[Bug]: source_code_hash not getting persisted to tf statefile - causes lambda deployment even if there is no change in etag

[iammukeshm]

Terraform Core Version

1.3.9

AWS Provider Version

4.58.0

Affected Resource(s)

aws_lambda_function

Expected Behavior

Based on source_code_hash, lambda should not be re-deployed / changed if there is no difference in the etag or source_code_hash.

Actual Behavior

The source_code_hash isnt getting stored to the statefile for some reason. Because of this everytime I run a terraform plan or apply, the lambda gets re-deployed even if there is no new zip upload my s3 bucket.

Ran terraform apply 1st time.

Terraform will perform the following actions:

  # module.catalog_lambda.aws_lambda_function.lambda will be updated in-place
  ~ resource "aws_lambda_function" "lambda" {
        id                             = "catalog-lambda"
      ~ last_modified                  = "2023-03-11T04:53:26.000+0000" -> (known after apply)
      ~ source_code_hash               = "Wy8Y63xIwbF/VPCbNo3m374Sec6xepIwxqr1wdpAZ+Y=" -> "66121cb6a3e928951f671916547d622f"   
        tags                           = {}
        # (21 unchanged attributes hidden)

        # (3 unchanged blocks hidden)
    }

Ran terraform apply second time

Terraform will perform the following actions:

  # module.catalog_lambda.aws_lambda_function.lambda will be updated in-place
  ~ resource "aws_lambda_function" "lambda" {
        id                             = "catalog-lambda"
      ~ last_modified                  = "2023-03-11T04:53:46.000+0000" -> (known after apply)
      ~ source_code_hash               = "Wy8Y63xIwbF/VPCbNo3m374Sec6xepIwxqr1wdpAZ+Y=" -> "66121cb6a3e928951f671916547d622f"   
        tags                           = {}
        # (21 unchanged attributes hidden)

        # (3 unchanged blocks hidden)
    }

You can see that the source_code_hash is not getting persisted to the tf statefile.

Relevant Error/Panic Output Snippet

No response

Terraform Configuration Files

N/A

Steps to Reproduce

resource "aws_lambda_function" "lambda" {
  s3_bucket        = data.aws_s3_object.package.bucket
  s3_key           = data.aws_s3_object.package.key
  source_code_hash = data.aws_s3_object.package.etag
  function_name    = var.function_name
  role             = aws_iam_role.lambda_role.arn
  handler          = var.function_handler
  runtime          = var.runtime
  timeout          = var.timeout_in_seconds
  depends_on = [
    aws_iam_role_policy_attachment.lambda_policy_attachment,
    aws_iam_role.lambda_role,
    data.aws_s3_object.package
  ]

  environment {
    variables = {
      ASPNETCORE_ENVIRONMENT = "Development"
    }
  }
}

data "aws_s3_object" "package" {
  bucket = var.s3_bucket_name
  key    = var.s3_key
}

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

No response

Would you like to implement a fix?

None

[github-actions]

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[justinretzolk]

Related: #7385
Related: #17884
Related: #25647

Potentially related: #30029

[github-actions]

This functionality has been released in v5.32.0 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. Thank you!

[SalmaanPV]

I think the issue still persists, i have used the latest provider version 5.32.0. Still it's the same issue.Terraform re-plan or re-appy is causing the hash values change.
Expected output: No infra change
Actual output: hash value update
Why it's trying to update the source code hash?

Below is my source code:

Check if the object (zip file) exists in the S3 bucket

data "aws_s3_object" "lambda_zip" {
bucket = var.bucket_name
key = "${var.team_name}/${var.project_name}/${var.zip_file_name}.zip"
}

Create or update Lambda function based on the existence of the Lambda package in S3

resource "aws_lambda_function" "lambda_function" {
function_name = var.function_name
handler = var.handler
runtime = var.runtime
s3_bucket = var.bucket_name
s3_key = "${var.team_name}/${var.project_name}/${var.zip_file_name}.zip"
role = aws_iam_role.custom_lambda_execution_role.arn
timeout = 30
tags = var.tags

Configure Lambda to use VPC

vpc_config {
subnet_ids = var.vpc_subnet_ids
security_group_ids = var.vpc_security_group_ids
}

environment {
variables = var.environment_variables
}

Trigger an update only if the S3 object (zip file) content changes or Lambda doesn't exist

source_code_hash = data.aws_s3_object.lambda_zip != null ? data.aws_s3_object.lambda_zip.etag : null
}

Can someone help me out?

[github-actions]

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 have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.