node-sinek

kafka client (consumer + producer) polite out of the box

make it about them, not about you

• Simon Sinek

info

• promise based api
• core builds kafka-node module (checkout for options & tweaking)
• uses ConsumerGroup(s) means your kafka needs to be > 0.9.x ( - 0.10.2+)

offers

• provides an incoming message flow control for consumers
• provides a drain once for consumers
• provides an easy api for producers
• Documentation is still wip; checkout /test/int/Sinek.test.js

install

npm install --save sinek

test

//requires a localhost kafka broker + zookeeper @ localhost:2181
npm test

Usage

const {Kafka, Drainer, Publisher, PartitionDrainer} = require("sinek");

producer (Publisher)

const kafkaClient = new Kafka(ZK_CON_STR, LOGGER);
kafkaClient.becomeProducer([TEST_TOPIC], CLIENT_NAME, OPTIONS);

kafkaClient.on("ready", () => {
    producer = new Publisher(kafkaClient, PARTITION_COUNT); //partition count should be the default count on your brokers partiitons e.g. 30
    
    producer.send(topic, messages, partitionKey, partition, compressionType)
    producer.batch(topic, [])
    
    producer.appendBuffer(topic, identifier, object, compressionType)
    producer.flushBuffer(topic)
    
    //easy api that uses a KeyedPartitioner Type and identifies the
    //target partition for the object's identifier by itself
    //it also brings your payload (object) in perfect shape for 
    //a nicely consumeable topic
    //call producer.flushBuffer(topic) to batch send the payloads
    producer.bufferPublishMessage(topic, identifier, object, version, compressionType)
    producer.bufferUnpublishMessage(topic, identifier, object, version, compressionType)
    producer.bufferUpdatehMessage(topic, identifier, object, version, compressionType)
});

kafkaClient.on("error", err => console.log("producer error: " + err));

consumer (Drainer)

const kafkaClient = new Kafka(ZK_CON_STR, LOGGER);
kafkaClient.becomeConsumer([TEST_TOPIC], GROUP_ID, OPTIONS);

kafkaClient.on("ready", () => {
    consumer = new Drainer(kafkaClient, 1); //1 = thread/worker/parallel count
    
    consumer.drain((message, done) => {
        console.log(message);
        done();
    });
    
    consumer.stopDrain();
    
    consumer.drainOnce((message, done) => {
        console.log(message);
        done();
    }, DRAIN_THRESHOLD, DRAIN_TIMEOUT).then(r => {
        console.log("drain done: " + r);
    }).catch(e => {
        console.log("drain timeout: " + e);
    });
    
    consumer.resetConsumer([TEST_TOPIC]).then(_ => {});
});

kafkaClient.on("error", err => console.log("consumer error: " + err));

consumer (PartitionDrainer) [faster ~ runs a queue per topic partition]

const kafkaClient = new Kafka(ZK_CON_STR, LOGGER);
kafkaClient.becomeConsumer([TEST_TOPIC], GROUP_ID, OPTIONS);

kafkaClient.on("ready", () => {
    consumer = new PartitionDrainer(kafkaClient, 1); //1 = thread/worker/parallel count per partition
    
    //drain requires a topic-name and returns a promise 
    consumer.drain(TEST_TOPIC, (message, done) => {
        console.log(message);
        done();
    }).then(_ => ..).catch(e => console.log(e));
    
    consumer.stopDrain();
    
    //drainOnce requires a topic-name
    consumer.drainOnce(TEST_TOPIC, (message, done) => {
        console.log(message);
        done();
    }, DRAIN_THRESHOLD, DRAIN_TIMEOUT).then(r => {
        console.log("drain done: " + r);
    }).catch(e => {
        console.log("drain timeout: " + e);
    });
    
    consumer.resetConsumer([TEST_TOPIC]).then(_ => {});
});

kafkaClient.on("error", err => console.log("consumer error: " + err));

hints

• interesting options for tweaking consumers

const OPTIONS = {
    sessionTimeout: 12500,
    protocol: ["roundrobin"],
    fromOffset: "latest", //earliest
    fetchMaxBytes: 1024 * 100,
    fetchMinBytes: 1,
    fetchMaxWaitMs: 100,
    autoCommit: true,
    autoCommitIntervalMs: 5000
};

• remove and create topic api will require a special broker configuration or these will just result in nothing at all

drainer.removeTopics([]).then(..)
publisher.createTopics([]).then(..)

• using the .getStats() functions on Drainer, Publisher or PartitionDrainer you can get some valueable insights into whats currently going on in your client

• when using "Drainer" to consume and write upserts into a database that require ACID functionality and a build-up of models/message-payloads you must set the AsyncLimit of new Drainer(.., 1) to "1" or you will have trouble with data integrity

• if your data is spread entity wise above partitions you can use the "PartitionDrainer" to drain multiple partitions at the same time

• the "Publisher" offers a simple API to create such (keyed) partitioned topics

• it is probably a good idea to spawn a Consumer per Topic