ValueError: Fn::Sub not allowed to be nested in None

[anatanna]

Template: https://aws-ia-us-east-1.s3.us-east-1.amazonaws.com/cfn-ps-darktrace-vsensor/templates/darktrace-vsensor-workload.template.yaml

Environment:
Python 3.11.5 pip 23.3.1 from /home/user/venv_3.11/lib64/python3.11/site-packages/pip (python 3.11) cf2tf 0.6.2

Error: // Converting darktrace-vsensor-workload.template.yaml to Terraform! Traceback (most recent call last): File "/home/localadmin/venv_3.11/bin/cf2tf", line 8, in sys.exit(cli()) ^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/click/core.py", line 1157, in call return self.main(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/click/core.py", line 1078, in main rv = self.invoke(ctx) ^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/click/core.py", line 1434, in invoke return ctx.invoke(self.callback, **ctx.params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/click/core.py", line 783, in invoke return __callback(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/app.py", line 44, in cli config = TemplateConverter(tmpl_path.stem, cf_template, search_manger).convert() ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 97, in convert tf_resources = self.convert_to_tf(self.manifest) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 144, in convert_to_tf tf_resources.extend(converter(resources)) ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 344, in convert_resources resolved_values = self.resolve_values( ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 176, in resolve_values data[key] = self.resolve_values( ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 176, in resolve_values data[key] = self.resolve_values( ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 206, in resolve_values value = self.resolve_values( ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 206, in resolve_values value = self.resolve_values( ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 217, in resolve_values resolved_list_values = [ ^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 218, in self.resolve_values(item, allowed_func, prev_func) for item in data ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 176, in resolve_values data[key] = self.resolve_values( ^^^^^^^^^^^^^^^^^^^^ File "/home/localadmin/venv_3.11/lib64/python3.11/site-packages/cf2tf/convert.py", line 204, in resolve_values raise ValueError(f"{key} not allowed to be nested in {prev_func}.") ValueError: Fn::Sub not allowed to be nested in None.

[shadycuz]

oh this is an interesting bug, thanks for reporting.

[shadycuz]

This indeed turned out to be interesting and tricky to fix.

The issue is that Cloudformation allows two forms of it's "Sub" function. There is the single version: !Sub some-${var} and then the list form:

!Sub:
 - some-${var}
 - var : foo

The issue is that I don't think !Sub some${!Sub ${var}} is valid, but this is:

!Sub:
 - some-${var}
 - var: !Sub "${var}"

I don't currently have an easy way to fix this, but its on my radar.