kafka

kafka —a   distributed  streaming platfform

PUBLISH & SUBSCRIBE

Read and write streams of data like a messaging system.

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PROCESS

Write scalable stream processing applications that react to events in real-time.

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STORE

Store streams of data safely in a distributed, replicated, fault-tolerant cluster.

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It gets used for two broad classes of application:

1. Building real-time streaming data pipelines that reliably get data between systems or applications
2. Building real-time streaming applications that transform or react to the streams of data

First a few concepts:

• Kafka is run as a cluster on one or more servers.
• The Kafka cluster stores streams of records in categories called topics.
• Each record consists of a key, a value, and a timestamp.

Kafka has four core APIs:

• The Producer API allows an application to publish a stream of records to one or more Kafka topics.
• The Consumer API allows an application to subscribe to one or more topics and process the stream of records produced to them.
• The Streams API allows an application to act as a stream processor, consuming an input stream from one or more topics and producing an output stream to one or more output topics, effectively transforming the input streams to output streams.
• The Connector API allows building and running reusable producers or consumers that connect Kafka topics to existing applications or data systems. For example, a connector to a relational database might capture every change to a table.

In Kafka the communication between the clients and the servers is done with a simple, high-performance, language agnosticTCP protocol. This protocol is versioned and maintains backwards compatibility with older version. We provide a Java client for Kafka, but clients are available inmany languages.

Topics —partitions

Producer

Consumer

Stream

connector