Unable to use user variable in vagrantfile_template with HCL2 packerfile

[aacebedo]

Overview of the Issue

I am generating a vagrantfile when creating a box with packer. In this vagrantfile, I use variables defined in the packer file.
In the vagrantfile.tpl I add tags like {{ user myvariable }}. When I use a JSON packer file, everything is ok.
I upgraded my packer json file into the HCL2 format and the syntax seems to have changed for those variables as they are not replaced anymore. I may be missing something here but the document "engine" page of the JSON section does not exist in the HCL section.

Reproduction Steps

• Create a HCL2 packer file using the vagrant post-processor
• In the vagrant post-processor define a vagranfile_template file
• In the vagrantfile template refers to user defined variables coming from the packer file using the {{ user myvariable }} syntax.
• Run packer build, the variables are not changed.

Packer version

1.7.0

Simplified Packer Buildfile

file.pkr.hcl
[...]
  locals {
   mylocal = "helloworld"
  }
  post-processor "vagrant" {
    keep_input_artifact = true
    vagrantfile_template = ./vagrantfile.tpl
  }
[...]

file vagrantfile.tpl
[...]
something = {{ user `mylocal` }}
[...]

Operating system and Environment details

Linux x86_64

Log Fragments and crash.log files

N/A

[aacebedo]

I have investigate a little bit.
It appears that putting {{ user "VariableName" }} shall be the way to get the values.
However even if I put a local or a variable in the HCL file, the ctx.UserVariables is not empty when the post-processor is called.
This leads to enter the line funcs.go:222 located in packer-plugin-sdk/template/interpolate where the code is:

		if ctx == nil || ctx.UserVariables == nil {
			return "", errors.New("test")
		}

So when the UserVariables variable is empty I got a weird error containing "test" and it fails the build with:

* Post-processor failed: template: root:4:2: executing "root" at <user `.Toto`>: error calling user: test

I am still searching why the UserVariables is empty when the post processor is called

[SwampDragons]

The vagrantfile isn't a full template, and the only variables that can currently be used in it are {{ .BoxName }} and {{ .SyncedFolder }}

https://www.packer.io/docs/builders/vagrant#template

[aacebedo]

Unfortunately it is the case in the json version and it is a feature I heavily relies on. Thus I won't be able to migrate to hcl2 :(
The code gives the impression that it is a feature that will be added (i.e. the "test" error). Do you think it will be placed on the roadmap or juste considered as nice to have and implemented on a best effort basis ?

[aacebedo]

The vagrantfile isn't a full template, and the only variables that can currently be used in it are {{ .BoxName }} and {{ .SyncedFolder }}

https://www.packer.io/docs/builders/vagrant#template

Note that the link is pointing to the builder. The issue I saw is on the post-processor and its documentation mentions user variables (https://www.packer.io/docs/post-processors/vagrant#output).

[ghost]

This issue has been automatically migrated to hashicorp/packer-plugin-vagrant#9 because it looks like an issue with that plugin. If you believe this is not an issue with the plugin, please reply to hashicorp/packer-plugin-vagrant#9.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.