Are there any methods to arrange order of variables evaluation on locals block

[Arpo201]

I want to generate a new file, then read it.

• Have cache (terragrunt init): Sometime it pass, sometime it fail.
• No cache (terragrunt init): it always pass, because it download terraform module and script is run finished before evaluation.
• before_hook: it always fail, and it is not actually before.

tg_render = run_cmd("tg-render.bash")
tg_config = jsondecode(file(local.tg_render_path)) # run_cmd("cat", "${local.tg_render_path}") is not work too

Fail

10:58:32.377 DEBUG  Evaluated 2 locals (remaining 8): env_vars, tg_render_path
10:58:32.378 ERROR  Error: Invalid function argument
10:58:32.378 ERROR    on ../../../../../../_templates/resources/aws/s3/s3-common.hcl line 19, in locals:
10:58:32.378 ERROR    19:   tg_config      = jsondecode(file(local.tg_render_path))

Pass

11:01:12.222 DEBUG  Evaluated 2 locals (remaining 8): tg_render_path, env_vars
11:01:12.223 DEBUG  run_cmd, cached output: [../../../../../../../../..
11:01:12.223 DEBUG  Evaluated 5 locals (remaining 3): tg_config, tg_render, kms_key_arn, bucket_name, aws_admin_roles

So, are there any methods to arrange order of variables evaluation ?

[yhakbar]

Hey @Arpo201 , why are you trying to create the file then read it? You can simply return the JSON payload as stdout from tg-render.bash.

HCL functions are evaluated concurrently in order to maximize performance, so unless there's a dependency between the locals, they'll be evaluated at the same time.

[Arpo201]

Thank you for your advice @yhakbar. Now, I'm using stdout from tg-render.bash, It works. Anyway, I also want to show logs on terminal for see information or troubleshooting if have some errors (Some part of tg-render.bash throw logs. I don't want to including these logs to local.variable).

[yhakbar]

You can log those messages to stderr, and they won't be returned to the local.

[Arpo201]

Wow, that works!! Thank you.

For anyone, this is my solution (File descriptors):

# tg-render.bash
terragrunt render-json > result.json
# Any subsequent commands that have stdout should use "1>&2"
echo "xxxx" 1>&2
cat "result.json"

# terragrunt.hcl
tg_render = run_cmd("tg-render.bash")

Explanation:
0 refers to standard input (stdin).
1 refers to standard output (stdout).
2 refers to standard error (stderr).