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Visualize Component Dependencies as a Tree

· 3 min read
Erik Osterman
Erik Osterman
Founder @ Cloud Posse

The new atmos list dependencies command renders the dependency relationships between your components as a tree — showing, for every component, both what it depends on and what depends on it. It reads dependencies.components (preferred) and the legacy settings.depends_on, so the output stays consistent with atmos describe dependents.

The Problem​

As infrastructure grows, the relationships between components matter as much as the components themselves. A vpc is a prerequisite for the eks cluster, which is a prerequisite for the alb-controller, and so on. Until now, answering "what would break if I change this?" or "what has to exist before I deploy that?" meant reading atmos describe dependents for one component at a time and stitching the picture together in your head.

The Solution​

atmos list dependencies gives you the whole graph at a glance, as a tree:

atmos list dependencies

Tree output keeps stack context next to the component hierarchy, with component type as secondary metadata on the right:

Dependencies
Stack         Component                 Type
plat-ue2-dev  app-config                terraform
              ├──depends on ↓
              │  ├──▶ dynamodb-table
              │  └──▶ kms-key
              └──required by ↑
                 └──(none)

Triangle markers show edge direction: ▶ means the component depends on that child, and ◀ means that child depends on the selected component.

By default it walks every component and renders both directions — prerequisites and dependents. Scope it to a stack, focus on a single component, pick a direction, or emit structured data instead:

# Limit to one stack
atmos list dependencies --stack plat-ue2-dev

# Focus on a single component in a stack
atmos list dependencies vpc --stack plat-ue2-dev

# Only what the component depends on (its prerequisites)
atmos list dependencies vpc --stack plat-ue2-dev --direction forward

# Only what depends on the component (its dependents)
atmos list dependencies vpc --stack plat-ue2-dev --direction reverse

# Machine-readable output for scripts and CI
atmos list dependencies --format json

Why It Matters​

  • See blast radius before you change anything. --direction reverse answers "what depends on this?" so you know what a change could affect.
  • Understand deployment order. --direction forward shows prerequisites, so you know what must exist first.
  • Consistent with the rest of Atmos. Dependencies come from the same dependencies.components / settings.depends_on sources used by atmos describe dependents, so the tree never contradicts your CI change-detection.

Get Involved​

See the atmos list dependencies reference for all flags and output formats. As always, feedback and ideas are welcome in the Atmos community.