Example: Locals

Reduce repetition and build computed values using file-scoped locals.

Learn more about Locals.

What You'll See

• Basic locals — define reusable values within a file
• Dependency resolution — locals reference other locals, resolved via topological sort
• Context access — locals use {{ .settings.X }}, {{ .vars.X }} from the same file
• Sprig functions — pipe syntax like {{ .locals.namespace | upper }}
• Complex values — maps with templates for resource tags
• Multiple components — the same locals shared across components in a file
• File-scoped isolation — dev.yaml and prod.yaml have independent locals

Try It

cd examples/locals

# View resolved locals for the dev stack
atmos describe locals -s dev

# View resolved locals for a specific component
atmos describe locals myapp -s dev

# See how locals flow into component vars
atmos describe component myapp -s dev

# Compare dev vs prod (same patterns, different values)
atmos describe component myapp -s prod

# Worker component appends a suffix to locals
atmos describe component myapp-worker -s dev

Features Demonstrated

1. Basic Locals and References

locals:
  namespace: acme
  environment: development
  name_prefix: "{{ .locals.namespace }}-{{ .locals.environment }}"

Locals are resolved in dependency order — name_prefix waits for namespace and environment.

2. Settings and Vars Access

settings:
  version: v1
vars:
  stage: dev
locals:
  app_version: "{{ .settings.version }}"    # → "v1"
  stage_name: "{{ .vars.stage }}"           # → "dev"

3. Sprig Functions

locals:
  namespace_upper: '{{ .locals.namespace | upper }}'  # → "ACME"

4. Complex Values (Maps)

locals:
  default_tags:
    Namespace: "{{ .locals.namespace }}"
    Environment: "{{ .locals.environment }}"
    Team: "{{ .settings.team }}"
    ManagedBy: Atmos

5. File-Scoped Isolation

Each stack file has its own locals. Even though both dev.yaml and prod.yaml define namespace: acme, they are completely separate — changing one never affects the other. Locals never propagate across file boundaries via imports.

Key Files

File	Purpose
stacks/deploy/dev.yaml	Dev stack: all locals features
stacks/deploy/prod.yaml	Prod stack: same patterns, different values
components/terraform/myapp/main.tf	Mock Terraform component