How to get an arbitrary remote user’s home directory in Ansible?

Ansible (from 1.4 onwards) already reveals environment variables for the user under the ansible_env variable.

- hosts: all
  tasks:
    - name: debug through ansible.env
      debug: var=ansible_env.HOME

Unfortunately you can apparently only use this to get environment variables for the connected user as this playbook and output shows:

- hosts: all
  tasks:
    - name: debug specified user's home dir through ansible.env
      debug: var=ansible_env.HOME
      become: true
      become_user: "{{ user }}"

    - name: debug specified user's home dir through lookup on env
      debug: var=lookup('env','HOME')
      become: true
      become_user: "{{ user }}"

OUTPUT:

vagrant@Test-01:~$ ansible-playbook -i "inventory/vagrant" env_vars.yml -e "user=testuser"

PLAY [all] ********************************************************************

GATHERING FACTS ***************************************************************
ok: [192.168.0.30]

TASK: [debug specified user's home dir through ansible.env] *******************
ok: [192.168.0.30] => {
    "var": {
        "/home/vagrant": "/home/vagrant"
    }
}

TASK: [debug specified user's home dir through lookup on env] *****************
ok: [192.168.0.30] => {
    "var": {
        "/home/vagrant": "/home/vagrant"
    }
}

PLAY RECAP ********************************************************************
192.168.0.30               : ok=3    changed=0    unreachable=0    failed=0

As with anything in Ansible, if you can’t get a module to give you what you want then you are always free to shell out (although this should be used sparingly as it may be fragile and will be less descriptive) using something like this:

- hosts: all
  tasks:
    - name: get user home directory
      shell: >
             getent passwd {{ user }}  | awk -F: '{ print $6 }'
      changed_when: false
      register: user_home

    - name: debug output
      debug:
        var: user_home.stdout

There may well be a cleaner way of doing this and I’m a little surprised that using become_user to switch to the user specified doesn’t seem to affect the env lookup but this should give you what you want.