feat: Inventory for variable values

This CL adds an experimental inventory area in the pillar data, which is
not return in the result and can easily access with a minion lookup
scope. It can be used for minion-specific variables that are used in
more generic shared roles/other pillar files.

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 - Raise error from yamlet renderer when an included file does not exist
+- Experimental inventory feature
 
 ## [1.10.0] - 2022-09-03
 

docs/configuration.md

@@ -108,3 +108,45 @@ The `salt_tower.unstable_enable_saltenv` flag modifies some options passed to th
 By setting `salt_tower.unstable_enable_saltenv` to `True`, Salt Tower will pass additional flags to the rendering pipeline, indicating that pillars are rendered. Engines, such as JINJA, will now look up files in `pillar_roots`. This can work well, when you Salt Tower base directory is the same as the pillar root directory.
 
 See issue [#11](https://github.com/jgraichen/salt-tower/issues/11) for more details.
+
+### salt_tower.enable_inventory
+
+**Experimental feature**: Enables the `inventory` mode. All pillar data within the `inventory:` subtree will not be returned in the final result. Instead, an additional context module is passed to templates, easing access to minion-scoped variables.
+
+This _inventory_ can be used to provide specialized, independent variable values to other pillar files such as roles. See the following example:
+
+```yaml title="tower.sls"
+base:
+  - inventory/*
+  - 'web*'
+      - role/web
+```
+
+```yaml title="inventory/vars.sls"
+inventory:
+  web-0:
+    ip:
+      public: 203.0.113.100
+    nginx:
+      server_name: example.org
+
+  web-1:
+    ip:
+      public: 203.0.113.110
+    nginx:
+      server_name: example.com
+```
+
+```yaml title="role/web.sls"
+states:
+  - nginx
+
+nginx:
+  config: |
+    server {
+      listen {{ inventory.get('ip:public') }}:80;
+      server_name {{ inventory.get('nginx:server_name') }};
+    }
+```
+
+The inventory can provide custom variables to be used in larger pillar files, or used in multiple roles.

salt_tower/pillar/tower.py

@@ -161,6 +161,10 @@ def run(self, top):
             else:
                 self._load_item(base, item)
 
+        if __opts__.get("salt_tower.enable_inventory", False):
+            if "inventory" in self:
+                del self["inventory"]
+
     def _match_minion(self, tgt):
         try:
             if hasattr(__grains__, "value"):
@@ -328,6 +332,9 @@ def _compile(  # pylint: disable=too-many-arguments
         ctx["tower"] = self
         ctx["env"] = self.env
 
+        if __opts__.get("salt_tower.enable_inventory", False):
+            ctx["inventory"] = Inventory(self)
+
         def render(path, context=None, renderer="text"):
             if isinstance(context, dict):
                 context = {**ctx, **context}
@@ -388,6 +395,16 @@ def render(path, context=None, renderer="text"):
             raise err
 
 
+class Inventory:  # pylint: disable=too-few-public-methods
+    def __init__(self, tower):
+        self._tower = tower
+
+    def get(self, key, minion=None, require=True, **kwargs):
+        if not minion:
+            minion = self._tower.minion_id
+        return self._tower.get(f"inventory:{minion}:{key}", require=require, **kwargs)
+
+
 class Formatter(string.Formatter):
     def __init__(self, tower):
         self._tower = tower

test/pillar/test_tower.py

@@ -707,3 +707,47 @@ def test_tower_jinja_import_roots(env):
     )
 
     assert env.ext_pillar() == {"foo": "pillar_root"}
+
+
+def test_tower_inventory_disabled(env):
+    env.setup(
+        {
+            "tower.sls": """
+            base:
+                - '*':
+                    - inventory.sls
+            """,
+            "inventory.sls": """
+            inventory:
+                test_master:
+                    key: 1
+            """,
+        }
+    )
+
+    assert env.ext_pillar() == {"inventory": {"test_master": {"key": 1}}}
+
+
+def test_tower_inventory_get(env):
+    env.opts.update({"salt_tower.enable_inventory": True})
+
+    env.setup(
+        {
+            "tower.sls": """
+            base:
+                - '*':
+                    - inventory.sls
+                    - init.sls
+            """,
+            "inventory.sls": """
+            inventory:
+                test_master:
+                    foo: 1
+            """,
+            "init.sls": """
+            bar: {{ inventory.get('foo') }}
+            """,
+        }
+    )
+
+    assert env.ext_pillar() == {"bar": 1}