How to construct a string containing the keys of a map in Terraform?-CodePudding

I have a bunch of files that are published to an S3 bucket managed using the terraform script below. To make file tracking easy, I used a combination of for_each when declaring an aws_s3_object and fileset() to grab the list of files from my local volume.

I want to create an SSM Parameter that contains a common separated string of the list of files that I have published to S3 using the aws_s3_object (ie: "scripts/app/script1.py, scripts/app/script2.py, scripts/app/script3.py")

My approach to this problem is to use a combination of locals block and for statement to iterate over each key of aws_s3_object.app_files map and construct the string, but I can't figure out how to write this for statement as the examples from the documentation seem to suggest that the results of the for statement will result in a list or object and not a string.

Is it even possible to do this? And if so, how can this be achieved?

resource "aws_s3_object" "app_files" {
  for_each  = fileset("scripts/", "**.py")

  bucket = "myBucket"
  key = "dev/app/${each.value}"
  server_side_encryption = "aws:kms"
  bucket_key_enabled = true

  source = "scripts/${each.value}"
  source_hash = filemd5("scripts/${each.value}")

  tags = {
    Name = each.value
  }
}

CodePudding user response：

The easiest would be to use join:

locals {
  joined_keys = join(",", keys(aws_s3_object.app_files)) 
}

Sometimes, json string may be more useful:

locals {
  joined_keys_json = jsonencode(keys(aws_s3_object.app_files)) 
}