operation

Operations Example

This example demonstrates using function-python with Crossplane Operations to check SSL certificate expiry for websites referenced in Kubernetes Ingress resources.

Files

• operation.yaml - The Operation that checks certificate expiry
• functions.yaml - Function definition for local development
• ingress.yaml - Sample Ingress resource to check
• rbac.yaml - RBAC permissions for Operations to access Ingress resources
• README.md - This file

Testing

Since Operations are runtime-only (they can't be statically rendered), you can test this example locally using the new crossplane alpha render op command.

Prerequisites

1. Run the function in development mode:

   hatch run development

2. In another terminal, render the operation:

   crossplane alpha render op operation.yaml functions.yaml --required-resources . -r

The -r flag includes function results in the output, and --required-resources . tells the command to use the ingress.yaml file in this directory as the required resource.

What it does

The Operation:

1. Reads the Ingress resource specified in requirements.requiredResources
2. Extracts the hostname from the Ingress rules (google.com in this example)
3. Fetches the SSL certificate for that hostname
4. Calculates expiry information (days until expiration)
5. Annotates the Ingress with certificate monitoring annotations
6. Returns status information in the Operation's output field

This pattern is useful for:

• Certificate monitoring and alerting
• Compliance checking
• Automated certificate renewal workflows
• Integration with monitoring tools that read annotations

Function Details

The operation function (operate()) demonstrates key Operations patterns:

• Required Resources: Accessing pre-populated resources via request.get_required_resources(req, "ingress")
• Resource Updates: Using rsp.desired.resources to update existing resources
• Operation Output: Using rsp.output.update() for monitoring data
• Server-side Apply: Crossplane applies the changes with force ownership