Policy as Code

Daniel Foo
4 min readDec 12, 2023

Policy as code (PaC) is a modern approach to managing and enforcing policies within an organization. Instead of relying on traditional, manual methods like written documents and spreadsheets, PaC uses code to define and implement rules and procedures.

PaC can provide numerous benefits:

  • Automation: Policies can be automatically enforced, reducing the risk of human error and inconsistency.
  • Version control: Changes to policies can be tracked and controlled, ensuring that everyone is working with the latest version.
  • Integration: PaC can be integrated with other systems and tools, such as automation frameworks and security platforms.
  • Collaboration: Policies can be easily shared and collaborated on by teams across the organization.
  • Compliance: PaC can help organizations comply with industry regulations and standards.

Policies are written in a high-level programming language, such as YAML or Python. These files are then stored in a version control system and deployed to the relevant systems. When a policy violation occurs, the system automatically generates an alert or takes corrective action.

Policy as Code streamlines policy enforcement by representing rules in code, replacing manual interventions. This automation ensures consistent adherence to standards and minimizes the risk of human error, promoting efficiency in managing complex systems.

PaC seamlessly integrates with Infrastructure as Code practices, extending policy enforcement to code-defined infrastructures. Policies become an inherent part of the deployment process, guaranteeing that the infrastructure aligns with organizational guidelines and regulatory requirements from the outset.

PaC facilitates continuous compliance by conducting automated policy checks at various stages of the development lifecycle. This ongoing validation ensures that systems consistently meet specified rules and compliance standards, reducing the likelihood of post-deployment issues.

Addressing challenges associated with manual compliance, PaC scales effortlessly across dynamic infrastructures. Automation maintains consistency in policy enforcement, adapting seamlessly to the complexities of large-scale deployments without sacrificing accuracy.

Policies expressed as code benefit from version control, enabling organizations to manage changes systematically. Similar to software code, this allows tracking modifications, collaborative policy development, and the ability to revert to previous versions, enhancing governance and auditability.

PaC integrates flawlessly into CI/CD pipelines, embedding policy checks within automated testing and deployment processes. This integration ensures that non-compliant configurations are identified early in the development lifecycle, preventing issues from progressing to production environments.

Automated policy enforcement enhances auditability and reporting capabilities. Organizations can generate comprehensive reports and logs, providing clear insights into compliance status. This transparency aids in demonstrating adherence to industry standards and regulatory requirements.

PaC offers a unified solution for enforcing policies across diverse cloud environments. Whether in multi-cloud or hybrid setups, PaC ensures consistent policy application, promoting standardization and compliance regardless of the cloud service provider.

Policies are articulated using specific languages like Rego, with enforcement carried out by policy engines. This structured approach provides a standardized framework for defining, interpreting, and enforcing policies, enhancing clarity and effectiveness in rule implementation.

Examples of PaC Use Cases:

  • Security: Defining and enforcing access control rules for IT systems.
  • Compliance: Automating compliance checks for regulations like HIPAA or PCI DSS.
  • Infrastructure management: Defining configurations for cloud resources and network devices.
  • Software development: Implementing coding standards and best practices.

Policy as Code Example: Access Control

Here's an example policy written in Rego, used by Open Policy Agent (OPA), to define access control for a simple file system:

package access_control

# Define resources and actions
resource file {
path: string
}
action read(file)
action write(file)

# Define roles and user assignments
role admin {
allow read
allow write
}
role user {
allow read
}
user alice = "alice@example.com" in { admin }
user bob = "bob@example.com" in { user }

# Define policy rules
allow {
user == alice
action == read
}

allow {
user == alice
action == write
file.path startswith "/protected" == false
}

allow {
user == bob
action == read
file.path startswith "/public" == true
}

deny {
true # Deny all other requests
}

This policy defines three resources (files), two actions (read and write), two roles (admin and user), and two users (alice and bob). It also defines three rules:

  • Rule 1: Allows admin users to read and write any file.
  • Rule 2: Allows admin users to write non-protected files.
  • Rule 3: Allows user users to read public files.
  • Rule 4: Denies all other requests.

Popular PaC Tools

  • HashiCorp Sentinel: An open-source framework for policy management.
  • Open Policy Agent (OPA): A general-purpose policy engine used in various applications.
  • Aqua Security: A platform for securing cloud workloads, with features for policy management.
  • Palo Alto Networks Prisma Cloud: A cloud security platform with policy management capabilities.

Getting Started

If you’re interested in getting started with PaC, here are a few steps you can take:

  • Identify your needs: Determine which policies you want to automate and what benefits you hope to achieve.
  • Research PaC tools: Evaluate different options and choose one that best suits your requirements.
  • Develop your policies: Start by writing policies for a few simple cases, and then gradually expand.
  • Integrate with your systems: Configure your chosen PaC tool to work with your existing systems and tools.
  • Test and monitor: Regularly test your policies and monitor for any issues.

Conclusion

Policy as Code is a powerful approach to managing policies that can offer significant benefits for organizations of all sizes.

By adopting Policy as Code, organizations can enhance the efficiency, consistency, and security of their operations while reducing the risk of human error in manual policy enforcement processes.

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Daniel Foo

Director of Engineering at MoneyLion | MBA | Certified Scrum Master | Microsoft Certified Solution Expert