Book Image

Advanced Elasticsearch 7.0

By : Wai Tak Wong
Book Image

Advanced Elasticsearch 7.0

By: Wai Tak Wong

Overview of this book

Building enterprise-grade distributed applications and executing systematic search operations call for a strong understanding of Elasticsearch and expertise in using its core APIs and latest features. This book will help you master the advanced functionalities of Elasticsearch and understand how you can develop a sophisticated, real-time search engine confidently. In addition to this, you'll also learn to run machine learning jobs in Elasticsearch to speed up routine tasks. You'll get started by learning to use Elasticsearch features on Hadoop and Spark and make search results faster, thereby improving the speed of query results and enhancing the customer experience. You'll then get up to speed with performing analytics by building a metrics pipeline, defining queries, and using Kibana for intuitive visualizations that help provide decision-makers with better insights. The book will later guide you through using Logstash with examples to collect, parse, and enrich logs before indexing them in Elasticsearch. By the end of this book, you will have comprehensive knowledge of advanced topics such as Apache Spark support, machine learning using Elasticsearch and scikit-learn, and real-time analytics, along with the expertise you need to increase business productivity, perform analytics, and get the very best out of Elasticsearch.
Table of Contents (25 chapters)
Free Chapter
1
Section 1: Fundamentals and Core APIs
8
Section 2: Data Modeling, Aggregations Framework, Pipeline, and Data Analytics
13
Section 3: Programming with the Elasticsearch Client
16
Section 4: Elastic Stack
20
Section 5: Advanced Features

Integration with the Bollinger Band

In the last section, we introduced the workflow of buildAnalyticsModel. After we insert/update the ETF data to the cf_etf_history_data index, we compute the data for the Bollinger Band. Let's recall the details to compute the Bollinger Band from the Operational data analytics section of Chapter 10, Using Elasticsearch for Exploratory Data Analysis, to work on Java programming. The step-by-step instructions are as follows:

  1. Collect all the related documents by performing a search operation: symbol and period are given by the user. startDate and endDate can be derived from the period. We have learned how to use Elasticsearch's high-level REST client to build a SearchRequest object in the Java high-level REST client section in Chapter 11, Elasticsearch from Java Programming. The following code block is extracted from the getBollingerBand...