convert map to list for terraform aws_autoscaling_group

user_5442187 0
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I have the following map of subnet ids as a variable to be used in a Terraform aws_autoscaling_group resource:

subnet_ids = {
  "us-east-1" = "subnet-123abc,subnet-456def,subnet-789ghi"
  "us-west-2" = "subnet-1a2b3c,subnet-4c5d6e,subnet-7g8h9i"
}

and variable as 

variable subnet_ids {
  description = "subnet ids"
  type        = "map"
}

but this not working as Terraform is complaining that it needs a list but is seeing a map.

This worked by just setting up one region temporarily:

subnet_ids = ["subnet-123abc", "subnet-456def", "subnet-789ghi"]

and variable as:

variable subnet_ids {
  description = "subnet ids"
  type        = "list"
}

and passed as vpc_zone_identifier = "${var.subnet_ids}"

So pretty much want a way to be able to use the map and be able to pass in lists based on the region picked

Thanks

terraform-provider-aws terraform amazon-web-services
3 Answers

Try using the lookup command and a variable to represent your region to choose a value from your map:

variable region {
   description = "aws region"
   default = "us-east-1"
}

...

vpc_zone_identifier = ["${lookup(var.subnet_ids, var.region)}"]

See the documentation for more examples.

user_8660210

For anyone facing issues with security groups for autoscaling group resource in terraform, this is how you pass map to list

this is what worked

security_groups = ["${split(",",lookup(var.security_groups, var.aws_region))}"]
user_54421870

Or...

variable region {
   description = "aws region"
   default = "us-east-1"
}

...

vpc_zone_identifier = ["${var.subnet_ids["${var.region}"]}"]
user_15068580
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