November 2018
Beginner to intermediate
332 pages
8h 14m
English
Content preview from Learning Apache Drill
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Chapter 12. Writing a Format Plug-in
As described in Chapter 8, Apache Drill uses storage and format plug-ins to read data. The storage plug-in connects to a storage system such as Kafka, a database, or a distributed filesystem. The DFS interface is based on the HDFS client libraries and can obtain data from HDFS, Amazon S3, MapR, and so on.
A distributed filesystem contains a wide variety of files (Parquet, CSV, JSON, and so on.) The dfs storage plug-in uses format plug-ins to read data from these files. In this chapter, we explore how to create custom format plug-ins for file formats that Drill does not yet support.
Format plug-ins integrate tightly with Drill’s internal mechanisms for configuration, memory allocation, column projection, filename resolution, and data representation. Writing plug-ins is therefore an “advanced” task that requires Java experience, patience, frequent consultation of existing code, and posting questions on the “dev” mailing list.
Drill provides two ways to structure your plug-in. Here we focus on the “Easy” format plug-in, useful for most file formats, that handles much of the boilerplate for you. It is also possible to write a plug-in without the Easy framework, but it is unlikely you will need to do so.
The Example Regex Format Plug-in
As an example, we’re going to create a format plug-in for any text file format that can be described as a regular expression, or regex. The regex defines how to parse columns from an input record and is defined ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.