Book Image

Learning Apache Flink

By : Tanmay Deshpande
Book Image

Learning Apache Flink

By: Tanmay Deshpande

Overview of this book

<p>With the advent of massive computer systems, organizations in different domains generate large amounts of data on a real-time basis. The latest entrant to big data processing, Apache Flink, is designed to process continuous streams of data at a lightning fast pace.</p> <p>This book will be your definitive guide to batch and stream data processing with Apache Flink. The book begins with introducing the Apache Flink ecosystem, setting it up and using the DataSet and DataStream API for processing batch and streaming datasets. Bringing the power of SQL to Flink, this book will then explore the Table API for querying and manipulating data. In the latter half of the book, readers will get to learn the remaining ecosystem of Apache Flink to achieve complex tasks such as event processing, machine learning, and graph processing. The final part of the book would consist of topics such as scaling Flink solutions, performance optimization and integrating Flink with other tools such as ElasticSearch.</p> <p>Whether you want to dive deeper into Apache Flink, or want to investigate how to get more out of this powerful technology, you’ll find everything you need inside.</p>
Table of Contents (17 chapters)
Learning Apache Flink
About the Author
About the Reviewers
Customer Feedback

Data sources

Sources are places where the Flink program expects to get its data from. This is a second step in the Flink program's anatomy. Flink supports a number of pre-implemented data source functions. It also supports writing custom data source functions so anything that is not supported can be programmed easily. First let's try to understand the built-in source functions.


DataStream API supports reading data from a socket. You just need to specify the host and port to read the data from and it will do the work:

socketTextStream(hostName, port); 

You can also choose to specify the delimiter:


You can also specify the maximum number of times the API should try to fetch the data:

socketTextStream(hostName,port,delimiter, maxRetry) 


You can also choose to stream data from a file source using file-based source functions in Flink. You can use readTextFile(String path) to stream data from a file specified in the path. By default...