Ability to ignore changes to image_uri when function updates are performed outside of Terraform

[danielwhatmuff]

Is your request related to a new offering from AWS?

No

Is your request related to a problem? Please describe.

When managing docker/ECR based lambda deployments outside of Terraform (e.g. through CI/CD using the AWS CLI aws lambda update-function-code --image-uri ...) it would be good to have the ability to ignore image_uri.

This would enable consumers to continue making changes to function configuration and IAM policy etc using Terraform but continously deploy new image versions to the function via CI/CD.

Describe the solution you'd like.

Support a new boolean variable to ignore changes to image_uri e.g. ignore_image_uri. Similar to the ignore_source_code_hash variable used for ignoring changes to zip based functions. Due to the frustrating limitation of not being able to conditionally define lifecycle ignore_changes, this would likely need to be two lambda resource blocks - one with, one without the ignore.

Describe alternatives you've considered.

No known alternative, ignore_source_code_hash does not ignore changes to image_uri.

Additional context

A workflow I use to manage Lambda functions is to initially provision functions using Terraform with a placeholder image held in ECR and then setup CI/CD to iterate the docker image version. When changes to IAM policy or concurrency are made in Terraform there is unwanted drift detected with image_uri.

[StanDeeks]

Would also love this.