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0) display the config_context:

   top level context item:

   {{ config_context }}

   selecting the best unicorn with config_context['best_unicorn'][0]:

   {{ config_context['best_unicorn'][0] }}

   accessing a key pair injected into the jinja environment global variables:
   (in this case the config_context printed out in human readable yaml format)

   {% filter indent(width=3) %}
   {{ pretty_config_context }}
   {% endfilter %}

   loop through the config_context variable in jinja:

   {% for key, value in config_context.items() %}
   {{ key }}:{{ value }}
   {% endfor %}

1) source template ./device/{{ config_context['device'] }}.yml

2) source template ./device/region/{{ config_context['region'] }}.yml

3) source template ./device/site/{{ config_context['site'] }}.yml

4) source template ./device/role/<files>.yml
   these contexts happens to be a list in the inventory
   files under this directory happen to have the same weight(they dont have to)
   thus these files do not have the same keys as they would clash

   {% if config_context['gabbys_doll_house'] %}
   gabbys_doll_house = {{ config_context['gabbys_doll_house'] }}
   {% endif %}

   {% if config_context['octonaughts'] %}
   octonaughts = {{ config_context['octonaughts'] }}
   {% endif %}

   notice best_unicorn is in the all.yml context and router.yml context
   router.yml has a higher precedence(lower weight value)

   {% if config_context['best_unicorn'] %}
   {% for entry in config_context['best_unicorn'] %}
   - {{ entry }}
   {% endfor %}
   {% endif %}

   {% if config_context['harry_potter'] %}
   harry_potter = {{ config_context['harry_potter'] }}
   {% endif %}
   
   notice cbeebies_schedule is in the all.yml context and vpn.yml context
   all.yml context is weighted last/-1, any other context will overwrite it
   vpn.yml has a higher precedence(lower weight value)

   {% if config_context['cbeebies_schedule'] %}
   cbeebies_schedule = {{ config_context['cbeebies_schedule'] }}
   {% endif %}

4) source template ./device/role/all.yml
   nothing is rendered using this context, all variables are overwritten by contexts with higher precedence
   this would be a good place to put service accounts in ACLs or legal disclaimers

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