Book Image

Mastering Redis

By : Vidyasagar N V, Jeremy Nelson
Book Image

Mastering Redis

By: Vidyasagar N V, Jeremy Nelson

Overview of this book

Redis is the most popular, open-source, key value data structure server that provides a wide range of capabilities on which multiple platforms can be be built. Its fast and flexible data structures give your existing applications an edge in the development environment. This book is a practical guide which aims to help you deep dive into the world of Redis data structure to exploit its excellent features. We start our journey by understanding the need of Redis in brief, followed by an explanation of Advanced key management. Next, you will learn about design patterns, best practices for using Redis in DevOps environment and Docker containerization paradigm in detail. After this, you will understand the concept of scaling with Redis cluster and Redis Sentinel , followed by a through explanation of incorporating Redis with NoSQL technologies such as Elasticsearch and MongoDB. At the end of this section, you will be able to develop competent applications using these technologies. You will then explore the message queuing and task management features of Redis and will be able to implement them in your applications. Finally, you will learn how Redis can be used to build real-time data analytic dashboards, for different disparate data streams.
Table of Contents (18 chapters)
Mastering Redis
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Using KEYS and ARGV with Redis


We have already been using the keys and optional arguments that are accessible as the KEYS and ARGV Lua tables in our Lua server-side scripts in Redis. To illustrate this, we'll run ninth_script that echoes back a Lua table with the KEYS and ARGS variables as members to the Redis client:

>>> ninth_script = """--[[ Returns all KEYS and ARGV as members of a Lua Table ]]--
return {KEYS[1], KEYS[2], ARGV[1], ARGV[2]}"""
>>> keys_and_args = ["Airline:1", "Airline:2", "Singapore Airlines", "Southwest"]
>>> datastore.eval(ninth_script, 2, *keys_and_args)
[b'Airline:1', b'Airline:2', b'Singapore Airlines', b'Southwest']

We can refactor this script—now called tenth_script—so that instead of requiring explicit keys for the Lua table, we can create a for loop that iterates through all of the values in KEYS and ARGV and returns the resulting Lua table:

>>> tenth_script = """--[[ Demostrates creating a Lua table with both KEYS and ARGV...