Aws-cdk: allow to create FargateService with imported TaskDefinition

[pahud]

FargateService requires the TaskDefinition type and using existing task definition is not allowed.

https://github.com/aws/aws-cdk/blob/c304d24d313ef61d8cc6b110df9ba4f3f441d133/packages/%40aws-cdk/aws-ecs/lib/fargate/fargate-service.ts#L17

Use Case

Becasue cloudformation is missing some features such as TaskDefinition with EFS support, we may create our own task definition with CLI or console and allow CDK to create Fargate service by importing the existing task definition.

Proposed Solution

Maybe we can simply use ITaskDefinition instead?

The drawback is we will not be able to check the defaultContainer here.

https://github.com/aws/aws-cdk/blob/c304d24d313ef61d8cc6b110df9ba4f3f441d133/packages/%40aws-cdk/aws-ecs/lib/fargate/fargate-service.ts#L167-L169

Other

• [ ] :wave: I may be able to implement this feature request
• [ ] :warning: This feature might incur a breaking change

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This is a :rocket: Feature Request

[pahud]

related to https://github.com/aws/aws-cdk/issues/6240

[kennu]

I also need this feature, to be able to define the TaskDefinition externally to support EFS volumes for Fargate.