Internal Developer Platforms have a well-known dirty secret: most developers do not use them. The platform team builds something genuinely useful — curated pipelines, Terraform modules, Helm charts, GitOps patterns, cost guardrails — wraps it in a service catalogue, adds a web portal, writes runbooks, and waits. Adoption trickles in, usually driven by mandate rather than enthusiasm.

This is not a technology problem. It is a distribution problem. The platform team solved the right problem and delivered it to the wrong address.

As I mentioned in my previous blog post, my first OPA policy was just to catch one simple parameter, if we have in the S3 Terrafom module set the force_destroy = true.

Here’s a simple OPA policy that will catch this dangerous configuration:

package terraform.plan

deny[msg] {
    # Find all resources in the plan
    resource := input.resource_changes[_]
    
    # Check if it's an S3 bucket
    resource.type == "aws_s3_bucket"
    
    # Look for force_destroy in the configuration
    resource.change.after.force_destroy == true
    
    msg := sprintf("S3 bucket '%s' has force_destroy set to true. This is dangerous as it allows bucket deletion even when not empty.", [resource.address])
}

This policy works by:

In the fast-evolving world of cloud computing, managing costs effectively has become a crucial aspect of maintaining a sustainable and profitable business. The “Shift left” paradigm, originally a concept in software development, emphasizes the importance of addressing potential issues early in the development process. When applied to AWS cost optimization and management, this approach ensures that cost considerations are integrated into the earliest stages of the development lifecycle.

By shifting cost management left, organizations can avoid unexpected expenses and optimize their cloud spending proactively. This blog post explores the application of the “Shift left” paradigm to AWS cost optimization, focusing on tools like Open Policy Agent (OPA) policies, Infracost, and Terracost. We will delve into how these tools can help estimate and control costs efficiently, ensuring that your AWS resources are both cost-effective and aligned with your financial goals.