flink-doris-connector/src/main/java/org/apache/doris/flink/sink/writer/serializer/jsondebezium/JsonDebeziumDataChange.java

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// 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
//
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package org.apache.doris.flink.sink.writer.serializer.jsondebezium;

import org.apache.flink.annotation.VisibleForTesting;
import org.apache.flink.util.CollectionUtil;
import org.apache.flink.util.StringUtils;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.NullNode;
import org.apache.doris.flink.cfg.DorisOptions;
import org.apache.doris.flink.sink.writer.ChangeEvent;
import org.apache.doris.flink.sink.writer.serializer.DorisRecord;
import org.apache.doris.flink.tools.cdc.SourceSchema;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

import static org.apache.doris.flink.sink.util.DeleteOperation.addDeleteSign;

/**
 * Convert the data change record of the upstream data source into a byte array that can be imported
 * into doris through stream load.<br>
 * Supported data changes include: read, insert, update, delete.
 */
public class JsonDebeziumDataChange implements ChangeEvent {
    private static final Logger LOG = LoggerFactory.getLogger(JsonDebeziumDataChange.class);

    private static final String OP_READ = "r"; // snapshot read
    private static final String OP_CREATE = "c"; // insert
    private static final String OP_UPDATE = "u"; // update
    private static final String OP_DELETE = "d"; // delete
    private final ObjectMapper objectMapper;
    private final DorisOptions dorisOptions;
    private final boolean ignoreUpdateBefore;
    private final String lineDelimiter;
    private JsonDebeziumChangeContext changeContext;

    public JsonDebeziumDataChange(JsonDebeziumChangeContext changeContext) {
        this.changeContext = changeContext;
        this.dorisOptions = changeContext.getDorisOptions();
        this.objectMapper = changeContext.getObjectMapper();
        this.ignoreUpdateBefore = changeContext.isIgnoreUpdateBefore();
        this.lineDelimiter = changeContext.getLineDelimiter();
    }

    public DorisRecord serialize(String record, JsonNode recordRoot, String op) throws IOException {
        // Filter out table records that are not in tableMapping
        String cdcTableIdentifier = getCdcTableIdentifier(recordRoot);
        String dorisTableIdentifier = getDorisTableIdentifier(cdcTableIdentifier);
        if (StringUtils.isNullOrWhitespaceOnly(dorisTableIdentifier)) {
            LOG.warn(
                    "filter table {}, because it is not listened, record detail is {}",
                    cdcTableIdentifier,
                    record);
            return null;
        }

        Map<String, Object> valueMap;
        switch (op) {
            case OP_READ:
            case OP_CREATE:
                valueMap = extractAfterRow(recordRoot);
                addDeleteSign(valueMap, false);
                break;
            case OP_UPDATE:
                return DorisRecord.of(dorisTableIdentifier, extractUpdate(recordRoot));
            case OP_DELETE:
                valueMap = extractBeforeRow(recordRoot);
                addDeleteSign(valueMap, true);
                break;
            default:
                LOG.error("parse record fail, unknown op {} in {}", op, record);
                return null;
        }

        return DorisRecord.of(
                dorisTableIdentifier,
                objectMapper.writeValueAsString(valueMap).getBytes(StandardCharsets.UTF_8));
    }

    /**
     * Change the update event into two.
     *
     * @param recordRoot
     * @return
     */
    private byte[] extractUpdate(JsonNode recordRoot) throws JsonProcessingException {
        StringBuilder updateRow = new StringBuilder();
        if (!ignoreUpdateBefore) {
            // convert delete
            Map<String, Object> beforeRow = extractBeforeRow(recordRoot);
            addDeleteSign(beforeRow, true);
            updateRow.append(objectMapper.writeValueAsString(beforeRow)).append(this.lineDelimiter);
        }

        // convert insert
        Map<String, Object> afterRow = extractAfterRow(recordRoot);
        addDeleteSign(afterRow, false);
        updateRow.append(objectMapper.writeValueAsString(afterRow));
        return updateRow.toString().getBytes(StandardCharsets.UTF_8);
    }

    @VisibleForTesting
    public String getCdcTableIdentifier(JsonNode record) {
        String db = extractJsonNode(record.get("source"), "db");
        String schema = extractJsonNode(record.get("source"), "schema");
        String table = extractJsonNode(record.get("source"), "table");
        return SourceSchema.getString(db, schema, table);
    }

    @VisibleForTesting
    public String getDorisTableIdentifier(String cdcTableIdentifier) {
        if (!StringUtils.isNullOrWhitespaceOnly(dorisOptions.getTableIdentifier())) {
            return dorisOptions.getTableIdentifier();
        }
        Map<String, String> tableMapping = changeContext.getTableMapping();
        if (!CollectionUtil.isNullOrEmpty(tableMapping)
                && !StringUtils.isNullOrWhitespaceOnly(cdcTableIdentifier)
                && tableMapping.get(cdcTableIdentifier) != null) {
            return tableMapping.get(cdcTableIdentifier);
        }
        return null;
    }

    private String extractJsonNode(JsonNode record, String key) {
        return record != null && record.get(key) != null && !(record.get(key) instanceof NullNode)
                ? record.get(key).asText()
                : null;
    }

    private Map<String, Object> extractBeforeRow(JsonNode record) {
        return extractRow(record.get("before"));
    }

    private Map<String, Object> extractAfterRow(JsonNode record) {
        return extractRow(record.get("after"));
    }

    private Map<String, Object> extractRow(JsonNode recordRow) {
        Map<String, Object> recordMap =
                objectMapper.convertValue(recordRow, new TypeReference<Map<String, Object>>() {});
        return recordMap != null ? recordMap : new HashMap<>();
    }
}