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Abstract Component

Atmos Design Pattern

The Abstract Component pattern marks a component as a blueprint that cannot be deployed directly. Abstract components serve as base configurations that other components inherit from, preventing accidental deployment of incomplete or template configurations.

Use-cases​

Use the Abstract Component pattern when:

  • You have base components that should never be deployed on their own

  • You want to prevent accidental atmos terraform apply on template configurations

  • You need a clear distinction between "blueprints" and "deployable" components

How It Works​

Set metadata.type: abstract to mark a component as non-deployable:

stacks/catalog/vpc/defaults.yaml

components:
  terraform:
    vpc/defaults:
      metadata:
        type: abstract  # Cannot be deployed directly
      vars:
        enabled: true
        nat_gateway_enabled: true
        max_subnet_count: 3

Components that inherit from abstract components are deployable by default:

stacks/deploy/prod.yaml

import:
  - catalog/vpc/defaults

components:
  terraform:
    vpc:
      metadata:
        component: vpc
        inherits:
          - vpc/defaults  # Inherits from abstract component
      vars:
        name: prod-vpc

Error on Deploy Attempt​

If you try to deploy an abstract component:

atmos terraform apply vpc/defaults -s prod

Atmos returns an error:

abstract component 'vpc/defaults' cannot be provisioned since it's explicitly
prohibited from being deployed by 'metadata.type: abstract' attribute

When to Use Abstract vs Real​

TypeUse When
abstractBase configurations, templates, shared defaults
real (default)Deployable components in actual stacks
tip

If you don't specify metadata.type, the component defaults to real and can be deployed.

References​