omit does not work in task environment

[pjnagel]

ISSUE TYPE

• Bug Report

COMPONENT NAME

task environment argument (all modules, not specific to a any module)

ANSIBLE VERSION

ansible 2.3.1.0
  config file = /home/pieter.nagel/setup/lautus_ansible/ansible.cfg
  configured module search path = Default w/o overrides
  python version = 3.5.2 (default, Nov 17 2016, 17:05:23) [GCC 5.4.0 20160609]

CONFIGURATION

Nothing relevant

OS / ENVIRONMENT

Ubuntu 16.04

SUMMARY

Using the 'some_var | default(omit)' construct in the context of environment values does not work as expected.

If this is not expected to work, the docs should be clearer on this topic, and this bug report should be considered a wishlist item that this construct should be made to work.

STEPS TO REPRODUCE

- shell: 'printenv | grep XYZZY'
  environment:
    XYZZY: '{{ undefined_variable | default(omit) }}'
  register: result

- debug: msg='{{ result.stdout }}'

EXPECTED RESULTS

I expected result.stdout to be entirely empty.

ACTUAL RESULTS

The environment variable was set:

TASK [tau_devel : debug] **********************************************************************************************************************************************************************************************************************************************************
ok: [dev3.lautus.net] => {
    "msg": "XYZZY=__omit_place_holder__3a9b44ab3747672df782fe3743c15e71a5db5202\nSUDO_COMMAND=/bin/sh -c echo BECOME-SUCCESS-rqhncxoovhhmrvncugmtexxjsqombzdm; XYZZY=__omit_place_holder__3a9b44ab3747672df782fe3743c15e71a5db5202 /usr/bin/python3.5"
}

[nitzmahone]

Yeah, omit is currently only implemented for module args ATM, but I could definitely see uses for it in other contexts as well...

[ansibot]

cc @dharmabumstead
click here for bot help

[ansibot]

cc @bkimble
click here for bot help

[pilou-]

Current documentation states: it is possible to use the default filter to omit module parameters using the special omit variable is that not clear enough ? if so, docs can be removed.

[s-hertel]

You can use something like

environment: '{{ env|default(omit, true) }}'
vars:
  maybe_env:
    FOO: "foo"
    BAR: '{{ some_variable | default(omit) }}'
  env: '{{ dict(maybe_env|dictsort|rejectattr("1", "eq", omit)) }}'

Or compressed:

environment: '{{ dict(env|dictsort|rejectattr("1", "eq", omit))|default(omit, true) }}'
vars:
  env:
    FOO: "foo"
    BAR: '{{ some_variable | default(omit) }}'

as a workaround

[s-hertel]

We discussed this in backlog today and don't plan on implementing the feature since there are workarounds. We may revisit in the future once data tagging is possible.