> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/harness-platform/use-harness-platform/governance/policy-as-code/policy-as-code-for-templates.md).

# Policy as Code for Templates

Harness provides governance using Open Policy Agent (OPA), Policy Management, and Rego policies.

You can create a policy and apply it to all [templates](/harness-platform/use-harness-platform/templates/template.md) in your Account, Org, or Project. The policy is evaluated on template-level events:

* **On Save** — evaluated when a template is created or updated.

![Template policy set — entity type and event](/files/ixmXIvbp6IbDnbsokxtS)

For more details, see the [Harness Governance Quickstart](/harness-platform/use-harness-platform/governance/policy-as-code/harness-governance-quickstart.md).

### Prerequisites <a href="#prerequisites" id="prerequisites"></a>

* [Harness Governance Overview](/harness-platform/use-harness-platform/governance/policy-as-code/harness-governance-overview.md)
* [Harness Governance Quickstart](/harness-platform/use-harness-platform/governance/policy-as-code/harness-governance-quickstart.md)
* Policies use the OPA authoring language Rego. For more information, see [OPA Policy Authoring](https://academy.styra.com/courses/opa-rego).

### Step 1: Add a policy <a href="#step-1-add-a-policy" id="step-1-add-a-policy"></a>

1. In Harness, go to **Account Settings** → **Policies** → **New Policy**.
2. Enter a **Name** for your policy and click **Apply**.
3. Add your Rego policy in the editor.

   You can write your own Rego policy or use a sample from the **Library** panel. Select the **Library** tab, choose **Entity: Template** from the dropdown, and pick one of the built-in samples:

   ![Template sample policies in the Library panel](/files/NOL4HKnnL8Nw8Imvh77L)

   Harness ships two sample policies for templates:

   * **Template – Approval:** Ensures that all templates have an approval step.
   * **Template – Allowed Environment:** Ensures that deployments are applied only to allowed environments.

   Below are the Rego policies for both samples.

**Require an approval step in deployment stages**

This policy denies templates that contain a deployment stage without a `HarnessApproval` step. This enforces a review gate before any deployment proceeds.

```
package template

deny[msg] {
  input.template.spec.stages[i].stage.type == "Deployment"
  not stages_with_approval[i]
  msg := sprintf("deployment stage '%s' does not have a HarnessApproval step", [input.template.spec.stages[i].stage.name])
}

stages_with_approval[i] {
  input.template.spec.stages[i].stage.spec.execution.steps[_].step.type == "HarnessApproval"
}
```

**Restrict deployments to allowed environments**

This policy denies templates that deploy to environments outside an approved list, and also blocks templates where the environment reference is missing entirely.

```
package template

deny[msg] {
  stage = input.template.spec.stages[_].stage
  stage.type == "Deployment"
  not contains(allowed_environments, stage.spec.environment.infrastructureDefinitions[i].identifier)
  msg := sprintf("deployment stage '%s' cannot be deployed to environment '%s'", [stage.name, stage.spec.environment.infrastructureDefinitions[i].identifier])
}

deny[msg] {
  stage = input.template.spec.stages[_].stage
  stage.type == "Deployment"
  not stage.spec.environment.environmentRef
  msg := sprintf("deployment stage '%s' has no environment identifier", [stage.name])
}

allowed_environments = ["prod", "stage"]

contains(arr, elem) {
  arr[_] = elem
}
```

4. Click **Save**.

### Step 2: Add the policy to a policy set <a href="#step-2-add-the-policy-to-a-policy-set" id="step-2-add-the-policy-to-a-policy-set"></a>

After creating your policy, add it to a Policy Set before it can be enforced on templates.

1. Go to **Policies** → **Policy Sets** → **New Policy Set**.
2. Enter a **Name** and optional **Description** for the Policy Set.
3. In **Entity type**, select **Template**.
4. In **On what event should the Policy Set be evaluated**, select **On Save**.
5. Click **Continue**.

   <div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p>Existing templates are not automatically evaluated against new policies. Policies are applied only when a template is saved (created or updated).</p></div>
6. In **Policy evaluation criteria**, click **Add Policy**.
7. In the **Select Policy** dialog, choose the scope (**Project**, **Org**, or **Account**) and select the policy you created.

   ![Select a policy for the policy set](/files/AE301WC6MXjq8UBTvaR8)
8. Select the severity and action for policy violations:
   * **Warn & continue** — a warning is displayed if the policy is not met, but the template is saved and you can proceed.
   * **Error and exit** — an error is displayed and the template is not saved if the policy is not met.
9. Click **Apply**, then click **Finish**.
10. The Policy Set is automatically set to **Enforced**. To disable enforcement, toggle off the **Enforced** button.

### Step 3: Apply the policy to a template <a href="#step-3-apply-the-policy-to-a-template" id="step-3-apply-the-policy-to-a-template"></a>

After creating and enforcing your Policy Set, it is automatically evaluated whenever a template is saved.

1. Go to **Account Settings** → **Templates** (or navigate to templates within your Project or Org).
2. Create or edit a template and click **Save**.
3. Based on your selection in the Policy Evaluation criteria:
   * If the template meets the policy, it is saved successfully.
   * If the template violates the policy and the severity is **Warn & continue**, it is saved with a warning.
   * If the template violates the policy and the severity is **Error and exit**, the save is blocked and an error is displayed.

### See also <a href="#see-also" id="see-also"></a>

* [Harness Governance Overview](/harness-platform/use-harness-platform/governance/policy-as-code/harness-governance-overview.md)
* [Policy Samples](/harness-platform/use-harness-platform/governance/policy-as-code/sample-policy-use-case.md)