL_TIMESTAMP_SCHEMA = Timestamp.builder().optional().build();
  
      private static final class InsertionSpec {
          final String name;
          final boolean optional;
  
          private InsertionSpec(String name, boolean optional) {
              this.name = name;
              this.optional = optional;
          }
  
          public static InsertionSpec parse(String spec) {
              if (spec == null) return null;
              if (spec.endsWith("?")) {
                  return new InsertionSpec(spec.substring(0, spec.length() - 1), true);
              }
              if (spec.endsWith("!")) {
                  return new InsertionSpec(spec.substring(0, spec.length() - 1), false);
              }
              return new InsertionSpec(spec, true);
          }
      }
  
      private InsertionSpec topicField;
      private InsertionSpec partitionField;
      private InsertionSpec offsetField;
      private InsertionSpec timestampField;
      private InsertionSpec staticField;
      private String staticValue;
      private boolean replaceNullWithDefault;
  
      private Cache<Schema, Schema> schemaUpdateCache;
  
      @Override
      public String version() {
          return AppInfoParser.getVersion();
      }
  
      @Override
      public void configure(Map<String, ?> props) {
          final SimpleConfig config = new SimpleConfig(CONFIG_DEF, props);
          topicField = InsertionSpec.parse(config.getString(ConfigName.TOPIC_FIELD));
          partitionField = InsertionSpec.parse(config.getString(ConfigName.PARTITION_FIELD));
          offsetField = InsertionSpec.parse(config.getString(ConfigName.OFFSET_FIELD));
          timestampField = InsertionSpec.parse(config.getString(ConfigName.TIMESTAMP_FIELD));
          staticField = InsertionSpec.parse(config.getString(ConfigName.STATIC_FIELD));
          staticValue = config.getString(ConfigName.STATIC_VALUE);
          replaceNullWithDefault = config.getBoolean(ConfigName.REPLACE_NULL_WITH_DEFAULT);
  
          if (topicField == null && partitionField == null && offsetField == null && timestampField == null && staticField == null) {
              throw new ConfigException("No field insertion configured");
          }
  
          if (staticField != null && staticValue == null) {
              throw new ConfigException(ConfigName.STATIC_VALUE, null, "No value specified for static field: " + staticField);
          }
  
          schemaUpdateCache = new SynchronizedCache<>(new LRUCache<>(16));
      }
  
      @Override
      public R apply(R record) {
          if (operatingValue(record) == null) {
              return record;
          } else if (operatingSchema(record) == null) {
              return applySchemaless(record);
          } else {
              return applyWithSchema(record);
          }
      }
  
      private R applySchemaless(R record) {
          final Map<String, Object> value = requireMap(operatingValue(record), PURPOSE);
  
          final Map<String, Object> updatedValue = new HashMap<>(value);
  
          if (topicField != null) {
              updatedValue.put(topicField.name, record.topic());
          }
          if (partitionField != null && record.kafkaPartition() != null) {
              updatedValue.put(partitionField.name, record.kafkaPartition());
          }
          if (offsetField != null) {
              updatedValue.put(offsetField.name, requireSinkRecord(record, PURPOSE).kafkaOffset());
          }
          if (timestampField != null && record.timestamp() != null) {
              updatedValue.put(timestampField.name, record.timestamp());
          }
          if (staticField != null && staticValue != null) {
              updatedValue.put(staticField.name, staticValue);
          }
  
          return newRecord(record, null, updatedValue);
      }
  
      private R applyWithSchema(R record) {
          final Struct value = requireStruct(operatingValue(record), PURPOSE);
  
          Schema updatedSchema = schemaUpdateCache.get(value.schema());
          if (updatedSchema == null) {
              updatedSchema = makeUpdatedSchema(value.schema());
              schemaUpdateCache.put(value.schema(), updatedSchema);
          }
  
          final Struct updatedValue = new Struct(updatedSchema);
  
          for (Field field : value.schema().fields()) {
              updatedValue.put(field.name(), getFieldValue(value, field));
          }
  
          if (topicField != null) {
              updatedValue.put(topicField.name, record.topic());
          }
          if (partitionField != null && record.kafkaPartition() != null) {
              updatedValue.put(partitionField.name, record.kafkaPartition());
          }
          if (offsetField != null) {
              updatedValue.put(offsetField.name, requireSinkRecord(record, PURPOSE).kafkaOffset());
          }
          if (timestampField != null && record.timestamp() != null) {
              updatedValue.put(timestampField.name, new Date(record.timestamp()));
          }
          if (staticField != null && staticValue != null) {
              updatedValue.put(staticField.name, staticValue);
          }
  
          return newRecord(record, updatedSchema, updatedValue);
      }
  
      private Schema makeUpdatedSchema(Schema schema) {
          final SchemaBuilder builder = SchemaUtil.copySchemaBasics(schema, SchemaBuilder.struct());
  
          for (Field field : schema.fields()) {
              builder.field(field.name(), field.schema());
          }
  
          if (topicField != null) {
              builder.field(topicField.name, topicField.optional ? Schema.OPTIONAL_STRING_SCHEMA : Schema.STRING_SCHEMA);
          }
          if (partitionField != null) {
              builder.field(partitionField.name, partitionField.optional ? Schema.OPTIONAL_INT32_SCHEMA : Schema.INT32_SCHEMA);
          }
          if (offsetField != null) {
              builder.field(offsetField.name, offsetField.optional ? Schema.OPTIONAL_INT64_SCHEMA : Schema.INT64_SCHEMA);
          }
          if (timestampField != null) {
              builder.field(timestampField.name, timestampField.optional ? OPTIONAL_TIMESTAMP_SCHEMA : Timestamp.SCHEMA);
          }
          if (staticField != null) {
              builder.field(staticField.name, staticField.optional ? Schema.OPTIONAL_STRING_SCHEMA : Schema.STRING_SCHEMA);
          }
  
          return builder.build();
      }
  
      private Object getFieldValue(Struct value, Field field) {
          if (replaceNullWithDefault) {
              return value.get(field);
          }
          return value.getWithoutDefault(field.name());
      }
  
      @Override
      public void close() {
          schemaUpdateCache = null;
      }
  
      @Override
      public ConfigDef config() {
          return CONFIG_DEF;
      }
  
      protected abstract Schema operatingSchema(R record);
  
      protected abstract Object operatingValue(R record);
  
      protected abstract R newRecord(R record, Schema updatedSchema, Object updatedValue);
  
      public static class Key<R extends ConnectRecord<R>> extends InsertField<R> {
  
          @Override
          protected Schema operatingSchema(R record) {
              return record.keySchema();
          }
  
          @Override
          protected Object operatingValue(R record) {
              return record.key();
          }
  
          @Override
          protected R newRecord(R record, Schema updatedSchema, Object updatedValue) {
              return record.newRecord(record.topic(), record.kafkaPartition(), updatedSchema, updatedValue, record.valueSchema(), record.value(), record.timestamp());
          }
  
      }
  
      public static class Value<R extends ConnectRecord<R>> extends InsertField<R> {
  
          @Override
          protected Schema operatingSchema(R record) {
              return record.valueSchema();
          }
  
          @Override
          protected Object operatingValue(R record) {
              return record.value();
          }
  
          @Override
          protected R newRecord(R record, Schema updatedSchema, Object updatedValue) {
              return record.newRecord(record.topic(), record.kafkaPartition(), record.keySchema(), record.key(), updatedSchema, updatedValue, record.timestamp());
          }
  
      }
  
  }
  