mirror of
https://github.com/opentffoundation/opentf.git
synced 2026-04-22 12:02:11 -04:00
0e004f2377
* website: Update or remove references to legacy provider docs We've finally evicted the last of the legacy provider docs from terraform.io! Let's celebrate by purging all memory of them. The 0.11 docs are now so thoroughly legacy that I don't believe they need a new destination for their provider links, so I just removed those. * website: remove old provider docs index This will require a redirect in the terraform-website repo. * Apply suggestions from code review Co-authored-by: Laura Pacilio <83350965+laurapacilio@users.noreply.github.com> Co-authored-by: Laura Pacilio <83350965+laurapacilio@users.noreply.github.com>
117 lines
3.9 KiB
Markdown
117 lines
3.9 KiB
Markdown
---
|
|
layout: "language"
|
|
page_title: "Data Sources - 0.11 Configuration Language"
|
|
sidebar_current: "docs-conf-old-data-sources"
|
|
description: |-
|
|
Data sources allow data to be fetched or computed for use elsewhere in Terraform configuration.
|
|
---
|
|
|
|
# Data Sources
|
|
|
|
-> **Note:** This page is about Terraform 0.11 and earlier. For Terraform 0.12
|
|
and later, see
|
|
[Configuration Language: Configuring Data Sources](/docs/language/data-sources/index.html).
|
|
|
|
*Data sources* allow data to be fetched or computed for use elsewhere
|
|
in Terraform configuration. Use of data sources allows a Terraform
|
|
configuration to build on information defined outside of Terraform,
|
|
or defined by another separate Terraform configuration.
|
|
|
|
[Providers](./providers.html) are responsible in
|
|
Terraform for defining and implementing data sources. Whereas
|
|
a [resource](./resources.html) causes Terraform
|
|
to create and manage a new infrastructure component, data sources
|
|
present read-only views into pre-existing data, or they compute
|
|
new values on the fly within Terraform itself.
|
|
|
|
For example, a data source may retrieve remote state data from a
|
|
Terraform Cloud workspace, configuration information from Consul, or look up a pre-existing
|
|
AWS resource by filtering on its attributes and tags.
|
|
|
|
Every data source in Terraform is mapped to a provider based
|
|
on longest-prefix matching. For example the `aws_ami`
|
|
data source would map to the `aws` provider (if that exists).
|
|
|
|
This page assumes you're familiar with the
|
|
[configuration syntax](./syntax.html)
|
|
already.
|
|
|
|
## Example
|
|
|
|
A data source configuration looks like the following:
|
|
|
|
```hcl
|
|
# Find the latest available AMI that is tagged with Component = web
|
|
data "aws_ami" "web" {
|
|
filter {
|
|
name = "state"
|
|
values = ["available"]
|
|
}
|
|
|
|
filter {
|
|
name = "tag:Component"
|
|
values = ["web"]
|
|
}
|
|
|
|
most_recent = true
|
|
}
|
|
```
|
|
|
|
## Description
|
|
|
|
The `data` block creates a data instance of the given `TYPE` (first
|
|
parameter) and `NAME` (second parameter). The combination of the type
|
|
and name must be unique.
|
|
|
|
Within the block (the `{ }`) is configuration for the data instance. The
|
|
configuration is dependent on the type; consult the [provider's documentation] (https://registry.terraform.io/browse/providers) for
|
|
details.
|
|
|
|
Each data instance will export one or more attributes, which can be
|
|
interpolated into other resources using variables of the form
|
|
`data.TYPE.NAME.ATTR`. For example:
|
|
|
|
```hcl
|
|
resource "aws_instance" "web" {
|
|
ami = "${data.aws_ami.web.id}"
|
|
instance_type = "t1.micro"
|
|
}
|
|
```
|
|
|
|
### Meta-parameters
|
|
|
|
As data sources are essentially a read only subset of resources they also support the same [meta-parameters](./resources.html#meta-parameters) of resources except for the [`lifecycle` configuration block](./resources.html#lifecycle).
|
|
|
|
## Multiple Provider Instances
|
|
|
|
Similarly to [resources](./resources.html), the
|
|
`provider` meta-parameter can be used where a configuration has
|
|
multiple aliased instances of the same provider:
|
|
|
|
```hcl
|
|
data "aws_ami" "web" {
|
|
provider = "aws.west"
|
|
|
|
# ...
|
|
}
|
|
```
|
|
|
|
See the ["Multiple Provider Instances"](./resources.html#multiple-provider-instances) documentation for resources
|
|
for more information.
|
|
|
|
## Data Source Lifecycle
|
|
|
|
If the arguments of a data instance contain no references to computed values,
|
|
such as attributes of resources that have not yet been created, then the
|
|
data instance will be read and its state updated during Terraform's "refresh"
|
|
phase, which by default runs prior to creating a plan. This ensures that the
|
|
retrieved data is available for use during planning and the diff will show
|
|
the real values obtained.
|
|
|
|
Data instance arguments may refer to computed values, in which case the
|
|
attributes of the instance itself cannot be resolved until all of its
|
|
arguments are defined. In this case, refreshing the data instance will be
|
|
deferred until the "apply" phase, and all interpolations of the data instance
|
|
attributes will show as "computed" in the plan since the values are not yet
|
|
known.
|