Remove indentfirst in system-probe.yaml.j2

[tasktop-teho]

What does this PR do?

Removes specification of the obsolete indent filter argument identfirst.
Fixes #360

Motivation

The indentfirst option no longer supported in jinja 3

[bkabrda]

Thanks for submitting this PR! The problem is that using first would break older installations that have Jinja2 < 2.10. I think we could work around this by not using first at all and adding an extra empty line that would be considered the first unindented line (which would make all of the actual lines indented):

system_probe_config:
{% filter indent(width=2) %}

{{ system_probe_config | to_nice_yaml }}
{% endfilter %}

This would result in the first line being blank and unindented, and all of the lines of the system_probe_config would be indented by 2 spaces correctly. The unindented blank line doesn't break yaml parsing, so everything should, in theory, work ok. I'll need to test this approach carefully to ensure it works as expected.

[tasktop-teho]

@bkabrda That's a nice approach. What about not specifying the keyword first or indentfirst, and let positional argument takes care of it?
{% filter indent(width=2, True) %}

[bkabrda]

@tasktop-teho you're right that this also possible (and probably even better), but for it to work you'd need to modify the call to be indent(2, True), because you can't use keyword argument before a non-keyword argument. Doing so would lead to an error like this: jinja2.exceptions.TemplateSyntaxError: invalid syntax for function call expression. It would also be awesome if you could include a comment above these calls that would explain that we have to keep using non-keyword args because of backwards compatibility. Thanks!

[bkabrda]

Looks good now, merging. Thank you for the contribution!

[tasktop-teho]

Thank you for the constructive advice

[hoshsadiq]

@bkabrda any ideas when there will be a new release with this change? We're running into the same issue.

[basil]

Would it be possible to cut a release with this change?

[bkabrda]

Sure, I'll do the pre-release tests today and cut a new release if everything checks out - hopefully today/tomorrow, if I find no issues.

[bkabrda]

I've just released 4.10.0 version of the Datadog role. See https://github.com/DataDog/ansible-datadog/releases/tag/4.10.0 for changelog. It's now also available on Ansible Galaxy: https://galaxy.ansible.com/DataDog/datadog