Failed to register Protobuf Kryo serialization

[Svend Vanderveken]

Hi all,

I'm failing to setup an example of wire serialization with Protobuf, could
you help me figure out what I'm doing wrong?

I'm using a simple protobuf schema:

```

syntax = "proto3";

import "google/protobuf/wrappers.proto";
option java_multiple_files = true;

message DemoUserEvent {
  Metadata metadata = 1;
  oneof payload {
    Created created = 10;
    Updated updated = 11;
  }

  message Created {...}

  message Updated {...}

  ...

}

```


>From which I'm generating java from this Gradle plugin:


```

plugins {
    id "com.google.protobuf" version "0.8.15"
}

```


And I'm generating DemoUserEvent instances with Java Iterator looking like this:


```

public class UserEventGenerator implements Iterator<DemoUserEvent>,
Serializable {
    transient public final static Faker faker = new Faker();
    ...
    @Override public DemoUserEvent next() {
        return randomCreatedEvent();

     }

     ...

```


I read those two pieces of documentation:
*
https://ci.apache.org/projects/flink/flink-docs-release-1.12/dev/types_serialization.html
*
https://ci.apache.org/projects/flink/flink-docs-release-1.12/dev/custom_serializers.html

And tried the demo app below:

```

import com.twitter.chill.protobuf.ProtobufSerializer;

...

public static void main(String[] args) {
    final StreamExecutionEnvironment flinkEnv =
StreamExecutionEnvironment.getExecutionEnvironment();
    flinkEnv.getConfig().registerTypeWithKryoSerializer(DemoUserEvent.class,
ProtobufSerializer.class);
    flinkEnv.fromCollection(new UserEventGenerator(),
DemoUserEvent.class).print();
}

```

But the serialization mechanism still fails to handle my protobuf class:

11:22:45,822 INFO  org.apache.flink.api.java.typeutils.TypeExtractor
         [] - class live.schema.event.user.v1.DemoUserEvent does not
contain a getter for field payloadCase_
11:22:45,822 INFO  org.apache.flink.api.java.typeutils.TypeExtractor
         [] - class live.schema.event.user.v1.DemoUserEvent does not
contain a setter for field payloadCase_
11:22:45,822 INFO  org.apache.flink.api.java.typeutils.TypeExtractor
         [] - Class class live.schema.event.user.v1.DemoUserEvent
cannot be used as a POJO type because not all fields are valid POJO
fields, and must be processed as GenericType. Please read the Flink
documentation on "Data Types & Serialization" for details of the
effect on performance.

I've also tried this, without success:

```

flinkEnv.getConfig().addDefaultKryoSerializer(DemoUserEvent.class,
ProtobufSerializer.class);

```


I'm using those versions:

```

ext {
    javaVersion = '11'
    flinkVersion = '1.12.1'
    scalaBinaryVersion = '2.12'
}

dependencies {
    compileOnly
"org.apache.flink:flink-streaming-java_${scalaBinaryVersion}:${flinkVersion}"
    implementation ("com.twitter:chill-protobuf:0.9.5") {
        exclude group: 'com.esotericsoftware.kryo', module: 'kryo'
    }
    implementation "com.google.protobuf:protobuf-java:3.14.0"
    implementation 'com.github.javafaker:javafaker:1.0.2'
}

```


Any idea what I should try next?

Thanks in advance!