feat(pluginpresets): resolve cross-preset ValueFrom.Ref (#1776)

Signed-off-by: Klaudiusz Fabryczny <klaudiusz.fabryczny@sap.com>

Author: k-fabryczny

charts/greenhouse/ci/test-values.yaml

@@ -15,6 +15,10 @@ global:
     expressionEvaluationEnabled: false
     integrationEnabled: false
     ociMirroringEnabled: false
+  # PluginPreset configuration for Greenhouse.
+  pluginPreset:
+    expressionEvaluationEnabled: true
+    integrationEnabled: true
   linkerd_enabled: false
   region: greenhouse
   registry: ghcr.io/cloudoperators/greenhouse

charts/greenhouse/values.yaml

@@ -23,6 +23,10 @@ global:
     expressionEvaluationEnabled: false
     integrationEnabled: false
     ociMirroringEnabled: false
+  # PluginPreset configuration for Greenhouse.
+  pluginPreset:
+    expressionEvaluationEnabled: true
+    integrationEnabled: true
 
 postgresqlng:
   enabled: true

charts/manager/ci/test-values.yaml

@@ -13,6 +13,9 @@ global:
     expressionEvaluationEnabled: false
     integrationEnabled: false
     ociMirroringEnabled: false
+  pluginPreset:
+    expressionEvaluationEnabled: true
+    integrationEnabled: true
 
 controllerManager:
   args:

charts/manager/templates/_helpers.tpl

@@ -117,3 +117,11 @@ Define postgresql helpers
 {{- define "plugin.ociMirroringEnabled" -}}
   {{- printf "%t" (required "global.plugin.ociMirroringEnabled missing" .Values.global.plugin.ociMirroringEnabled) }}
 {{- end }}
+{{/* Render the pluginPreset expression evaluation flag */}}
+{{- define "pluginPreset.expressionEvaluationEnabled" -}}
+  {{- printf "%t" (required "global.pluginPreset.expressionEvaluationEnabled missing" .Values.global.pluginPreset.expressionEvaluationEnabled) }}
+{{- end }}
+{{/* Render the pluginPreset integration enabled flag */}}
+{{- define "pluginPreset.integrationEnabled" -}}
+  {{- printf "%t" (required "global.pluginPreset.integrationEnabled missing" .Values.global.pluginPreset.integrationEnabled) }}
+{{- end }}

charts/manager/templates/manager/feature-flag.yaml

@@ -26,9 +26,19 @@ data:
       expressionEvaluationEnabled: false / true
       integrationEnabled: false / true
       ociMirroringEnabled: false / true
+    # enable pluginPreset features
+    # expressionEvaluationEnabled allows you to enable or disable CEL expression evaluation in PluginPreset
+    # when enabled, expressions in PluginPreset.spec.plugin.optionValues are evaluated before creating the Plugin
+    # integrationEnabled allows you to enable or disable ValueFrom.Ref resolution in PluginPreset
+    # when enabled, valueFrom.ref references in PluginPreset are resolved before creating the Plugin
+    pluginPreset: |
+      expressionEvaluationEnabled: false / true
   dex: |
     storage: {{ include "dex.backend" $ }}
   plugin: |
     expressionEvaluationEnabled: {{ include "plugin.expressionEvaluationEnabled" $ }}
     integrationEnabled: {{ include "plugin.integrationEnabled" $ }}
     ociMirroringEnabled: {{ include "plugin.ociMirroringEnabled" $ }}
+  pluginPreset: |
+    expressionEvaluationEnabled: {{ include "pluginPreset.expressionEvaluationEnabled" $ }}
+    integrationEnabled: {{ include "pluginPreset.integrationEnabled" $ }}

cmd/greenhouse/controllers.go

@@ -35,7 +35,7 @@ var knownControllers = map[string]func(controllerName string, mgr ctrl.Manager)
 
