api/nfd: extend NodeFeatureGroup to support vars

Add Vars and VarsTemplate fields to the NodeFeatureGroup spec. This
enables construction of complex rule hierarchies by making it possible
to reference/use results of preceding rules when evaluating a rule.

Author: marquiz

api/nfd/v1alpha1/types.go

@@ -183,6 +183,17 @@ type GroupRule struct {
 	// Name of the rule.
 	Name string `json:"name"`
 
+	// Vars is the variables to store if the rule matches. Variables can be
+	// referenced from other rules enabling more complex rule hierarchies.
+	// +optional
+	Vars map[string]string `json:"vars"`
+
+	// VarsTemplate specifies a template to expand for dynamically generating
+	// multiple variables. Data (after template expansion) must be keys with an
+	// optional value (<key>[=<value>]) separated by newlines.
+	// +optional
+	VarsTemplate string `json:"varsTemplate"`
+
 	// MatchFeatures specifies a set of matcher terms all of which must match.
 	// +optional
 	MatchFeatures FeatureMatcher `json:"matchFeatures"`

api/nfd/v1alpha1/zz_generated.deepcopy.go

@@ -356,6 +356,19 @@ spec:
                     name:
                       description: Name of the rule.
                       type: string
+                    vars:
+                      additionalProperties:
+                        type: string
+                      description: |-
+                        Vars is the variables to store if the rule matches. Variables can be
+                        referenced from other rules enabling more complex rule hierarchies.
+                      type: object
+                    varsTemplate:
+                      description: |-
+                        VarsTemplate specifies a template to expand for dynamically generating
+                        multiple variables. Data (after template expansion) must be keys with an
+                        optional value (<key>[=<value>]) separated by newlines.
+                      type: string
                   required:
                   - name
                   type: object

deployment/base/nfd-crds/nfd-api-crds.yaml

@@ -356,6 +356,19 @@ spec:
                     name:
                       description: Name of the rule.
                       type: string
+                    vars:
+                      additionalProperties:
+                        type: string
+                      description: |-
+                        Vars is the variables to store if the rule matches. Variables can be
+                        referenced from other rules enabling more complex rule hierarchies.
+                      type: object
+                    varsTemplate:
+                      description: |-
+                        VarsTemplate specifies a template to expand for dynamically generating
+                        multiple variables. Data (after template expansion) must be keys with an
+                        optional value (<key>[=<value>]) separated by newlines.
+                      type: string
                   required:
                   - name
                   type: object