Compositions execute each function sequentially in the pipeline. Each function has two main tasks:

1. Update the state of resources as they change
2. Send the updated state data back to Crossplane.

Each function receives four key data points:

1. Current state: The real-world status of the composite resource and related resources
2. Target state: The desired status of resources as defined in your configuration
3. Function input: The specific configuration settings for this function
4. Pipeline context: Shared information passed through the function pipeline

This information is available to access a KCL embedded function.

Access function pipeline state

When using KCL embedded functions, these pieces of information are accessible using the built-in option() function in KCL:

• Read the ObservedCompositeResource from option("params").oxr
• Read the ObservedComposedResources from option("params").ocds
• Read the DesiredCompositeResource from option("params").dxr
• Read the DesiredComposedResources from option("params").dcds
• Read the function pipeline’s context from option("params").ctx

You can use these variables to do interesting things, such as extracting data from composed resources or write status to the composite resource.