exclude{...} block does not work in terragrunt.stack.hcl files

[devourer66]

Describe the bug

exclude{...} block does not work in terragrunt.stack.hcl files

Steps To Reproduce

Add the exclude{} block to terragrunt.stack.hcl

exclude { # former skip=true|false
  if = true # Boolean to determine exclusion.
  no_run=true # Boolean to prevent the unit from running (even when not using `--all`).
  actions = [ # List of actions to exclude (e.g., "plan", "apply", "all", "all_except_output").
    "all",
    # "all_except_output",
    # "plan",
    # "apply",
    # "destroy",
    ]
}

and run

$ terragrunt --version
terragrunt version v0.93.10

$ terragrunt plan --all
21:20:53.874 ERROR  Error: Unsupported block type
21:20:53.875 ERROR    on ./pathtostack/terragrunt.stack.hcl line 7, in exclude:
21:20:53.875 ERROR     7: exclude { # former skip=true|false
21:20:53.875 ERROR  Blocks of type "exclude" are not expected here.
21:20:53.876 ERROR  failed to generate stack file: error occurred:

* Failed to read stack file ./pathtostack/terragrunt.stack.hcl in ./evenlongerpath/pathtostack/terragrunt.stack.hcl:7,1-8: Unsupported block type; Blocks of type "exclude" are not expected here.

21:20:53.879 ERROR  Unable to determine underlying exit code, so Terragrunt will exit with error code 1

NOTE: skip=true also was not working before it was deprecated

Expected behavior

It is expected that users are able to exclude stack processing from the queue.

Additional context

There are cases when a stack is used as a generator for units:

./_unit_tpl_many_of_these/terragrunt.hcl

include "root" {
  path   = find_in_parent_folders("root.hcl")
  expose = true
}

locals {
  base_source = "${dirname(find_in_parent_folders("root.hcl"))}/..//modules"
}

terraform {
  source = "${local.base_source}/some_module"
}

# In this unit template, the queue control is used to exclude the template from processing
prevent_destroy = true
exclude {
  if = try(!fileexists(".terragrunt-stack-manifest"), true)
  actions = ["all"]
  no_run               = true  
  exclude_dependencies = false 
}

inputs = try(read_terragrunt_config("terragrunt.values.hcl"), {})

./terragrunt.stack.hcl

locals {
  # variables shared across units
   some_var= "something"
}

unit "first_of_many" {
  source                  = "./_unit_tpl_many_of_these"
  path                    = "first_of_many"
  no_dot_terragrunt_stack = true  

  values = merge(
    local,
    # overrides and extensions
    {
        some_var= "other_something"
    }
  )
}

[denis256]

Hello,
for now, exclude block works only in terragrunt.hcl files, "run queue" is created only for terragrunt.hcl files.

https://terragrunt.gruntwork.io/docs/features/runtime-control/#exclusion-from-the-run-queue

[devourer66]

Hello, for now, exclude block works only in terragrunt.hcl files, "run queue" is created only for terragrunt.hcl files.

https://terragrunt.gruntwork.io/docs/features/runtime-control/#exclusion-from-the-run-queue

Do you see any possible alternatives or workarounds to achieve the exclusion of the stack from the queue without using command flags?

[project0]

how about passing through a variable from the stack declaration and use it in the actual unit? However, i believe #4504 will solve it eventually. But i agree the discrepancy between terragrunt.stack.hcl and terragrunt.hcl of functions/blocks supports is kinda confusing and frustrating (especially as its not really documented).

something like this might work as workaround:
terragrunt.stack.hcl :

unit "first_of_many" {
  source                  = "./_unit_tpl_many_of_these"
  path                    = "first_of_many"
  no_dot_terragrunt_stack = true  

  values = {
      is_stack = true
   }
}

terragrunt.hcl :

locals {
  values  = read_terragrunt_config("${get_terragrunt_dir()}/terragrunt.values.hcl")
}
exclude {
  if = try(!local.values.is_stack, true)
  actions = ["all"]
  no_run               = true  
  exclude_dependencies = false 
}

[yhakbar]

Closing this issue out, as it's not a bug.