aws_lambda_alias not updating on new aws_lambda_function version

[niklaskhf]

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Terraform Version

Terraform: v0.12.24
provider.aws: v2.59.0

Affected Resource(s)

• aws_lambda_function
• aws_lambda_alias

Terraform Configuration Files

resource "aws_lambda_function" "example" {
  function_name = "example-lambda"
  handler = "main"
  role = aws_iam_role.lambda_role.arn
  runtime = "go1.x"
  filename = "../code.zip"
  timeout = 20
  memory_size = 128
  reserved_concurrent_executions = 1
  publish = true
}

resource "aws_lambda_alias" "example" {
  name             = "example-alias"
  description      = "latest version"
  function_name    = aws_lambda_function.example.arn
  function_version = aws_lambda_function.example.version

  depends_on=[aws_lambda_function.example]
}

Debug Output

Panic Output

Expected Behavior

The aws_lambda_funcion resource gets updated to a new version, because publish=true. The aws_lambda_alias resource gets updated to the new version of aws_lambda_function.

Actual Behavior

The aws_lambda_funcion resource gets updated to a new version, because publish=true. The aws_lambda_alias does not get updated until the next apply.

Steps to Reproduce

1. terraform apply -> aws_lambda_function gets updated
2. terraform apply -> aws_lambda_alias gets updated

Important Factoids

References

• resource/aws_lambda_function: Recompute Lambda function version and qualified_arn on publish #3032
• Using aws_eip without aws_eip_association is "bad" #628
• Handling of aws_lambda_alias on aws_lambda_function publish true #3192

[yaochaoutokyo]

Exactly the same problem here. I tried to use a lambda alias named "prod" to point to the latest published version. However, when I modify the lambda function configuration and set the publish=true, the function gets a new version, but the alias doesn't get updated to the new version.

[jbilliau5668]

Yup, same here!

[andrewwheal]

This seems to be a regression of #2915

[kevinmstephens]

I think I may have found the reason. I opened this ticket with my best guess at the cause. #14210.

Copied here:

Guess at Cause

I believe I have found the cause but I'd hope someone can confirm.

It seems that the auto-publish feature is used in updating lambdas. This API call to AWS will return the updated version. However the AWS provider doesn't appear to use that version and instead appears to call get-function-versions and grab the largest version from the return list and use that value. However, I've confirmed with AWS Support that get-function-versions isn't a strongly consistent call and in fact is eventually consistent and has a cache TTL (length unknown).

I believe that the calls to get-function-versions sometimes returns stale data and so the new version is not present.

To solve this issue the AWS provider should use the version returned from the update-function call (create-function call too if that's relevant).

[ghost]

This has been released in version 3.29.0 of the Terraform AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template for triage. Thanks!

[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!