Add CodeBuild RDS Flyway example

[krimple]

Added example in rds-flyway-migrations that:

• Creates a VPC with two private and public subnets, a NAT and an Internet Gateway
• Installs RDS (Aurora Serverless) listening within the private subnets
• Sets up a CodeBuild project to run a Java Corretto JVM that executes Red Gate's Flyway database migrations tool
  • Configures an ingress rule between the CodeBuild process's security group and the Database Security group on port 5432
  • Uses Secrets Manager to secure the database username, database name and password
• Uses the env > secrets-manager property to encrypt the secrets pulled from the Secrets Manager service in the CodeBuild project

[kgregory-chariot]

I think I'd split this into two CloudFormation templates: one to create the VPC, and one to create the database and CodeBuild. That way, if people already have a VPC that's set up with private/public subnets, they can just use it.

Your deploy.sh can wait for the first stack to complete -- take a look at the deployment script in the "two buckets" example. And you can grab the outputs from one script and automatically set them on the other.

With that said, if you're looking to get this published, then one CF template is fine.

[kgregory-chariot]

I much prefer creating the log group explicitly, then allowing CreateLogStream and PutLogEvents with the group's ARN.

[krimple]

Can I do this in another PR?

[kgregory-chariot]

I just noticed this; is it something that you need for the example, or can you set to false?

[krimple]

I set it so they can explore the example. I didn't get into any detail beyond this comment. But maybe I need some more text in the blog about why it's set and what they can do with it?

[krimple]

Migrated to Serverless V2 Postgres 14

[krimple]

And removed the EnableHttpEndpoint - not relevant in Serverless Aurora V2