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Workflow Environment Variables

· 2 min read
Ben Smith
Ben Smith
Software Engineer

Workflows now support environment variables at both workflow and step levels with hierarchical merging.

What Changed​

You can now define environment variables in workflow YAML files at two levels:

  • Workflow-level: Applied to all steps in the workflow
  • Step-level: Applied to a specific step, overriding workflow-level variables with the same key

Environment variables are merged hierarchically, with step-level values taking precedence over workflow-level values for the same keys.

Example​

workflows:
  deploy:
    description: Deploy with custom environment
    env:
      FOO: bar
      BAZ: workflow-value
    steps:
      - command: echo "$FOO - $BAZ"
        type: shell
        env:
          BAZ: step-value

Running this workflow outputs bar - step-value because:

  • FOO is inherited from the workflow level (bar)
  • BAZ is overridden by the step level (step-value)

Why This Matters​

This feature enables several use cases:

  • Consistent environment setup: Define common variables once at the workflow level
  • Step-specific overrides: Override variables for specific steps without duplicating configuration
  • Integration with external tools: Pass environment variables to shell commands and Terraform

Environment Variable Precedence​

The full precedence order (lowest to highest priority):

  1. System environment variables
  2. Global env from atmos.yaml
  3. Workflow-level env
  4. Step-level env
  5. Auth identity env vars (if identity is specified)

For usage and configuration, see env.

Get Involved​

Have questions or feedback? Join us on Slack or open an issue on GitHub.