d/aws_nat_gateway: Fix filtering and reading of tags

[flosell]

Currently, tags can be defined as an argument for the aws_nat_gateway data source and are documented this way but are silently ignored when searching for the NAT Gateway. When reading NAT Gateway details, tag-values aren't populated in terraform. This PR attempts to fix this.

Changes proposed in this pull request:

• filter for given tags when provided as attribute
• read tags-value from API response

Output from acceptance testing:

$ make testacc TEST=./aws TESTARGS='-run=TestAccDataSourceAwsNatGateway'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws -v -parallel 20 -run=TestAccDataSourceAwsNatGateway -timeout 120m
=== RUN   TestAccDataSourceAwsNatGateway
=== PAUSE TestAccDataSourceAwsNatGateway
=== CONT  TestAccDataSourceAwsNatGateway
--- PASS: TestAccDataSourceAwsNatGateway (244.10s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	244.155s

[bflad]

LGTM with one non-blocking comment. Thanks @flosell! 🚀

--- PASS: TestAccDataSourceAwsNatGateway (173.96s)

[bflad]

When using d.Set() with aggregate types (TypeList, TypeSet, TypeMap), we should perform error checking to prevent issues where the code is not properly able to set the Terraform state. e.g.

if err := d.Set("tags", tagstoMap(ngw.Tags)); err != nil {
  return fmt.Errorf("error setting tags: %s", err)
}

Since the tagsToMap() function has well established usage across other resources I won't treat this as a blocker here though. 👍

[bflad]

This has been released in version 1.42.0 of the AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!