 	// Plugin controllers.
 	"plugin":       startPluginReconciler,
-	"pluginPreset": (&plugincontrollers.PluginPresetReconciler{}).SetupWithManager,
+	"pluginPreset": startPluginPresetReconciler,
 
 	"catalog":                 startCatalogReconciler,
 	"pluginDefinition":        startPluginDefinitionReconciler,
@@ -93,6 +93,13 @@ func startPluginReconciler(name string, mgr ctrl.Manager) error {
 	}).SetupWithManager(name, mgr)
 }
 
+func startPluginPresetReconciler(name string, mgr ctrl.Manager) error {
+	return (&plugincontrollers.PluginPresetReconciler{
+		ExpressionEvaluationEnabled: featureFlags.IsPresetExpressionEvaluationEnabled(),
+		IntegrationEnabled:          featureFlags.IsPresetIntegrationEnabled(),
+	}).SetupWithManager(name, mgr)
+}
+
 func startPluginDefinitionReconciler(name string, mgr ctrl.Manager) error {
 	return (&plugindefinitioncontroller.PluginDefinitionReconciler{
 		OCIMirroringEnabled: featureFlags.IsOCIMirroringEnabled(),

dev-env/dev.values.yaml

@@ -9,6 +9,9 @@ global:
     expressionEvaluationEnabled: true
     integrationEnabled: true
     ociMirroringEnabled: true
+  pluginPreset:
+    expressionEvaluationEnabled: true
+    integrationEnabled: true
 alerts:
   enabled: false
 certManager:

docs/reference/components/pluginpreset.md

@@ -33,6 +33,9 @@ spec:
     optionValues:
     - name: perses.sidecar.enabled
       value: true
+    - name: perses.ingress.host
+      expression: |
+        "perses.${global.greenhouse.clusterName}.example.com"
     pluginDefinitionRef:
       kind: ClusterPluginDefinition
       name: perses
@@ -86,8 +89,283 @@ spec:
 
 `.spec.deletionPolicy` is an optional field that specifies the behaviour when a PluginPreset is deleted. The possible values are `Delete` and `Retain`. If set to `Delete` (the default), all Plugins created by the PluginPreset will also be deleted when the PluginPreset is deleted. If set to `Retain`, the Plugins will remain after the PluginPreset is deleted or if the Cluster stops matching the selector.
 
