Output of "terraform output -json"

Terraform
1

Hi,

I have the need of postprocessing the output of terraform output --json. While running that I noticed that it is “noisier” than expected.
I’m only interested in the value of the value key which would be more aligned with a json like .tf.json. Wouldn’t that be an option terraform could provide out-of-the box?
I’ll look into filtering it with jq for now.

2

The two valid methods I know of are below… maybe using bith could target just the item you want for less output clutter…

‘terraform output instance public ip’

List a specific declared output

‘terraform output -json’

List all outputs in JSON format

3

As I mentioned output ofterraform output -json is a bit noisy with a lot of extra stuff and also output values are in the value key instead of being the “.value” of the output variable key.

4

There are no plans to change the format of terraform output -json, as we consider it stable. The additional information is important for some users, and easily filtered using jq, which is our recommended approach:

$ terraform output -json
{
  "animal": {
    "sensitive": true,
    "type": "string",
    "value": "horse"
  }
}
$ terraform output -json | jq -r .animal.value
horse

Adding an extra flag to re-implement this simple jq filter is not something we’re likely to do.

1 Like
5

I understand that more details might be valuable in different cases. I still need valid json output but not just the value itself.
So this `jq provides the solution:

jq 'with_entries(.value |= .value)'

Output

{"animal": "horse"}

it also handles different types.

3 Likes
6

I find this frustrating as I can have outputs that are entire modules. And I can get the output JSON formatted by doing

terraform output -json name_of_module_output

But there is no way to get the output of the main module in a similar format. It would be nice if we could specify something like:

terraform output -json .

To be explicit, I’m suggesting that using a placeholder such as “.” for name would refer to the root modules, but perform the same as the command when called with a NAME parameter.

7

For anyone else stumbling across this from Google, the below will generate the requested json:

terraform output -json | jq '[to_entries | .[] | {(.key): .value.value}] | add'