[TEP-0144] Validate PipelineRun for Param Enum

Part of [#7270][#7270]. In [TEP-0144][tep-0144] we proposed a new `enum` field to support built-in param input validation.

This commit adds validation logic for PipelineRun against Param Enum

/kind feature

[#7270]: #7270
[tep-0144]: https://github.com/tektoncd/community/blob/main/teps/0144-param-enum.md

config/config-feature-flags.yaml

@@ -127,5 +127,4 @@ data:
   # This feature is in preview mode and not implemented yet. Please check #7259 for updates.
   enable-step-actions: "false"
   # Setting this flag to "true" will enable the built-in param input validation via param enum.
-  # NOTE (#7270): this feature is still under development and not yet functional.
   enable-param-enum: "false"

docs/additional-configs.md

@@ -317,6 +317,7 @@ Features currently in "alpha" are:
 | [Coschedule](./affinityassistants.md)                                                               | [TEP-0135](https://github.com/tektoncd/community/blob/main/teps/0135-coscheduling-pipelinerun-pods.md)                        | N/A                                 |`coschedule`                                |
 | [keep pod on cancel](./taskruns.md#cancelling-a-taskrun)                                            | N/A |  v0.52 | keep-pod-on-cancel |
 | [CEL in WhenExpression](./taskruns.md#cancelling-a-taskrun)                                            | [TEP-0145](https://github.com/tektoncd/community/blob/main/teps/0145-cel-in-whenexpression.md) |  N/A | enable-cel-in-whenexpression |
+| [Param Enum](./taskruns.md#parameter-enums)                                            | [TEP-0144](https://github.com/tektoncd/community/blob/main/teps/0144-param-enum.md) |  N/A | `enable-param-enum` |
 
 ### Beta Features
 

docs/pipeline-api.md

@@ -1997,6 +1997,9 @@ associated Pipeline is an invalid graph (a.k.a wrong order, cycle, …)</p>
 </tr><tr><td><p>&#34;InvalidMatrixParameterTypes&#34;</p></td>
 <td><p>ReasonInvalidMatrixParameterTypes indicates a matrix contains invalid parameter types</p>
 </td>
+</tr><tr><td><p>&#34;InvalidParamValue&#34;</p></td>
+<td><p>PipelineRunReasonInvalidParamValue indicates that the PipelineRun Param input value is not allowed.</p>
+</td>
 </tr><tr><td><p>&#34;InvalidTaskResultReference&#34;</p></td>
 <td><p>ReasonInvalidTaskResultReference indicates a task result was declared
 but was not initialized by that task</p>

docs/pipelineruns.md

@@ -271,6 +271,18 @@ case is when your CI system autogenerates `PipelineRuns` and it has `Parameters`
 provide to all `PipelineRuns`. Because you can pass in extra `Parameters`, you don't have to
 go through the complexity of checking each `Pipeline` and providing only the required params.
 
+#### Parameter Enums
+
+> :seedling: **`enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
+
+If a `Parameter` is guarded by `Enum` in the `Pipeline`, you can only provide `Parameter` values in the `PipelineRun` that are predefined in the `Param.Enum` in the `Pipeline`. The `PipelineRun` will fail with reason `InvalidParamValue` otherwise. 
+
+Tekton will also the validate the `param` values passed to any referenced `Tasks` (via `taskRef`) if `Enum` is specified for the `Task`. The `PipelineRun` will fail with reason `InvalidParamValue` if `Enum` validation is failed for any of the `PipelineTask`. 
+
+You can also specify `Enum` in an embedded `Pipeline` in a `PipelineRun`. The same `Param` validation will be executed in this scenario.
+
+See more details in [Param.Enum](./pipelines.md#param-enum).
+
 #### Propagated Parameters
 
