New List Configuration and Stack Filtering

The atmos list components command now correctly shows unique component definitions, supports stack filtering, and uses a new dedicated configuration namespace.

What Changed

The atmos list components command behavior has been restored to its original intent:

• list components - Shows unique component definitions (deduplicated across all stacks)
• list instances - Shows all component instances (one entry per component+stack pair)

Previously, both commands were returning the same data (component instances), which was confusing.

New: Filter Components by Stack

You can now filter which stacks to consider when listing unique components using the --stack flag with glob patterns:

# List components that exist in any dev stack
atmos list components --stack "*-dev"

# List components in a specific environment
atmos list components --stack "plat-ue2-*"

# List components across all production stacks
atmos list components --stack "*-prod"

This is useful when you want to see what components are defined for a particular environment or stage without seeing the full list across all stacks.

New Configuration Namespace

We've introduced a cleaner configuration structure for list commands with separate settings for list components and list instances:

# atmos.yaml
list:
  # Configuration for "atmos list components"
  # Shows unique component definitions (deduplicated)
  components:
    format: table
    columns:
      - name: Component
        value: "{{ .component }}"
      - name: Type
        value: "{{ .type }}"
      - name: Stacks
        value: "{{ .stack_count }}"

  # Configuration for "atmos list instances"
  # Shows component instances (one per component+stack pair)
  instances:
    format: table
    columns:
      - name: Stack
        value: "{{ .stack }}"
      - name: Component
        value: "{{ .component }}"
      - name: Type
        value: "{{ .type }}"
      - name: Tenant
        value: "{{ .vars.tenant }}"
      - name: Environment
        value: "{{ .vars.environment }}"

Available Fields

For list components (unique component fields):

• {{ .component }} - Component name
• {{ .type }} - Component type (terraform, helmfile, packer)
• {{ .stack_count }} - Number of stacks using this component
• {{ .component_folder }} - Path to component folder

For list instances (per-instance fields):

• All unique component fields above, plus:
• {{ .stack }} - Stack name
• {{ .vars.* }} - Any variable from the component (tenant, environment, stage, region, etc.)
• {{ .status }} - Component status indicator

Backward Compatibility

Existing configurations using components.list.columns continue to work for list instances. The precedence is:

For list instances:

1. --columns CLI flag
2. list.instances.columns (new)
3. components.list.columns (deprecated, backward compat)
4. Default columns

For list components:

1. --columns CLI flag
2. list.components.columns (new)
3. Default columns (Component, Type, Stacks)

Note: The old components.list.columns does not fall back for list components because those columns were designed for per-instance data (with stack-specific fields).

Example Output

atmos list components now shows unique components:

Component             Type        Stacks
vpc                   terraform   6
vpc-flow-logs-bucket  terraform   6

atmos list components --stack "*-dev" filters to dev stacks:

Component             Type        Stacks
vpc                   terraform   2
vpc-flow-logs-bucket  terraform   2

atmos list instances continues to show all instances:

Stack           Component             Type        ...
plat-ue2-dev    vpc                   terraform   ...
plat-ue2-dev    vpc-flow-logs-bucket  terraform   ...
plat-ue2-prod   vpc                   terraform   ...
...

Migration

Update your atmos.yaml from:

components:
  list:
    columns: [...]

To:

list:
  instances:
    columns: [...]

And optionally add a list.components section to customize the unique components output.