Set an env var for only the provisioner

Question

I need an environment variable added to the front of $PATH that:

1. Doesn't last beyond the provisioning run.
2. Is dependent i.e. something will be installed earlier in the run that is then is available via $PATH, so I can't set it globally as this cookbook says to.

I tried the answer here:

Exec { environment => [ "foo=$bar" ] }

but I get the error Error: All resource specifications require names. When I add a name I get other errors about syntax, for which my fiddling around to fix just gives me other errors (the error Syntax error at '}'; expected '}' is my favourite!)

I've tried using export to set it, but I see: Error: Could not find command 'export'

I've tried using set and setenv too, with similar results. There must be a straightforward way to do this, but I can't find it.

Edit

Just to add, these are the available shells:

$ cat /etc/shells
# /etc/shells: valid login shells
/bin/sh
/bin/dash
/bin/bash
/bin/rbash
/bin/zsh
/usr/bin/zsh

zsh is part of the provisioning, but it could be a requirement of the answer, if needs be.

Answer 1

I tried a few ways for this, but the best I found was to use Hiera. I read quite a few blogs on how to set this up with Vagrant too, but this was the best I found.

My project directory layout

Vagrantfile
pp/
  manifests/
  modules/
  data/
    hiera.yml
    common.yml

Vagrantfile

The relevant part of the Vagrantfile:

  config.vm.provision "puppet" do |puppet|
    puppet.manifests_path = "pp/manifests"
    puppet.module_path = "pp/modules/custom"
    puppet.manifest_file  = "default.pp"
    puppet.hiera_config_path = "pp/data/hiera.yaml"
  end

I've no idea yet why there needs to be a hiera.yaml which points to a common.yaml, but that's the way it is.

hiera.yaml

---
:backends:
  - yaml

:hierarchy:
  - "common"

:yaml:
  :datadir: '/vagrant/pp/data'

common.yaml

---
ruby_version: "2.3.0"
ruby_prefix: "/opt/rubies"
...

Then in a manifest

$ruby_version = hiera("ruby_version")
$ruby_prefix = hiera("ruby_prefix")
$ruby_dir_fullpath = "${ruby_prefix}/ruby-${ruby_version}"

Seems like a lot of effort to me, but again, that's the way it is.