Output Variables

Output variables are like return values for a module. They are declared using the keyword output. Output variables can expose certain information. They can be used by a root module to output certain values after running the terraform apply/output command, or by a child module to expose a subset of its resource attributes to a parent module.

output "ecs_address" {
  description = "The private IP address of my ECS"
}

The label immediately after the output keyword is the name, which must be a valid identifier. The output block contains the following arguments:

• value (mandatory): value of the output variable. Any valid expression is allowed as an output value.

• description: describes the usage of an output variable.

  output "vpc_id" {
    description = "Check out the VPC ID"
  }

• sensitive: marks output variables as sensitive and hides the output variable values on the CLI.

  output "vpc_id" {
    description = "Check out the VPC ID"
    sensitive   = true
  }
  
  $ terraform output
  vpc_id = <sensitive>

  Note: Output variables marked as sensitive are automatically hidden during output, but their output values can still display in the following ways:

  • The values of output variables are recorded in the state file and are visible to anyone who can access the file.
  • The sensitive output variable values in a child module can be invoked by its parent module and displayed on the CLI after being referenced by the related outputs and resources of the parent module.

• depends_on: specifies the dependency of an output variable. Since output variables are only a means of exporting data, you do not need to set the dependencies between output variables and other resources or data.