Creating an ingest plugin
Elasticsearch 5.x introduced the ingest node that allows the modification, via a pipeline, to the records before ingesting in Elasticsearch. We have already seen in Chapter 12, Using the Ingest Module, that a pipeline is composed of one or more processor actions. In this recipe, we will see how to create a custom processor that stores in a field the initial character of another one.
Getting ready
You need an up and running Elasticsearch installation, as we described in the Downloading and installing Elasticsearch recipe in Chapter 1, Getting Started.
Gradle or an integrated development environment (IDE) that supports Java programming with Gradle (version 7.3.x used in the examples), such as Eclipse, Visual Studio Code, or IntelliJ IDEA, is required. Java JDK 17 or above needs to be installed.
The code for this recipe is available in the ch16/ingest_plugin directory.
How to do it...
To create an ingest processor plugin, we need to create the...
