Built-in Provider

Most providers are distributed separately as plugins, but there is one provider that is built into OpenTofu itself. This provider enables the the terraform_remote_state data source.

Because this provider is built in to OpenTofu, you don't need to declare it in the required_providers block in order to use its features (except provider functions). It has a special provider source address, which is terraform.io/builtin/terraform. This address may sometimes appear in OpenTofu's error messages and other output in order to unambiguously refer to the built-in provider, as opposed to a hypothetical third-party provider with the type name "terraform".

There is also an existing provider with the source address hashicorp/terraform, which is an older version of the now-built-in provider. hashicorp/terraform is not compatible with OpenTofu and should never be declared in a required_providers block.

Functions

The built-in provider has additional functions, which can be called after declaring the provider in the required_providers block.

terraform {
  required_providers {
    terraform = {
      source = "terraform.io/builtin/terraform"
    }
  }
}

decode_tfvars

decode_tfvars takes the content of the .tfvars file as a string input and returns a decoded object.

locals {
  content = file("./example_file.tfvars")
  decoded = provider::terraform::decode_tfvars(local.content) # Returns object
}

encode_tfvars

encode_tfvars takes an object and returns the string representation of the object that can be used as the content of the .tfvars file.

locals {
  object = {
    key1 = "value1"
    key2 = "value2"
  }
  encoded = provider::terraform::encode_tfvars(local.object) # Returns string
}

The keys in the object need to be valid identifiers.

encode_expr

encode_expr takes an arbitrary expression and converts it into a string with valid OpenTofu syntax.

locals {
  expression = {
    key1 = "value1"
    key2 = "value2"
  }
  encoded = provider::terraform::encode_expr(local.expression) # Returns string
}