Locals Block

The locals block allows defining computed values for the workspace. Unlike variable blocks, locals cannot be overridden from the command line—they are computed from other values (variables, predefined values, or expressions).

Scope: Workspace locals are available to all projects in the workspace and can be referenced in workspace-level blocks (extensions, targets) and project-level blocks.

Usage

Locals are referenced using the local.<identifier> syntax. They can reference:

• Workspace variables: var.config
• Predefined variables: terrabuild.branch_or_tag
• Other locals: local.other_local
• Functions and expressions

Example Usage

Simple Local

locals {
  app_name = "terrabuild"
  version = "1.0.0"
}

Computed from Variables

variable environment {
  default = "dev"
}

locals {
  image_tag = var.environment + "-" + terrabuild.branch_or_tag
  registry = "ghcr.io/myorg"
}

Complex Expressions

variable config {
  default = "Debug"
}

locals {
  # Build image tag from multiple sources
  full_tag = var.config + "-" + terrabuild.branch_or_tag
  
  # Registry path
  registry = "ghcr.io/myorg"
  
  # Computed from other locals
  base_image = local.registry + "/base:" + local.full_tag
}

Using in Extensions

locals {
  dotnet_version = "8.0"
  node_version = "22"
}

extension @dotnet {
  container = "mcr.microsoft.com/dotnet/sdk:" + local.dotnet_version
}

extension @npm {
  container = "node:" + local.node_version
}

Multiple Locals Blocks

You can define multiple locals blocks in the same file. All identifiers must be unique across all blocks:

locals {
  app_name = "api"
}

locals {
  version = "1.0.0"
}

# Both can be used:
# local.app_name and local.version