+## CEL Expressions in OptionValues
+
+PluginPresets support CEL (Common Expression Language) expressions in `optionValues`. Expressions are evaluated during PluginPreset reconciliation, and the resulting Plugin contains only the resolved values with no expression fields remaining.
+
+Expressions use the `${...}` syntax to reference dynamic values:
+
+```yaml
+spec:
+  plugin:
+    optionValues:
+    - name: app.hostname
+      expression: |
+        "myapp.${global.greenhouse.clusterName}.example.com"
+```
+
+When this PluginPreset creates a Plugin for a cluster named `cluster-a`, the Plugin will contain:
+
+```yaml
+spec:
+  optionValues:
+  - name: app.hostname
+    value: "myapp.cluster-a.example.com"
+```
+
+### Available Variables
+
+| Variable                             |         Description        | Example Value                |
+|--------------------------------------|----------------------------|------------------------------|
+| `global.greenhouse.clusterName`      | Name of the target cluster | `cluster-a`                  |
+| `global.greenhouse.organizationName` | Organization namespace     | `my-org`                     |
+| `global.greenhouse.clusterNames`     | List of all cluster names  | `["cluster-a", "cluster-b"]` |
+| `global.greenhouse.teamNames`        | List of all team names     | `["team-1", "team-2"]`       |
+| `global.greenhouse.baseDomain`       | Base DNS domain            | `greenhouse.example.com`     |
+| `global.greenhouse.metadata.*`       | Cluster metadata labels    | `eu-de-1`                    |
+
+> :information_source: `global.greenhouse.metadata.*` values are derived from cluster labels prefixed with `metadata.greenhouse.sap/`. For example, the label `metadata.greenhouse.sap/region: eu-de-1` becomes available as `global.greenhouse.metadata.region`.
+
+### Examples
+
+**Hostname per cluster:**
+
+```yaml
+- name: ingress.host
+  expression: |
+    "service.${global.greenhouse.clusterName}.example.com"
+# Result for cluster "cluster-a": "service.cluster-a.example.com"
+```
+
+**Using cluster metadata:**
+
+```yaml
+- name: ingress.host
+  expression: |
+    "service.${global.greenhouse.metadata.region}.example.com"
+# Result: "service.eu-de-1.example.com"
+# Requires label metadata.greenhouse.sap/region on the cluster
+```
+
+**Combining variables:**
+
+```yaml
+- name: app.fqdn
+  expression: |
+    "${global.greenhouse.clusterName}-${global.greenhouse.organizationName}"
+# Result for cluster "cluster-a" in org "my-org": "cluster-a-my-org"
+```
+
+### Expressions in ClusterOptionOverrides
+
+Expressions can also be used in `clusterOptionOverrides`. Overrides are merged before expression evaluation, so override expressions are also resolved:
+
+```yaml
+spec:
+  plugin:
+    optionValues:
+    - name: app.mode
+      value: "standard"
+  clusterOptionOverrides:
+    - clusterName: special-cluster
+      overrides:
+      - name: app.hostname
+        expression: |
+          "special.${global.greenhouse.metadata.region}.example.com"
+```
+
+> :information_source: Expressions are only evaluated in PluginPresets.
+
+> :warning: CEL expressions on standalone Plugins are deprecated and will be removed in a future release. Use PluginPresets for expression evaluation.
+
+
+## Feature Flag
+
+CEL expression evaluation in PluginPresets is enabled only when the feature flag `pluginPreset.expressionEvaluationEnabled` is set to `true` in the Greenhouse feature flags ConfigMap.
+
+ By default, this flag is `false` if it is unset or invalid, and expressions are passed through as literal values without evaluation.
+
+```yaml
+# greenhouse-feature-flags ConfigMap
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: greenhouse-feature-flags
+  namespace: greenhouse
+data:
+  pluginPreset: |
+    expressionEvaluationEnabled: true
+```
+
+## ValueFrom References Between PluginPresets
+
+PluginPresets can reference option values from other PluginPresets using `valueFrom.ref`.
+This enables one PluginPreset to use resolved values from another, including values generated by CEL expressions.
+
+### Reference by Name
+
+```yaml
+# Source PluginPreset - generates a hostname per cluster
+apiVersion: greenhouse.sap/v1alpha1
+kind: PluginPreset
+metadata:
+  name: backend-preset
+spec:
+  plugin:
+    pluginDefinitionRef:
+      name: backend-service
+    optionValues:
+      - name: backend.hostname
+        expression: |
