PolicyasCode

Policy as code is the practice of expressing governance, security, and compliance policies as machine-readable code that can be versioned, reviewed, tested, and deployed alongside application code. Policies are stored in a policy repository, treated as software artifacts, and enforced automatically by policy engines at run time or during deployment.

Policy engines and languages: The approach typically uses a policy engine such as Open Policy Agent (OPA) with the Rego policy language, or vendor-specific engines like Gatekeeper and Kyverno for Kubernetes, and Terraform Sentinel for Terraform. Policies describe allowed or disallowed actions, resource configurations, or compliance checks, and return a allow/deny decision along with rationale.

Applications and domains: Policy as code is applied across cloud infrastructure provisioning (IaC), container orchestration, and software delivery pipelines. In Kubernetes, Gatekeeper or Kyverno enforce policies on resource manifests; in IaC, Terraform or CloudFormation use policy as code to reject non-compliant configurations; in CI/CD pipelines, policies gate changes before deployment.

Benefits: automated enforcement, consistency, repeatable audits, version-controlled governance, collaboration between development, security, and operations, support for GitOps and continuous compliance.

Challenges: learning curve, performance overhead, test coverage, policy sprawl, dependency on policy runtime, handling secrets, integration complexity, keeping up with evolving regulations.

As a practice in DevSecOps, policy as code seeks to align software delivery with organizational rules and compliance requirements while enabling rapid, safe change. Related concepts include policy languages and engines such as Rego, OPA, Gatekeeper, Kyverno, and Terraform Sentinel.