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Posted to issues@flink.apache.org by GitBox <gi...@apache.org> on 2020/05/15 08:46:01 UTC
[GitHub] [flink] wuchong commented on a change in pull request #12152: [FLINK-17149][debezium][canal] Introduce Debezium and Canal changelog format
wuchong commented on a change in pull request #12152:
URL: https://github.com/apache/flink/pull/12152#discussion_r425656042
##########
File path: flink-formats/flink-json/src/main/java/org/apache/flink/formats/json/canal/CanalJsonDeserializationSchema.java
##########
@@ -0,0 +1,179 @@
+/*
+ * 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.formats.json.canal;
+
+import org.apache.flink.api.common.serialization.DeserializationSchema;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.formats.json.JsonRowDataDeserializationSchema;
+import org.apache.flink.table.api.DataTypes;
+import org.apache.flink.table.data.ArrayData;
+import org.apache.flink.table.data.GenericRowData;
+import org.apache.flink.table.data.RowData;
+import org.apache.flink.table.types.DataType;
+import org.apache.flink.table.types.logical.RowType;
+import org.apache.flink.types.RowKind;
+import org.apache.flink.util.Collector;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static java.lang.String.format;
+import static org.apache.flink.table.types.utils.TypeConversions.fromLogicalToDataType;
+
+/**
+ * Deserialization schema from Canal JSON to Flink Table/SQL internal data structure {@link RowData}.
+ * The deserialization schema knows Debezium's schema definition and can extract the database data
+ * and convert into {@link RowData} with {@link RowKind}.
+ *
+ * <p>Deserializes a <code>byte[]</code> message as a JSON object and reads
+ * the specified fields.
+ *
+ * <p>Failures during deserialization are forwarded as wrapped IOExceptions.
+ *
+ * @see <a href="https://github.com/alibaba/canal">Alibaba Canal</a>
+ */
+public class CanalJsonDeserializationSchema implements DeserializationSchema<RowData> {
+ private static final long serialVersionUID = 1L;
+
+ private static final String OP_INSERT = "INSERT";
+ private static final String OP_UPDATE = "UPDATE";
+ private static final String OP_DELETE = "DELETE";
+
+ /** The deserializer to deserialize Debezium JSON data. */
+ private final JsonRowDataDeserializationSchema jsonDeserializer;
+
+ /** TypeInformation of the produced {@link RowData}. **/
+ private final TypeInformation<RowData> resultTypeInfo;
+
+ /** Flag indicating whether to ignore invalid fields/rows (default: throw an exception). */
+ private final boolean ignoreParseErrors;
+
+ /** Number of fields. */
+ private final int fieldCount;
+
+ public CanalJsonDeserializationSchema(
+ RowType rowType,
+ TypeInformation<RowData> resultTypeInfo,
+ boolean ignoreParseErrors) {
+ this.resultTypeInfo = resultTypeInfo;
+ this.ignoreParseErrors = ignoreParseErrors;
+ this.fieldCount = rowType.getFieldCount();
+ this.jsonDeserializer = new JsonRowDataDeserializationSchema(
+ createJsonRowType(fromLogicalToDataType(rowType)),
+ // the result type is never used, so it's fine to pass in Canal's result type
+ resultTypeInfo,
+ false, // ignoreParseErrors already contains the functionality of failOnMissingField
+ ignoreParseErrors);
+
+ }
+
+ @Override
+ public RowData deserialize(byte[] message) throws IOException {
+ throw new RuntimeException(
+ "Please invoke DeserializationSchema#deserialize(byte[], Collector<RowData>) instead.");
+ }
+
+ @Override
+ public void deserialize(byte[] message, Collector<RowData> out) throws IOException {
+ RowData row = jsonDeserializer.deserialize(message);
+ String type = row.getString(2).toString(); // "type" field
+ if (OP_INSERT.equals(type)) {
+ // "data" field is an array of row, contains inserted rows
Review comment:
It's not easy to rewrite in switch case, because we can't allocate local variable with the same naem.
##########
File path: flink-formats/flink-json/src/main/java/org/apache/flink/formats/json/canal/CanalJsonDeserializationSchema.java
##########
@@ -0,0 +1,179 @@
+/*
+ * 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.formats.json.canal;
+
+import org.apache.flink.api.common.serialization.DeserializationSchema;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.formats.json.JsonRowDataDeserializationSchema;
+import org.apache.flink.table.api.DataTypes;
+import org.apache.flink.table.data.ArrayData;
+import org.apache.flink.table.data.GenericRowData;
+import org.apache.flink.table.data.RowData;
+import org.apache.flink.table.types.DataType;
+import org.apache.flink.table.types.logical.RowType;
+import org.apache.flink.types.RowKind;
+import org.apache.flink.util.Collector;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static java.lang.String.format;
+import static org.apache.flink.table.types.utils.TypeConversions.fromLogicalToDataType;
+
+/**
+ * Deserialization schema from Canal JSON to Flink Table/SQL internal data structure {@link RowData}.
+ * The deserialization schema knows Debezium's schema definition and can extract the database data
+ * and convert into {@link RowData} with {@link RowKind}.
+ *
+ * <p>Deserializes a <code>byte[]</code> message as a JSON object and reads
+ * the specified fields.
+ *
+ * <p>Failures during deserialization are forwarded as wrapped IOExceptions.
+ *
+ * @see <a href="https://github.com/alibaba/canal">Alibaba Canal</a>
+ */
+public class CanalJsonDeserializationSchema implements DeserializationSchema<RowData> {
+ private static final long serialVersionUID = 1L;
+
+ private static final String OP_INSERT = "INSERT";
+ private static final String OP_UPDATE = "UPDATE";
+ private static final String OP_DELETE = "DELETE";
+
+ /** The deserializer to deserialize Debezium JSON data. */
+ private final JsonRowDataDeserializationSchema jsonDeserializer;
+
+ /** TypeInformation of the produced {@link RowData}. **/
+ private final TypeInformation<RowData> resultTypeInfo;
+
+ /** Flag indicating whether to ignore invalid fields/rows (default: throw an exception). */
+ private final boolean ignoreParseErrors;
+
+ /** Number of fields. */
+ private final int fieldCount;
+
+ public CanalJsonDeserializationSchema(
+ RowType rowType,
+ TypeInformation<RowData> resultTypeInfo,
+ boolean ignoreParseErrors) {
+ this.resultTypeInfo = resultTypeInfo;
+ this.ignoreParseErrors = ignoreParseErrors;
+ this.fieldCount = rowType.getFieldCount();
+ this.jsonDeserializer = new JsonRowDataDeserializationSchema(
+ createJsonRowType(fromLogicalToDataType(rowType)),
+ // the result type is never used, so it's fine to pass in Canal's result type
+ resultTypeInfo,
+ false, // ignoreParseErrors already contains the functionality of failOnMissingField
+ ignoreParseErrors);
+
+ }
+
+ @Override
+ public RowData deserialize(byte[] message) throws IOException {
+ throw new RuntimeException(
+ "Please invoke DeserializationSchema#deserialize(byte[], Collector<RowData>) instead.");
+ }
+
+ @Override
+ public void deserialize(byte[] message, Collector<RowData> out) throws IOException {
+ RowData row = jsonDeserializer.deserialize(message);
+ String type = row.getString(2).toString(); // "type" field
+ if (OP_INSERT.equals(type)) {
+ // "data" field is an array of row, contains inserted rows
Review comment:
It's not easy to rewrite in switch case, because we can't allocate local variable with the same name.
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