+          "backend.${global.greenhouse.clusterName}.example.com"
+  clusterSelector:
+    matchLabels:
+      env: production
+---
+# Consumer PluginPreset - references the backend hostname
+apiVersion: greenhouse.sap/v1alpha1
+kind: PluginPreset
+metadata:
+  name: frontend-preset
+spec:
+  plugin:
+    pluginDefinitionRef:
+      name: frontend-service
+    optionValues:
+      - name: frontend.backendUrl
+        valueFrom:
+          ref:
+            kind: PluginPreset
+            name: backend-preset
+            expression: |
+              ${spec.optionValues.filter(v, v.name == "backend.hostname")[0].value}
+  clusterSelector:
+    matchLabels:
+      env: production
+```
+
+The resulting Plugin will contain the resolved value. For example:
+
+```yaml
+# If the matching cluster is named "production-eu":
+spec:
+  optionValues:
+  - name: frontend.backendUrl
+    value: "backend.production-eu.example.com"
+```
+
+### Reference by Label Selector
+When multiple PluginPresets need to be referenced, use a label selector.
+The CEL expression is evaluated against each matching PluginPreset and results are collected into an array.
+
+
+```yaml
+# Multiple source PluginPresets with shared label
+apiVersion: greenhouse.sap/v1alpha1
+kind: PluginPreset
+metadata:
+  name: selector-source-a
+  namespace: demo
+  labels:
+    e2e.greenhouse.sap/selector-test: "true"
+spec:
+  plugin:
+    pluginDefinitionRef:
+      name: perses
+    releaseName: perses-sel-source-a
+    releaseNamespace: kube-monitoring
+    optionValues:
+      - name: source.endpoint
+        expression: |
+          "endpoint-a.${global.greenhouse.clusterName}.example.com"
+  clusterSelector:
+    matchLabels:
+      greenhouse.sap/cluster: kind-greenhouse-remote
+---
+apiVersion: greenhouse.sap/v1alpha1
+kind: PluginPreset
+metadata:
+  name: selector-source-b
+  namespace: demo
+  labels:
+    e2e.greenhouse.sap/selector-test: "true"
+spec:
+  plugin:
+    pluginDefinitionRef:
+      name: perses
+    releaseName: perses-sel-source-b
+    releaseNamespace: kube-monitoring
+    optionValues:
+      - name: source.endpoint
+        expression: |
+          "endpoint-b.${global.greenhouse.clusterName}.example.com"
+  clusterSelector:
+    matchLabels:
+      greenhouse.sap/cluster: kind-greenhouse-remote
+---
+apiVersion: greenhouse.sap/v1alpha1
+kind: PluginPreset
+metadata:
+  name: selector-consumer
+  namespace: demo
+spec:
+  plugin:
+    pluginDefinitionRef:
+      name: perses
+    releaseName: perses-sel-consumer
+    releaseNamespace: kube-monitoring
+    optionValues:
+      - name: consumer.endpoints
+        valueFrom:
+          ref:
+            kind: PluginPreset
+            selector:
+              matchLabels:
+                e2e.greenhouse.sap/selector-test: "true"
+            expression: |
+              ${spec.optionValues.filter(v, v.name == "source.endpoint")[0].value}
+  clusterSelector:
+    matchLabels:
+      greenhouse.sap/cluster: kind-greenhouse-remote
+```
+
+The consumer Plugin will receive an array of all resolved values:
+
+```yaml
+spec:
+  optionValues:
+  - name: consumer.endpoints
+    value: [ "endpoint-a.kind-greenhouse-remote.example.com",
+      "endpoint-b.kind-greenhouse-remote.example.com"]
+```
+
+### CEL Expression Syntax for References
+The expression field in valueFrom.ref supports multiple syntax styles:
+
+#### New simplified syntax
+```expression: spec.optionValues.filter(v, v.name == "my.value")[0].value```
+
+#### With ${...} wrapper
+```expression: ${spec.optionValues.filter(v, v.name == "my.value")[0].value}```
+
+#### Legacy syntax (backward compatible)
+```expression: object.spec.optionValues.filter(v, v.name == "my.value")[0].value```
+
+
+> :warning: ValueFrom references in PluginPresets only support referencing other PluginPresets (kind: PluginPreset). Referencing standalone Plugins is not supported.
+
+### Feature Flags
+Expression evaluation and ValueFrom.Ref resolution in PluginPresets are controlled by feature flags:
+
+```yaml
+# greenhouse-feature-flags ConfigMap
+pluginPreset: |
+  expressionEvaluationEnabled: true
+  integrationEnabled: true
+```
+
 ## Next Steps
 
 - [Managing Plugins for multiple clusters](./../../../user-guides/plugin/plugin-management)
 - [Plugin reference](./../plugin)
-- [PluginDefinition reference](./../plugindefinition)
+- [PluginDefinition reference](./../plugindefinition)