feat(jinja): add macros.jinja file to accumulate common macros

[noelmcloughlin]

This PR introduces a 1st revision of a common jinja/macros.j2 file to gather generic macros. The first revision includes a format_kwargs macro.

Background:
The format_kwargs macro is generic solution used in two formulas-

• ceph-formula
• postgres-formula

format_kwargs macro
This macro makes short work of rendering SLS lists which must be generated by mapping files and the switching of grains.

Use Case

osfamilymap.yaml

Debian:
  pkg:
    repo:
      name: 'deb https://packages.template.org/debian stable main'
      key_url: https://packages.template.org/debian/template.org.key
      file: file: /etc/apt/sources.list.d/template.list
      dist: stable

RedHat:
  pkg:
    repo:
      name: template-cli
      baseurl: https://packages.template.org/redhat
      key_url: https://packages.template.org/redhat/template.org.key
      enabledTrue: 1

package/install.sls

{%- from tplroot ~ "/jinja/macros.j2" import format_kwargs with context -%}

template-package-repo-managed:
  pkgrepo.managed:
    {{- format_kwargs(template.pkg.repo) }}
    - require_in:
      - pkg: template-package-install-pkg-installed

[myii]

Just the doubled Jinja whitespace control, due to the linked comment.

[myii]

Thanks for this, @noelmcloughlin. I think the idea itself is sound but we all need discuss how to proceed, with respect to consistency and a number of ongoing discussions:

1. Using a jinja sub-directory; we haven't done so far, such as with libtofs.jinja but it's probably a good idea to separate these libraries somewhere.
2. Using the .j2 file extension; we're primarily using .jinja so far; when's the right time to use .j2 and the right time to use .jinja? Is it worth using one for libraries and the other for templates?
3. Should we group numerous macros under macros.xyz or should we have separate libraries for each one, with consideration to spreading updates across numerous formulas?
4. How should we implement this with regards to [Discussion] [Idea] Move all utilities for formulas outside of edited files (states, yaml) #122?
5. Any decisions here will also affect chore(libsaltcli): add lib to check type of Salt command being used #131.

If we're going to follow our current implementation scheme, then this should be something like:

{%- from tplroot ~ "/libkwarg.jinja" import format_kwargs with context %}

However, I am not proposing that we continue with this scheme.

[noelmcloughlin]

Hi @myii

Using a jinja sub-directory; we haven't done so far, such as with libtofs.jinja but it's probably a good idea to separate these libraries somewhere.

macros are an advanced feature of a rendering language. It is probably a sound principle to hide the implementation since they are secondary libraries designed to cleanup overuse of jinja in SLS files.

when's the right time to use .j2 and the right time to use .jinja? Is it worth using one for libraries and the other for templates?

Fixed. Let's stick with jinja because the version is just an implementation detail.

Should we group numerous macros under macros.xyz or should we have separate libraries for each one, with consideration to spreading updates across numerous formulas?

There is no right answer. It's unclear if loading a single macro from a common library file incurs increased performance, compared to a modular library implementation. Buts It's a more simple implementation. We could start here and evolve.

This can wait until #122 and #131 become clearer.

[noelmcloughlin]

Here is another macro from prometheus-formula (only) which maybe portable too.

{#- Contactenate arguments #}
{%- macro concat_args(args) %}
{%-   set args = args|dictsort %}
{%-   if args|length > 0 %}
{%-     for k,v in args -%}
{%-       if not k or not v %}{% continue %}{% endif -%}
          --{{ k }}={{ v }}
{%-       if not loop.last %} {% endif -%}
{%-     endfor -%}
{%-   endif -%}
{%- endmacro %}

Anyway wait until #122 and #131 become clearer.

[noelmcloughlin]

I'll close this as duplicate or #122

[pull-assistant]

Best reviewed: commit by commit

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     feat(jinja): add macros.j2 file to accumulate common macros

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