 When using an inlined spec, parameters from the parent `PipelineRun` will be

docs/pipelines.md

@@ -272,11 +272,77 @@ spec:
 ```
 
 #### Param enum
-> :seedling: **Specifying `enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
+> :seedling: **`enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
 
-> :seedling: This feature is WIP and not yet supported/implemented. Documentation to be completed.
+Parameter declarations can include `enum` which is a predefine set of valid values that can be accepted by the `Pipeline` `Param`. For example, the valid/allowed values for `Param` "message" is bounded to `v1` and `v2`:
 
-Parameter declarations can include `enum` which is a predefine set of valid values that can be accepted by the `Pipeline`.
+``` yaml
+apiVersion: tekton.dev/v1
+kind: Pipeline
+metadata:
+  name: pipeline-param-enum
+spec:
+  params:
+  - name: message
+    enum: ["v1", "v2"]
+    default: "v1"
+  tasks:
+  - name: task1
+    params:
+      - name: message
+        value: $(params.message)
+    steps:
+    - name: build
+      image: bash:3.2
+      script: |
+        echo "$(params.message)"
+```
+
+If the `Param` value passed in by `PipelineRun` is **NOT** in the predefined `enum` list, the `PipelineRun` will fail with reason `InvalidParamValue`.
+
+If a `PipelineTask` references a `Task` with `enum`, the `enums` specified in the Pipeline `spec.params` (pipeline-level `enum`) must be
+a **subset** of the `enums` specified in the referenced `Task` (task-level `enum`). Note that an empty pipeline-level `enum` is invalid 
+in this scenario since an empty `enum` set indicates a "universal set" which allows all possible values. In the below example, the referenced `Task` accepts `v1` and `v2` as valid values, the `Pipeline` further restricts the valid values to `v1`.
+
+``` yaml
+apiVersion: tekton.dev/v1
+kind: Task
+metadata:
+  name: param-enum-demo
+spec:
+  params:
+  - name: message
+    type: string
+    enum: ["v1", "v2"]
+  steps:
+  - name: build
+    image: bash:latest
+    script: |
+      echo "$(params.message)"
+```
+
+``` yaml
+apiVersion: tekton.dev/v1
+kind: Pipeline
+metadata:
+  name: pipeline-param-enum
+spec:
+  params:
+  - name: message
+    enum: ["v1"]  # note that an empty enum set is invalid
+  tasks:
+  - name: task1
+    params:
+      - name: message
+        value: $(params.message)
+    taskRef:
+      name: param-enum-demo
+```
+
+Tekton validates user-provided values in a `PipelineRun` against the `enum` specified in the `PipelineSpec.params`. Tekton also validates
+any resolved `param` value against the `enum` specified in each `PipelineTask` before creating the `TaskRun`.
+
+See usage in this [example](../examples/v1/pipelineruns/alpha/param-enum.yaml)
 
 ## Adding `Tasks` to the `Pipeline`
 

docs/taskruns.md

@@ -404,9 +404,7 @@ go through the complexity of checking each `Task` and providing only the require
 
 #### Parameter Enums
 
-> :seedling: **Specifying `enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
-
-> :seedling: This feature is WIP and not yet supported/implemented. Documentation to be completed.
+> :seedling: **`enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
 
 If a `Parameter` is guarded by `Enum` in the `Task`, you can only provide `Parameter` values in the `TaskRun` that are predefined in the `Param.Enum` in the `Task`. The `TaskRun` will fail with reason `InvalidParamValue` otherwise.
 

docs/tasks.md

@@ -713,9 +713,7 @@ spec:
 ```
 
 #### Param enum
-> :seedling: **Specifying `enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
-
-> :seedling: This feature is WIP and not yet supported/implemented. Documentation to be completed.
+> :seedling: **`enum` is an [alpha](additional-configs.md#alpha-features) feature.** The `enable-param-enum` feature flag must be set to `"true"` to enable this feature.
 
 Parameter declarations can include `enum` which is a predefine set of valid values that can be accepted by the `Param`. For example, the valid/allowed values for `Param` "message" is bounded to `v1`, `v2` and `v3`:
 

examples/v1/pipelineruns/alpha/param-enum.yaml

@@ -0,0 +1,42 @@
+apiVersion: tekton.dev/v1
+kind: Task
+metadata:
+  name: task-param-enum
+spec:
+  params:
+  - name: message
+    type: string
+    enum: ["v1", "v2", "v3"]
+  steps:
+  - name: build
+    image: bash:latest
+    script: |
+      echo "$(params.message)"
+---
+apiVersion: tekton.dev/v1
+kind: Pipeline
+metadata:
+  name: pipeline-param-enum
+spec:
+  params:
+  - name: message
+    enum: ["v1", "v2"]
+    default: "v1"
+  tasks:
+  - name: task1
+    params:
+      - name: message
+        value: $(params.message)
+    taskRef:
+      name: task-param-enum
+---
+apiVersion: tekton.dev/v1
+kind: PipelineRun
+metadata:
+  name: pipelinerun-param-enum
+spec:
+  pipelineRef:
+    name: pipeline-param-enum
+  params:
+    - name: message
+      value: "v1"

pkg/apis/pipeline/v1/pipelinerun_types.go

@@ -408,6 +408,8 @@ const (
 	PipelineRunReasonCreateRunFailed PipelineRunReason = "CreateRunFailed"
 	// ReasonCELEvaluationFailed indicates the pipeline fails the CEL evaluation
 	PipelineRunReasonCELEvaluationFailed PipelineRunReason = "CELEvaluationFailed"
+	// PipelineRunReasonInvalidParamValue indicates that the PipelineRun Param input value is not allowed.
+	PipelineRunReasonInvalidParamValue PipelineRunReason = "InvalidParamValue"
 )
 
 func (t PipelineRunReason) String() string {

pkg/reconciler/pipelinerun/pipelinerun.go

@@ -487,6 +487,16 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1.PipelineRun, getPipel
 		return controller.NewPermanentError(err)
 	}
 
