SaltStack: Use directory as source only if it exists - directory-structure

Question

I'd like to know if there's a way of running a SaltStack state only if a directory source is defined in the master.
Basically, I want to allow fo users to put certain configuration files in their HOME directory. Most of the users won't have anything special, but some of them might (a custom .vimrc, for instance)
What I'd like to do is execute a file.recurse for the user's HOMEdirectory only if that directory exists in master.
As of now, I have the following:
{% for username in pillar['users'] %}
{{ username }}:
user:
- present
- home: /home/{{ username }}
[ . . . ] # (yadda, yadda, yadda)
# ToDo: Is there a way of not running this AT ALL if the users's directory is
# not present?
/home/{{ username }}:
file.recurse:
- user: {{ username }}
- group: ubuntu
- source:
- salt://users/{{ username }}
- require:
- user: {{ username }}
{% endfor %}
What I want to do is what in the code appears as the ToDo: If there's a directory salt://users/{{ username }} in the salt tree (or in the salt master), then execute the file.recurse with that directory as the source for the file.recurse. Otherwise, just skip that state and use with whatever default content of $HOME is has when a user is created (just do nothing, I mean).
I thought adding an onlyif clause to the file.recurse configuration (something like - onlyif: test -e salt://users/{{ username }} would help... but nopes... I also tried to create an empty directory in salt://users/empty_dir/ and pass it as a default (as described here for a file.managed), but that trick doesn't work with file.recurse (at least not yet):
Thank you in advance.

Answer 1

You could try something similar to
{% for username in pillar['users'] %}
{{ username }}:
user:
- present
- home: /home/{{ username }}
[ . . . ] # (yadda, yadda, yadda)
# NB!!!! POTENTIAL PERF BOTTLENECK
{% if 'users/'+username not in salt['cp.list_master_dirs'](prefix='users') %}
/home/{{ username }}:
file.recurse:
- user: {{ username }}
- group: ubuntu
- source:
- salt://users/{{ username }}
- require:
- user: {{ username }}
{% endif %}
{% endfor %}