jorgemarcial/workshop-redis

workshop redis

What is redis?

• In-memory data structure store, used as a database, cache and message broker.
• Key / value database.
• Different levels of on-disk persistence.

Why redis?

• Not just a cache.
• Multiple datatypes.
• Pub-sub model.
• Cluster mode for high availability.
• Perfectly works in cloud: AWS Elasticache, Azure Redis Cache and Memorystore (Google Cloud).

Data types

Remember you need in our local:

# redis
# redis-cli 
# npm / nodejs

# install dependencies
npm install

Overview

• Redis instance has 16 databases, DONT NEED PREFIX IN KEYS

redis-cli -n {database_number}

• Debugging from cli

redis-cli monitor

• Main commands: KEYS / DEBUG / SCAN / TYPE / EXPIRATE

String

• Basic data type
• Main commands: set / get

node examples/datatypes/string.js

List

• Arrays of strings
• Main commands : lpush / lrange / lpop

node examples/datatypes/list.js

Set

• Unique and unordered collection of strings
• Main commands: sadd / smember / srem / sscan

node examples/datatypes/set.js

Hash

• Maps between string fields and string values
• Perfect data type to represent objects
• Main commands: hset / hmset / hget / hgetall / hscan

node examples/datatypes/hash.js

Sorted Sets

• Similarly to Redis Sets, non repeating collections of Strings.
• Every member of a Sorted Set is associated with score
• Main commands: zadd / zrangebyscore

node examples/datatypes/sorted-set.js

Streams

• New data type from Redis 5
• Goal handle large amount of data (example: chat history, logs, etc)
• Main commands: xadd / xread

node examples/datatypes/stream.js

Transactions

COMMANDS MULTI, EXEC, DISCARD and WATCH

• They allow the execution of a group of commands in a single step
• All the commands in a transaction are serialized and executed sequentially.
• Atomicity (either all occur or nothing occurs)

node examples/transactions/multi-exec.js

LUA SCRIPT

• You can encapsulate some complex operations in a script and your data layer will perform the atomic

node examples/transactions/rewards.js
node examples/transactions/lua-script.js

Message Queues

• PUBLISH / SUBSCRIBE

pros

• Memory efficiency
• Group messagingsS
• Examples: notifications, chats, etc.

cons

• High chance loss message

node pubsub.js

• BRPOPLPUSH / RedisSMQ

• Message only will be consumed by one consumer
• Less memory efficiency

node examples/queues/create.js
node examples/queues/producer.js
node examples/queues/consumer.js

Everyone should read

https://redis.io/topics/introduction

https://dzone.com/articles/how-redis-is-used-in-practice

https://www.bogotobogo.com/DevOps/Redis/Redis_vs_Memcached.php

https://matt.sh/what-is-redis

https://matt.sh/introduction-to-redis-data-types

https://www.compose.com/articles/a-quick-guide-to-redis-lua-scripting/

https://medium.com/@anvannguyen/redis-message-queue-rpoplpush-vs-pub-sub-e8a19a3c071b