redis

ElastiCache Redis in AWS provides managed Redis instances for caching and session storage. Stackattack creates Redis clusters with secure networking, parameter groups, and proper security group configuration.

import * as saws from "@stackattack/aws";

const ctx = saws.context();
const network = saws.vpc(ctx);
const cache = saws.redis(ctx, {
  network: network.network("private")
});

export const redisUrl = cache.url;

Usage

After deploying a Redis cluster, you can connect to it using:

Direct Connection:

# Connect using redis-cli from an EC2 instance in the same VPC
redis-cli -u redis://your-redis-endpoint.cache.amazonaws.com:6379/0

# Test basic operations
SET mykey "Hello Redis"
GET mykey

Application Code:

import Redis from "ioredis";

const redis = new Redis({
  host: "your-redis-endpoint.cache.amazonaws.com",
  port: 6379,
  retryDelayOnFailover: 100,
  maxRetriesPerRequest: 3
});

await redis.set("session:123", JSON.stringify({ userId: 456 }));
const session = await redis.get("session:123");

Related Components

Redis clusters work together with other Stackattack components:

• vpc - Provides secure private networking for Redis access

Costs

ElastiCache Redis costs are fixed hourly charges based on node type:

• Instance costs - The default cache.t4g.micro costs ~$11.68/month if running 24/7. Larger instances provide more memory and performance:

  • cache.t4g.small (~$23.36/month) - 1.37GB RAM
  • cache.r7g.large (~$146.83/month) - 13.07GB RAM
  • cache.r7g.xlarge (~$293.66/month) - 26.32GB RAM

• Backup storage - Automatic snapshots are free within the allocated memory size. Additional backup storage is ~$0.085/GB/month.

• Data transfer - Connections within the same VPC are free. Cross-AZ data transfer costs ~$0.01/GB in each direction.

• Multi-AZ - If you enable replication groups for high availability, you pay for each additional node.

Memory requirements planning:

• Session storage: ~1KB per user session
• Application caching: Depends on cache hit ratio and object sizes
• Database query caching: Can range from MBs to GBs depending on query complexity

Cost optimization strategies:

• Start small; use cache.t4g.micro for development and small applications. Unless you’re using redis as a primary data store or a cache for a large amount of data, there’s a good chance you won’t need anything bigger than that for some time.
• Monitor memory utilization and scale instance type as needed
• Set appropriate TTL values to prevent memory leaks
• Use Redis eviction policies like allkeys-lru for automatic cleanup

See ElastiCache Pricing for current rates.

redis

Creates an ElastiCache Redis cluster with security group, parameter group, and subnet group.

function redis(ctx: Context, args: RedisArgs): RedisOutput

Parameters

• ctx (Context) - The context for resource naming and tagging
• args (RedisArgs) - Configuration arguments for the Redis cluster

Returns

• (RedisOutput) - Creates an ElastiCache Redis cluster with security group, parameter group, and subnet group.

Interfaces

RedisArgs

Configuration arguments for creating an ElastiCache Redis cluster.

Properties

• availabilityZone? (Input<string>) - Specific availability zone for the cluster
• engine? (Input<string>) - ElastiCache engine type (defaults to “redis”)
• engineVersion? (Input<string>) - Engine version (defaults to “6.x”)
• network (Network) - The network configuration (VPC and subnets) for the Redis cluster
• nodeType? (Input<string>) - Instance type for cache nodes (defaults to “cache.t4g.micro”)
• noPrefix? (boolean) - Whether to skip adding a prefix to the resource name
• numNodes? (Input<number>) - Number of cache nodes in the cluster (defaults to 1)
• parameters? (Record<string, Input<string>>) - Custom parameters for the parameter group
• port? (Input<number>) - Port number for Redis connections (defaults to 6379)
• sourceSecurityGroupId? (Input<string>) - Security group ID that should be allowed to access the cluster

RedisOutput

Output from creating a Redis cluster, containing the instance and connection URL.

Properties

• instance (Cluster) - The ElastiCache cluster resource
• url (Output<string>) - Connection URL for the Redis cluster