[elasticache] More metrics/alarming support for Redis

[echeung-amzn]

Relevant metrics:

• DatabaseMemoryUsagePercentage
• CurrConnections
• StringBasedCmdsLatency

Docs:

• https://aws.amazon.com/blogs/database/monitoring-best-practices-with-amazon-elasticache-for-redis-using-amazon-cloudwatch
• https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/CacheMetrics.Redis.html

[voho]

We have to decide whether we want to always show these metrics (e.g. in an extra row) or add a flag to show them (e.g. enableDetailedMetrics?). We already know the engine type, since it is a monitoring parameter.

[matiaslagoevia]

Hello, I'd like to tackle this issue if possible. I'd be happy to groom & work on the issue with assistance, thanks!

[echeung-amzn]

Sure!

The relevant files you'll likely be touching include:

• https://github.com/cdklabs/cdk-monitoring-constructs/blob/main/lib/monitoring/aws-elasticache/ElastiCacheClusterMetricFactory.ts: functions for getting the relevant metrics
• https://github.com/cdklabs/cdk-monitoring-constructs/blob/main/lib/monitoring/aws-elasticache/ElastiCacheClusterMonitoring.ts: where the metrics are used for dashboard and alarm purposes
• https://github.com/cdklabs/cdk-monitoring-constructs/tree/main/test/monitoring/aws-elasticache: correponding test files

The existing code should be representative of the relevant patterns with other metrics, but let us know if you have any questions!