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96 lines
2.8 KiB
Plaintext
96 lines
2.8 KiB
Plaintext
---
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page_title: The terraform_data Managed Resource
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description: >-
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Retrieves the root module output values from a Terraform state snapshot stored
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in a remote backend.
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---
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# The `terraform_data` Resource
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The `terraform_data` implements the standard resource lifecycle, but does not directly take any other actions.
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You can use the `terraform_data` resource without requiring or configuring a provider. It is always available through a built-in provider with the [source address](/language/providers/requirements#source-addresses) `terraform.io/builtin/terraform`.
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The `terraform_data` resource is useful for storing values which need to follow a manage resource lifecycle, and for triggering provisioners when there is no other logical managed resource in which to place them.
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## Example Usage (data for `replace_triggered_by`)
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```hcl
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variable "revision" {
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default = 1
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}
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resource "terraform_data" "replacement" {
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input = var.revision
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}
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# This resource has no convenient attribute which forces replacement,
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# but can now be replaced by any change to the revision variable value.
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resource "example_database" "test" {
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lifecycle {
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replace_triggered_by = [terraform_data.replacement]
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}
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}
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```
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## Example Usage (`null_resource` replacement)
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```hcl
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resource "aws_instance" "web" {
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# ...
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}
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# A use-case for terraform_data is as a do-nothing container
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# for arbitrary actions taken by a provisioner.
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resource "terraform_data" "bootstrap" {
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triggers_replace = aws_instance.web.id
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connection {
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host = aws_instance.web.public_ip
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}
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provisioner "remote-exec" {
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inline = [
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"bootstrap-host.sh,
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]
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}
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}
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```
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## Example Usage (force computed value)
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```hcl
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resource "example_resource" "test" {
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name = "foo"
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}
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resource "terraform_data" "example" {
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input = example_resource.test.name
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}
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# This resource has a problem where it will fail during plan if the
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# contains list of resources has not yet been created.
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resource "example_broken_collection" "test" {
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# terraform_data.example.output will stand in as a computed attribute
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# for example_resource.test, which will be unknown until after apply.
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contains = [terraform_data.example.output]
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}
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```
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## Argument Reference
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The following arguments are supported:
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* `input` - (Optional) A value which will be stored in the instance state, and reflected in the `output` attribute after apply.
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* `triggers_replace` - (Optional) A value which is stored in the instance state, and will force replacement when the value changes.
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## Attributes Reference
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In addition to the above, the following attributes are exported:
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* `id` - A string value unique to the resource instance.
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* `output` - The computed value derived from the `input` argument. During a plan where `output` is unknown, it will still be of the same type as `input`.
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