MongoDB Kafka Sink 连接器不处理 RenameByRegex 处理器

Question

I need to listening events from a Kafka Topic and Sink to a collection in MongoDB. The message contains an nested object with an id property, like in the example above.

{
    "testId": 1,
    "foo": "bar",
    "foos": [{ "id":"aaaaqqqq-rrrrr" }]
}

I'm trying to rename this nested id to _id with RegExp

{
        "connector.class":"com.mongodb.kafka.connect.MongoSinkConnector",
        "topics": "test",
        "connection.uri": "mongodb://mongo:27017",
        "database": "test_db",
        "collection": "test",
        "key.converter": "org.apache.kafka.connect.storage.StringConverter",
        "value.converter": "org.apache.kafka.connect.json.JsonConverter",
        "value.converter.schemas.enable": "false",
        "document.id.strategy": "com.mongodb.kafka.connect.sink.processor.id.strategy.PartialValueStrategy",
        "value.projection.list":"testId",
        "value.projection.type": "whitelist",
        "post.processor.chain": "com.mongodb.kafka.connect.sink.processor.DocumentIdAdder, com.mongodb.kafka.connect.sink.processor.field.renaming.RenameByRegex",
        "field.renamer.regexp": "[{\"regexp\":\"\b(id)\b\", \"pattern\":\"\b(id)\b\",\"replace\":\"_id\"}]"
    }

And the result of a config/validate is 500 Internal Server Error , with that message:

{
    "error_code": 500,
    "message": null
}

I missing something or is a issue?

Answer 1

I think all you want is Kafka Connect Single Message Transform (SMT) and more precisely ReplaceField :

Filter or rename fields within a Struct or Map.

---

The following will replace id field name with _id :

"transforms": "RenameField",
"transforms.RenameField.type": "org.apache.kafka.connect.transforms.ReplaceField$Value",
"transforms.RenameField.renames": "id:_id"

---

In your case, before applying the above trasnformation you might also want to Flatten foos :

"transforms": "flatten",
"transforms.flatten.type": "org.apache.kafka.connect.transforms.Flatten$Value",
"transforms.flatten.delimiter": "."

and finally apply the transformation for renaming the field:

"transforms": "RenameField",
"transforms.RenameField.type": "org.apache.kafka.connect.transforms.ReplaceField$Value",
"transforms.RenameField.renames": "foos.id:foos._id"