Feature request: Make enableAmazonUniqueId work for fargate(ECS)

[TysonAndre]

EC2 is already implemented and uses https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-identity-documents.html , which does not exist for fargate

The IPv4 address 169.254.169.254 is a link-local address and is valid only from the instance.
https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html

https://stackoverflow.com/a/75993784 https://docs.aws.amazon.com/AmazonECS/latest/userguide/task-metadata-endpoint-v4-fargate.html#task-metadata-endpoint-v4-fargate-examples has fields such as dockerId/privateId. dockerId seems the most similar to instanceId.

The environment variable ECS_CONTAINER_METADATA_URI_V4 is set in AWS fargate platform 1.4.0+

DockerId
The Docker ID for the container.
When you use Fargate, the id is a 32-digit hex followed by a 10 digit number.

When querying the ${ECS_CONTAINER_METADATA_URI_V4} endpoint you are returned only metadata about the container itself. The following is an example output.

{
    "DockerId": "cd189a933e5849daa93386466019ab50-2495160603",

Aside: Multiple ECS containers can run on individual EC2 instances. I haven't checked what the endpoint currently does in that case. To preserve existing behavior, 169.254.169.254 (exports.AWS_UNIQUE_ID_URL) could be tried first: https://cloudonaut.io/ecs-vs-fargate-whats-the-difference/