Format function flattens JSON

Terraform
1

Currently (0.13.5), the format(“format”,“inputs”) function flattens map outputs:

echo ‘format(“myout: %v”,{ b = “b”, a = “a” })’ | terraform console
myout: {“a”:“a”,“b”:“b”}

How can I get the output to be:

myout: {
"a":"a",
"b":"b"
}
2

Try tomap function tomap - Functions - Configuration Language - Terraform by HashiCorp

> tomap({"a" = 1, "b" = 2})
{
  "a" = 1
  "b" = 2
}
3

Hi @donald.bower,

I think in this particular case probably the best answer with today’s Terraform language would be to use the jsonencode function instead, which produces non-compact JSON:

jsonencode({ b = “b”, a = “a” }}

If you need that myout: prefix then you can use normal template interpolation to achieve that:

"myout: ${jsonencode({ b = “b”, a = “a” }}}"

If you’re using format because in your real example you’re using some other formatting features other than just concatenation of a prefix, you can still do that by using the %s verb to include the jsonencode result:

format("myout: %s", jsonencode({ b = “b”, a = “a” }))

I hope one of those options gives you a starting point for getting the result you need.

4

Returning to this a little later, I realize that I didn’t actually address what you asked about because I was distracted when I wrote this and was thinking about yamlencode rather than jsonencode.

jsonencode also generates the most compact form of JSON, so what I wrote here wouldn’t help you.

With that said, if you just output the JSON without any special prefix then Terraform’s value renderer has a special heuristic for that where it’ll show you the effective value of the JSON rather than the literal string, so if your aim is only to get a readable value for display then removing that myout: prefix might get you there with Terraform as it currently exists.