Apache Kafka create theme from code

Question

As we know, creation Topicin Kafka should be performed in terms of server initialization. There we use the default script ./kafka-topics --zookeeper ..., but what if we need to dynamically create a theme?

Answer 1

Fortunately, Kafka 0.10.1.0brought us this ability. I saw this fascinating feature on board the Confluence Jira, but I could not find any documentation related to this topic, irony, right?

So, I went to the source code and found a way to create themes on the fly. Hope this will be helpful for some of you. Of course, if you have a better solution, please feel free to share it with us.

, .

/** The method propagate topics **/
public List<String> propagateTopics(int partitions, short replication, int timeout) throws IOException {
    CreateTopicsRequest.TopicDetails topicDetails = new CreateTopicsRequest.TopicDetails(partitions, replication);
    Map<String, CreateTopicsRequest.TopicDetails> topicConfig = mTopics.stream()
            .collect(Collectors.toMap(k -> k, v -> topicDetails)); // 1

    CreateTopicsRequest request = new CreateTopicsRequest(topicConfig, timeout); // 2

    try {
        CreateTopicsResponse response = createTopic(request, BOOTSTRAP_SERVERS_CONFIG); // 3
        return response.errors().entrySet().stream()
                .filter(error -> error.getValue() == Errors.NONE)
                .map(Map.Entry::getKey)
                .collect(Collectors.toList()); // 4
    } catch (IOException e) {
        log.error(e);
    }

    return null;
}

1 TopicDetails, . , mTopics - , .

2 Kafka, , - CreateTopicsRequest timeout

3 CreateTopicsResponse

    private static final short apiKey = ApiKeys.CREATE_TOPICS.id;
    private static final short version = 0;
    private static final short correlationId = -1;

private static CreateTopicsResponse createTopic(CreateTopicsRequest request, String client) throws IllegalArgumentException, IOException {
        String[] comp = client.split(":");
        if (comp.length != 2) {
            throw new IllegalArgumentException("Wrong client directive");
        }
        String address = comp[0];
        int port = Integer.parseInt(comp[1]);

        RequestHeader header = new RequestHeader(apiKey, version, client, correlationId);
        ByteBuffer buffer = ByteBuffer.allocate(header.sizeOf() + request.sizeOf());
        header.writeTo(buffer);
        request.writeTo(buffer);

        byte byteBuf[] = buffer.array();

        byte[] resp = requestAndReceive(byteBuf, address, port);
        ByteBuffer respBuffer = ByteBuffer.wrap(resp);
        ResponseHeader.parse(respBuffer);

        return CreateTopicsResponse.parse(respBuffer);
    }

    private static byte[] requestAndReceive(byte[] buffer, String address, int port) throws IOException {
        try(Socket socket = new Socket(address, port);
            DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
            DataInputStream dis = new DataInputStream(socket.getInputStream())
        ) {
            dos.writeInt(buffer.length);
            dos.write(buffer);
            dos.flush();

            byte resp[] = new byte[dis.readInt()];
            dis.readFully(resp);

            return resp;
        } catch (IOException e) {
            log.error(e);
        }

        return new byte[0];
    }

, , .

4 CreateTopicsResponse errors, a Map<String, Errors>, key - , . , , , , , Errors.None, .

Answer 2

10.2.0 CreateTopicsRequest . Builder CreateTopicsRequest. .

CreateTopicsRequest.Builder builder = new CreateTopicsRequest.Builder(topicConfig, timeout, false);
CreateTopicsRequest request = builder.build();