+	if config.FromContextOrDefaults(ctx).FeatureFlags.EnableParamEnum {
+		if err := taskrun.ValidateEnumParam(ctx, pr.Spec.Params, pipelineSpec.Params); err != nil {
+			logger.Errorf("PipelineRun %q Param Enum validation failed: %v", pr.Name, err)
+			pr.Status.MarkFailed(v1.PipelineRunReasonInvalidParamValue.String(),
+				"PipelineRun %s/%s parameters have invalid value: %s",
+				pr.Namespace, pr.Name, err)
+			return controller.NewPermanentError(err)
+		}
+	}
+
 	// Ensure that the keys of an object param declared in PipelineSpec are not missed in the PipelineRunSpec
 	if err = resources.ValidateObjectParamRequiredKeys(pipelineSpec.Params, pr.Spec.Params); err != nil {
 		// This Run has failed, so we need to mark it as failed and stop reconciling it
@@ -521,6 +531,12 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1.PipelineRun, getPipel
 		return controller.NewPermanentError(err)
 	}
 
+	// Make a deep copy of the Pipeline and its Tasks before value substution.
+	// This is used to find referenced pipeline-level params at each PipelineTask when validate param enum subset requirement
+	originalPipeline := pipelineSpec.DeepCopy()
+	originalTasks := originalPipeline.Tasks
+	originalTasks = append(originalTasks, originalPipeline.Finally...)
+
 	// Apply parameter substitution from the PipelineRun
 	pipelineSpec = resources.ApplyParameters(ctx, pipelineSpec, pr)
 	pipelineSpec = resources.ApplyContexts(pipelineSpec, pipelineMeta.Name, pr)
@@ -615,14 +631,22 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1.PipelineRun, getPipel
 		pipelineRunFacts.TimeoutsState.PipelineTimeout = &pipelineTimeout
 	}
 
-	for _, rpt := range pipelineRunFacts.State {
+	for i, rpt := range pipelineRunFacts.State {
 		if !rpt.IsCustomTask() {
 			err := taskrun.ValidateResolvedTask(ctx, rpt.PipelineTask.Params, rpt.PipelineTask.Matrix, rpt.ResolvedTask)
 			if err != nil {
 				logger.Errorf("Failed to validate pipelinerun %q with error %v", pr.Name, err)
 				pr.Status.MarkFailed(v1.PipelineRunReasonFailedValidation.String(), err.Error())
 				return controller.NewPermanentError(err)
 			}
+
+			if config.FromContextOrDefaults(ctx).FeatureFlags.EnableParamEnum {
+				if err := resources.ValidateParamEnumSubset(originalTasks[i].Params, pipelineSpec.Params, rpt.ResolvedTask); err != nil {
+					logger.Errorf("Failed to validate pipelinerun %q with error %v", pr.Name, err)
+					pr.Status.MarkFailed(v1.PipelineRunReasonFailedValidation.String(), err.Error())
+					return controller.NewPermanentError(err)
+				}
+			}
 		}
 	}
 
@@ -864,10 +888,24 @@ func (c *Reconciler) createTaskRuns(ctx context.Context, rpt *resources.Resolved
 	defer span.End()
 	var taskRuns []*v1.TaskRun
 	var matrixCombinations []v1.Params
-
 	if rpt.PipelineTask.IsMatrixed() {
 		matrixCombinations = rpt.PipelineTask.Matrix.FanOut()
 	}
+	// validate the param values meet resolved Task Param Enum requirements before creating TaskRuns
+	if config.FromContextOrDefaults(ctx).FeatureFlags.EnableParamEnum {
+		for i := range rpt.TaskRunNames {
+			var params v1.Params
+			if len(matrixCombinations) > i {
+				params = matrixCombinations[i]
+			}
+			params = append(params, rpt.PipelineTask.Params...)
+			if err := taskrun.ValidateEnumParam(ctx, params, rpt.ResolvedTask.TaskSpec.Params); err != nil {
+				err = fmt.Errorf("Invalid param value from PipelineTask \"%s\": %w", rpt.PipelineTask.Name, err)
+				pr.Status.MarkFailed(v1.PipelineRunReasonInvalidParamValue.String(), err.Error())
+				return nil, controller.NewPermanentError(err)
+			}
+		}
+	}
 	for i, taskRunName := range rpt.TaskRunNames {
 		var params v1.Params
 		if len(matrixCombinations) > i {