4. Data Source

Data sources are intended for infrastructure which already exists. As such, they are not created, updated or destroyed by Terraform, but rather simply referenced. Think of them as read-only.

Syntax

Data sources are declared similarly to resources, but use the data keyword. Like this:

data "data_source_type" "data_source_instance" {
    # ... configuration options ...
}

They data_source_type comes from your provider and data_source_instance is the name or label you use for the instance and must be unique.

For example:

data "akamai_group" "my_group" {
     group_name   = "My Group"
     contract_id  = "1-2AB34C"
}

Here, we are looking for the akamai_group named "My Group", which can be found in the given contract. This is useful as we may wish to use the group ID but only know its name.

Referencing Data Sources

References to data source IDs always start with data, and then the type and instance names separated by .. The format is as follows:

data.<data source type>.<data source instance>.<instance attribute>

For example:

resource "akamai_property" "example" {
    group_id    = data.akamai_group.my_group.id
    # ... other configuration ...
}

Here we cross-reference the id attribute of the my_group instance of the akamai_group data source, in order to use it in our akamai_property resource. References can be used in different types of Terraform blocks such as modules and outputs.

Exercise