Redis-Tester

This is a project to check connectivity of Redis in different cloud environments.

The project's Docker Image consist of two applications to test redis.

1. Spring Data Redis Application
2. redis-cli Redis client with --tls support without the need for additional certificates.

The spring application shows configuration of a Connection Factory for Redis using Lettuce and not Jedis. The reason for choosing Lettuce is that Jedis currently has no support for Master/Slave mode of Redis. Jedis only supports Redis Cluster Mode and Redis Sentinel Mode. While these work in most cases AWS follows a master slave model. Refer the Spring Redis document Spring Data Redis: Redis Connections for differences.

The project currently supports connecting to 3 different modes of Redis Deployments.

Mode	Description
Standalone	Standard Redis deployment with no replicas/slave. Usually recommended for development environments.
Cluster	Configuration mode suitable for Redis cluster environments.
Master_Replica	Configuration interface suitable for Redis master/slave environments with fixed hosts. This is recommended mode when using AWS Elasticache for Redis

Configuration

The following fields are common to all of the modes and you may leave them blank or not set the at all depending on your requirement.

spring:
  redis:
    username: ${REDIS_USERNAME:default}
    password: ${REDIS_PASSWORD}
    ssl     : ${REDIS_SSL:true}

Based on your redis deployment you can set the mode in the properties file or in your config map.

Property Key	Values
spring.redis.mode	standard, cluster, master_replica

This is not a native spring boot property. This is defined via the additional spring metadata file at src/main/resources/META_INF/additional-spring-configuration-metadata.json and enum definded in com.missakai.redistester.config.RedisMode which is then used by com.missakai.redistester.config.RedisWriteToMasterReadFromReplicaConfiguration when creating the Connection Factory Bean.

Standard Mode

When using the standard mode the following fields must be set. The Connection will be made based on these config.

spring:
  redis:
    host: ${REDIS_HOST}
    port: ${REDIS_PORT:6379}
    mode: standard

Cluster Mode

Cluster mode takes an array of nodes at the spring.redis.cluster.nodes field in format hostname:port

spring:
  redis:
    cluster :
      nodes: ${REDIS_NODES}
    mode: cluster

Master/Replica Mode

This creates a Redis Connection Factory with a Static Master Replica Configuration. This is recommended for a redis model like AWS ElasticCache for Redis. Because AWS has its way of promoting any node as master without a change in the url. This url is provided as Primary Endpoint and Reader Endpoint in the Redis Cluster Description.

Spring Boot's native Redis Properties from spring.redis from the application Property Source. The Configuration for Master is taken from spring.redis.host and spring.redis.port properties The Readers or Slaves are taken from spring.redis.cluster.nodes

spring:
  redis:
    host: ${REDIS_HOST:master.url}
    port    : ${REDIS_PORT:6379}
    cluster :
      nodes: ${REDIS_NODES:replica.url:6379}
    mode: master_replica

Usage

Redis-CLI

To use the redis-cli access the interactive pod console using

kubectl exec <pod_name> -it -- /bin/bash

Spring Application

The application is provided with a Swagger UI which you can execute the API.

To the access the swagger UI first get EXTERNAL-IP of the service by

kubectl get service redis-tester

Then access the swagger through <EXTERNAL-IP>/redis-tester/swagger-ui/