The current documented grains precedence is unusable in certain cases for custom grains

[edgan]

I want to set a grain in one state, reload_grains: True, do some stuff in the middle, and then change the same grain in another state. I use some jinja below to reload the grain, and set a variable in the state. But the rendering of the code before execution checks to see if the grain exists, doesn't find it, and throws an error.

So a grain set from within the state doesn't apply. I tried to initialize the grain with _grains, but with the current precedence, it always overrides my in state grains. The current precedence is inconsistent between core grains and custom grains.

Sane precedence:

_grains become before /etc/salt/grains instead of after

Documented precedence:

https://docs.saltstack.com/en/latest/topics/targeting/grains.html#precedence


Core grains.
Custom grains in /etc/salt/grains.
Custom grains in /etc/salt/minion.
Custom grain modules in _grains directory, synced to minions.

Error:

/var/cache/salt/minion/files/base/baseline/map.jinja(50):

---
[...]
    'mirror': 'mirror.foo.com'
  },
}
, grain="mirror", merge=salt['pillar.get']('baseline')) %}

{% do defaults.baseline.update(mirror_map) %}    <======================

{% set settings = salt['pillar.get']('baseline', default=defaults.baseline, merge=True) %}

---
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/salt/utils/templates.py", line 368, in render_jinja_tmpl
    output = template.render(**decoded_context)
  File "/usr/lib/python2.7/site-packages/jinja2/environment.py", line 969, in render
    return self.environment.handle_exception(exc_info, True)
  File "/usr/lib/python2.7/site-packages/jinja2/environment.py", line 742, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "<template>", line 1, in top-level template code
  File "/usr/lib/python2.7/site-packages/jinja2/environment.py", line 1013, in make_module
    return TemplateModule(self, self.new_context(vars, shared, locals))
  File "/usr/lib/python2.7/site-packages/jinja2/environment.py", line 1070, in __init__
    self._body_stream = list(template.root_render_func(context))
  File "/var/cache/salt/minion/files/base/baseline/map.jinja", line 50, in top-level template code
    {% do defaults.baseline.update(mirror_map) %}
TypeError: 'NoneType' object is not iterable

Jinja:

{% set mirror_map = salt['grains.filter_by']({
  False: {
    'mirror': 'mirror.example.com'
  },
  True: {
    'mirror': 'mirror.foo.com'
  },
}
, grain="mirror", merge=salt['pillar.get']('baseline')) %}

[jfindlay]

@edgan, thanks for the report. These other issues also discuss the precedence issue: #27005, #19611, #16268.

[skoenig]

Seems like due to restructuring the precedence of grains documentation has been moved from the 'targeting' page to https://docs.saltstack.com/en/latest/topics/grains/#precedence since this issue was opened. As @jfindlay mentioned, the documentation issue was also addressed in #27005 which was resolved then by #27706 - at least for the 2015.5 release.
I experienced in salt 2016.3.3 (Boron) that the last two instances in the precedence list are not correct:

3. Custom grains in /etc/salt/minion.
4. Custom grain modules in _grains directory, synced to minions.

File-based grains in /etc/salt/minion definitely override grain modules in the _grains module. So for me it seems the precedence section should be reverted to a067e6c. Should I open another issue or is this related enough?

[stale]

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