(aws-ecs): Support specifying latest revision of task family in service instead of specific revision

[luxaritas]

Describe the feature

CloudFormation allows you to specify a task family without a revision when creating a service to have it use the latest active task definition. However, when passing a task definition to a service in the CDK, it always uses the ARN of the specific revision

Use Case

I use the ECS deployment action in CodePipeline to automatically create a new task revision on deployment, as well as storing the image ID in an SSM parameter so that if I update the task definition CDK-side, it uses the correct (most recent) image ID. However, if the service needs to be redeployed without changing the task definition, the service will be redeployed with the last revision of the task that was deployed via CDK/CFN, which rolls back the image (which is unacceptable as it could cause critical application failures).

Proposed Solution

Add a parameter to the service constructor called something like taskRevision, allowing it to specify a specific revision or latest, using that revision and the family from the task definition instead of the .

An alternative could be #7863 (where you create the task definition, construct an arn from that, import the resource, then pass that instead of the task def), but in this case we already have the task definition we want to use, so that seems to require more workarounds.

Other Information

Yes, I understand the recommended approach is to have the pipeline redeploy the CDK stack with a parameter specifying the image as a means to keep the CDK app itself deterministic, however my position is that is substantial added complexity (namely, in the mental gymnastics needed for someone to understand it) for little concrete benefit - the end result is the same, and this approach means that there is truly no drift. Additionally the current behavior can cause critical application failures if an old image is accidentally deployed.

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.93.0

Environment details (OS name and version, etc.)

N/A

[pahud]

Makes sense to me. Thank you for your feedback and potential pull request for it.

[github-actions]

⚠️COMMENT VISIBILITY WARNING⚠️

Comments on closed issues are hard for our team to see.
If you need more assistance, please either tag a team member or open a new issue that references this one.
If you wish to keep having a conversation with other community members under this issue feel free to do so.