---
page_title: Data Sources
description: >-
  Data sources allow data to be fetched or computed for use elsewhere in local variables and
  build sources configuration. Use of data sources
  allows a Builder to make use of information defined outside of Packer.
---

# Data Sources

-> **Note:** Data Sources is a feature included in Packer 1.7 and later.

Data sources allow data to be fetched or computed for use elsewhere in [locals](/packer/docs/templates/hcl_templates/blocks/locals) and
[sources](/packer/docs/templates/hcl_templates/blocks/source) configuration.
Use of data sources allows a Builder to make use of information defined outside of Packer.

# Using Data Sources

A data source is declared using a data block, and the configuration looks like the following:

```hcl
data "amazon-ami" "example" {
    filters = {
        virtualization-type = "hvm"
        name = "ubuntu/images/*ubuntu-xenial-16.04-amd64-server-*"
        root-device-type = "ebs"
    }
    owners = ["099720109477"]
    most_recent = true
}
```

A data block requests that Packer read from a given data source ("amazon-ami") and export the result under the given
local name ("example"). The name is used to refer to this data source from elsewhere in the same Packer configuration.

The data block creates a data instance of the given _type_ (first block label) and _name_ (second block label).
The combination of the type and name must be unique within a configuration.

Within the block (the `{ }`) is the configuration for the data instance. The configuration is dependent on the data source type,
and is documented for each data source. For example the configuration of the `amazon-ami` data source can be found at [plugins/datasources/amazon/ami](/packer/plugins/datasources/amazon/ami#configuration-reference).

A data source can output one or more attributes, which can be used by adding their key name to the data source unique
identifier, like `data.<TYPE>.<NAME>.<ATTRIBUTE>`.

The output from the `amazon-ami.example` above can be accessed as follows:

Output data:

```
"data.amazon-ami.example" {
  id = "ami12345"
  name = "MyAMI"
  creation_date = "01/01/2021"
  owner = "123456789"
  owner_name = "Some Name"
  tags = {"tag1": "value"}
}
```

Usage:

```hcl
// in a local
locals {
  source_ami_id = data.amazon-ami.example.id
  source_ami_name = data.amazon-ami.example.name
 }
```

```hcl
// in a source
source "amazon-ebs" "basic-example" {
  source_ami = locals.source_ami
  // ...
}
```

## Known Limitations
`@include 'datasources/local-dependency-limitation.mdx'`


## Related

- The list of available data sources can be found in the [data sources](/packer/docs/datasources)
  section.
- Create your own [custom data source](/packer/docs/plugins/creation/custom-datasources) !
