Fix handling of JSON columns (#3643)

[ti-chi-bot]

This is an automated cherry-pick of #3643

What problem does this PR solve?

Closes #3624

What is changed and how it works?

When inserting valid JSON into a column of the json type this happens:

panic: interface conversion: interface {} is string, not json.BinaryJSON

goroutine 1228 [running]:
github.com/pingcap/ticdc/cdc/sink/codec.columnToAvroNativeData(0xc003f93bc0, 0xc000e14cb0, 0xc0027471c8, 0x2, 0xc00197a1a8, 0xd, 0x0, 0x0)
	github.com/pingcap/ticdc/cdc/sink/codec/avro.go:479 +0x19c5
github.com/pingcap/ticdc/cdc/sink/codec.rowToAvroNativeData(0xc00274e1f0, 0x2, 0x2, 0xc000e14cb0, 0x4, 0xc002747190, 0xc, 0x37)
	github.com/pingcap/ticdc/cdc/sink/codec/avro.go:274 +0xa8
github.com/pingcap/ticdc/cdc/sink/codec.avroEncode(0xc003f93bf0, 0xc0026817c0, 0x5f5736086ec0002, 0xc00274e1f0, 0x2, 0x2, 0xc000e14cb0, 0xc0044ef560, 0xc0044ef570, 0x3a071e8)
	github.com/pingcap/ticdc/cdc/sink/codec/avro.go:197 +0x191
github.com/pingcap/ticdc/cdc/sink/codec.(*AvroEventBatchEncoder).AppendRowChangedEvent(0xc002615200, 0xc001b52280, 0x0, 0x0, 0x3)
	github.com/pingcap/ticdc/cdc/sink/codec/avro.go:94 +0x830
github.com/pingcap/ticdc/cdc/sink.(*mqSink).runWorker(0xc0018fc280, 0x3a34708, 0xc0018aa1c0, 0x2, 0x0, 0x0)
	github.com/pingcap/ticdc/cdc/sink/mq.go:345 +0x3f1
github.com/pingcap/ticdc/cdc/sink.(*mqSink).run.func1(0x0, 0x0)
	github.com/pingcap/ticdc/cdc/sink/mq.go:275 +0x46
golang.org/x/sync/errgroup.(*Group).Go.func1(0xc0026151d0, 0xc002941400)
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x59
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x66

The Value seems to be a string instead of json.BinaryJSON as the error indicates

(dlv) print col
*github.com/pingcap/ticdc/cdc/model.Column {
	Name: "json_payload",
	Type: 245,
	Flag: BinaryFlag|NullableFlag (65),
	Value: interface {}(string) "{\"foo\": \"bar\"}",}

Manual test

Setup a test environment:

tiup playground v5.2.2 --tiflash 0 --without-monitor=false
./bin/cdc server
curl --silent --output docker-compose.yml https://raw.githubusercontent.com/confluentinc/cp-all-in-one/6.2.0-post/cp-all-in-one-community/docker-compose.yml
sudo docker-compose up -d
./bin/cdc cli changefeed create --no-confirm --changefeed-id="simple-replication-task" --sort-engine="unified" --sink-uri="kafka://127.0.0.1:9092/cdc-test?protocol=avro&kafka-version=2.8.0" --log-level debug --opts registry="http://127.0.0.1:8081"

Create a table and insert some JSON:

CREATE TABLE `sample_table` (
  `id` bigint(20) unsigned primary key NOT NULL AUTO_INCREMENT,
  `json_payload` json DEFAULT NULL
);
INSERT INTO sample_table(json_payload) VALUES(NULL);
INSERT INTO sample_table(json_payload) VALUES(JSON_OBJECT('foo', 'bar'));
SELECT * FROM sample_table;

Start an Avro Console Consumer:

sudo docker-compose exec schema-registry /bin/sh
kafka-avro-console-consumer  --topic cdc-test --from-beginning --bootstrap-server broker:29092

Output:

{"id":"\t","json_payload":{"string":"{\"foo\": \"bar\"}"}}

Check List

Tests

• Manual test (add detailed scripts or steps below)

Related changes

• Need to cherry-pick to the release branch

Release note

The Avro sink was updated to handle JSON columns

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[amyangfei]

/merge

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This pull request has been accepted and is ready to merge.

Commit hash: e189e50

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