Generic Fetching Resources via Tags

[DrFaust92]

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Description

In many cases it is easier to group resources using tags rather than keeping hard coded lists of resources by their id (which may differ in connection from service to service)

There are multiple feature requests to fetch resource by filter them through tags. A non exhaustive list of those are:

• Lambda datasource that returns multiple functions and allows filters #17701
• Find LB Target Group by Tags #12293
• Add tags argument into aws lb data source #12265

Some of the service do not implement that kind of filtering on the API level which would require building some custom logic to filter that which may differ from resource to resource based on the API response. that may introduce a maintenance burden, and my break in a future release of the AWS SDK/API Change.

Having the ability to fetch a group of resources (from the same type or even for multiple types at once to make code more DRY) may be beneficial for a multitude of case. for example adding cloudwatch log group to a group of resource based on their id instead of iterating a few separate data sources.

AWS has a single generic API to fetch multiple resource types (or single by filter) and filter them by tags. This will make Terraform config more DRY and will reduce amount of API calls (which in turn reduce various throttling and wait issues).

The way to do it is use the Resource Groups Tagging API

New or Affected Resource(s)

• aws_resource_groups_tagging

Potential Terraform Configuration

data "aws_ aws_resourcegroupstagging_resources" "filter" {
  resource_type_filters = ["elbv2:loadbalancer"]

  tag_filters {
    key = "tag_key_1"
  }

  tag_filters {
    key = "tag_key_2"
    values = ["tag_value_1", "tag_value_2"]
  }
}

data "aws_alb" "alb_test_with_arn" {
  for_each = data.aws_resource_groups_tagging.filter.resource_tag_mapping_list

  arn = each.resource_arn
}

References

[bflad]

I personally think this is a good solution to offer since the API support already exists. My only suggestion would be to name it aws_resourcegroupstagging_resources to match our naming standards a little better ("api" and "service" in the service naming we generally have smoothed over) 👍 .

[ghost]

This has been released in version 3.38.0 of the Terraform AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template for triage. Thanks!

[github-actions]

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