org.apache.flink.cdc.debezium.JsonDebeziumDeserializationSchema Maven / Gradle / Ivy

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/*
 * 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.flink.cdc.debezium;

import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.util.Collector;

import org.apache.kafka.connect.json.JsonConverter;
import org.apache.kafka.connect.json.JsonConverterConfig;
import org.apache.kafka.connect.source.SourceRecord;
import org.apache.kafka.connect.storage.ConverterConfig;
import org.apache.kafka.connect.storage.ConverterType;

import java.util.HashMap;
import java.util.Map;

/**
 * A JSON format implementation of {@link DebeziumDeserializationSchema} which deserializes the
 * received {@link SourceRecord} to JSON String.
 */
public class JsonDebeziumDeserializationSchema implements DebeziumDeserializationSchema {

    private static final long serialVersionUID = 1L;

    private transient JsonConverter jsonConverter;

    /**
     * Configuration whether to enable {@link JsonConverterConfig#SCHEMAS_ENABLE_CONFIG} to include
     * schema in messages.
     */
    private final Boolean includeSchema;

    /** The custom configurations for {@link JsonConverter}. */
    private Map customConverterConfigs;

    public JsonDebeziumDeserializationSchema() {
        this(false);
    }

    public JsonDebeziumDeserializationSchema(Boolean includeSchema) {
        this.includeSchema = includeSchema;
    }

    public JsonDebeziumDeserializationSchema(
            Boolean includeSchema, Map customConverterConfigs) {
        this.includeSchema = includeSchema;
        this.customConverterConfigs = customConverterConfigs;
    }

    @Override
    public void deserialize(SourceRecord record, Collector out) throws Exception {
        if (jsonConverter == null) {
            initializeJsonConverter();
        }
        byte[] bytes =
                jsonConverter.fromConnectData(record.topic(), record.valueSchema(), record.value());
        out.collect(new String(bytes));
    }

    /** Initialize {@link JsonConverter} with given configs. */
    private void initializeJsonConverter() {
        jsonConverter = new JsonConverter();
        final HashMap configs = new HashMap<>(2);
        configs.put(ConverterConfig.TYPE_CONFIG, ConverterType.VALUE.getName());
        configs.put(JsonConverterConfig.SCHEMAS_ENABLE_CONFIG, includeSchema);
        if (customConverterConfigs != null) {
            configs.putAll(customConverterConfigs);
        }
        jsonConverter.configure(configs);
    }

    @Override
    public TypeInformation getProducedType() {
        return BasicTypeInfo.STRING_TYPE_INFO;
    }
}