Add scope parameter to systemd

[hi117]

SUMMARY

This change changes the user: paramater into a state: paramater with the following choices:

• system
• user
• global

with system being the default. The system scope is the default scope. The user scope matches with the old user: paramater. The global scope applies to all users.

An example use case would be masking a unit. In the system scope it would create the mask via symlink from /etc/systemd/system/. In the user scope it would mask via symlink from ~/.config/systemd/user/. In the global scope it would mask via symlink from /etc/systemd/user/.

Previously a global: paramater was tested but since global is a keyword in python, it caused errors during testing. Since this patch removes the old user: paramater, it is a backwards incompatible change.

Fixes #38828

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

systemd

ANSIBLE VERSION

ansible 2.5.0
  config file = /home/hi117/.ansible.cfg
  configured module search path = [u'/home/hi117/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.15 (default, May  1 2018, 20:16:04) [GCC 7.3.1 20180406]

ADDITIONAL INFORMATION

Output of make tests-nonet, snipped to only the relavent tests.

test/units/modules/system/test_systemd.py::ParseSystemctlShowTestCase::test_multiline_exec PASSED
test/units/modules/system/test_systemd.py::ParseSystemctlShowTestCase::test_simple PASSED
test/units/modules/system/test_systemd.py::ParseSystemctlShowTestCase::test_single_line_with_brace PASSED 

[ansibot]

The test ansible-test sanity --test validate-modules [explain] failed with 1 error:

lib/ansible/modules/system/systemd.py:0:0: E309 version_added for new option (scope) should be 2.6. Currently 0.0

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[maxamillion]

Hello and thank you for the pull request!

I'm a little concerned that this breaks backwards compatibility and it could have unexpected implications for users. Is there any approach to this that you can think of which would keep backwards compatibility and offer the fix?

[bcoca]

I'm fine with adding scope, but user should be deprecated, not removed and the interaction between both handled, with scope having precedence when set.

[hi117]

I didn't see in the documentation, but is there a standard way of makring something as deprecated?

[bcoca]

just add a note about deprecation in the description (and point to scope) and call module.deprecate() if it is set, our normal deprecation cycle is 4 versions, so if this goes in now (2.7) it should be removed in (2.11 or equivalent)

[opoplawski]

@hi117 just ran into this need. Any progress here?

[ansibot]

The test ansible-test sanity --test validate-modules [explain] failed with 1 error:

lib/ansible/modules/system/systemd.py:0:0: E309 version_added for new option (scope) should be 2.7. Currently 2.6

click here for bot help

[hi117]

I made the changes you suggested @bcoca, let me know if any other changes are needed.