Book Image

ElasticSearch Server

Book Image

ElasticSearch Server

Overview of this book

ElasticSearch is an open source search server built on Apache Lucene. It was built to provide a scalable search solution with built-in support for near real-time search and multi-tenancy.Jumping into the world of ElasticSearch by setting up your own custom cluster, this book will show you how to create a fast, scalable, and flexible search solution. By learning the ins-and-outs of data indexing and analysis, "ElasticSearch Server" will start you on your journey to mastering the powerful capabilities of ElasticSearch. With practical chapters covering how to search data, extend your search, and go deep into cluster administration and search analysis, this book is perfect for those new and experienced with search servers.In "ElasticSearch Server" you will learn how to revolutionize your website or application with faster, more accurate, and flexible search functionality. Starting with chapters on setting up your own ElasticSearch cluster and searching and extending your search parameters you will quickly be able to create a fast, scalable, and completely custom search solution.Building on your knowledge further you will learn about ElasticSearch's query API and become confident using powerful filtering and faceting capabilities. You will develop practical knowledge on how to make use of ElasticSearch's near real-time capabilities and support for multi-tenancy.Your journey then concludes with chapters that help you monitor and tune your ElasticSearch cluster as well as advanced topics such as shard allocation, gateway configuration, and the discovery module.
Table of Contents (17 chapters)
ElasticSearch Server
Credits
About the Authors
Acknowledgement
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
Index

Using scripts


ElasticSearch has a few functionalities where scripts can be used. You've already seen examples such as updating documents, filtering, and searching. Regardless of the fact that this seems to be advanced, we will take a look at the possibilities given by ElasticSearch. Looking into any request that use scripts, we can spot several fields:

  • script: This field contains the script code.

  • lang: This field informs the engine which language is used. If it is omitted, ElasticSearch assumes mvel.

  • params: This is an object containing parameters. Every defined parameter is available for script by its name. By using parameters, we can write cleaner code. Due to caching, code with parameters performs better than code with embedded constant values.

Available objects

During the execution of the script, ElasticSearch exposes several objects. The ones available for operations connected with searching are as follows:

  • doc (also available as _doc): This is an instance of the org.elasticsearch.search...