Add context variables for PipelineRun and TaskRun UIDs

A user may want to tag an oci image with the TaskRun or PipelineRun UIDs.
Currently, they can't do that because `metadata.uid` for TaskRuns and
PipelineRuns are not exposed.

In this PR, we add the UID context variable for TaskRuns and
PipelineRun. Users can now use `$(context.taskRun.uid)` and
`$(context.pipelineRun.uid)` to access and use UIDs.

In addition, we add validation for all context variables that are
supported so far -- `context.task.name`, `context.taskRun.name`,
`context.taskRun.namespace`, `context.taskRun.uid`,
`context.pipeline.name`, `context.pipelineRun.name`,
`context.pipelineRun.namespace`, `context.pipelineRun.uid`.

Partially fixes #2958

docs/variables.md

@@ -16,6 +16,7 @@ This page documents the variable substitions supported by `Tasks` and `Pipelines
 | `tasks.<taskName>.results.<resultName>` | The value of the `Task's` result. Can alter `Task` execution order within a `Pipeline`.) |
 | `context.pipelineRun.name` | The name of the `PipelineRun` that this `Pipeline` is running in. |
 | `context.pipelineRun.namespace` | The namespace of the `PipelineRun` that this `Pipeline` is running in. |
+| `context.pipelineRun.uid` | The uid of the `PipelineRun` that this `Pipeline` is running in. |
 | `context.pipeline.name` | The name of this `Pipeline` . |
 
 
@@ -33,6 +34,7 @@ This page documents the variable substitions supported by `Tasks` and `Pipelines
 | `credentials.path` | The path to credentials injected from Secrets with matching annotations. |
 | `context.taskRun.name` | The name of the `TaskRun` that this `Task` is running in. |
 | `context.taskRun.namespace` | The namespace of the `TaskRun` that this `Task` is running in. |
+| `context.taskRun.uid` | The uid of the `TaskRun` that this `Task` is running in. |
 | `context.task.name` | The name of this `Task`. |
 
 ### `PipelineResource` variables available in a `Task`

examples/v1beta1/pipelineruns/using_context_variables.yaml

@@ -0,0 +1,35 @@
+kind: PipelineRun
+apiVersion: tekton.dev/v1beta1
+metadata:
+  generateName: test-pipelinerun-
+spec:
+  pipelineSpec:
+    tasks:
+    - name: task1
+      params:
+      - name: pipeline-uid
+        value: "$(context.pipelineRun.uid)"
+      - name: pipeline-name
+        value: "$(context.pipeline.name)" 
+      - name: pipelineRun-name
+        value: "$(context.pipelineRun.name)"
+      - name: pipelineRun-name-uid
+        value: ["$(context.pipelineRun.name)", "$(context.pipelineRun.uid)"]
+      taskSpec:
+        params:
+        - name: pipeline-uid
+        - name: pipeline-name
+        - name: pipelineRun-name
+        steps:
+        - image: ubuntu
+          name: print-uid
+          script: |
+            echo "TaskRun UID: $(context.taskRun.uid)"
+            echo "PipelineRun UID from params: $(params.pipeline-uid)"
+        - image: ubuntu
+          name: print-names
+          script: |
+            echo "Task name: $(context.task.name)"
+            echo "TaskRun name: $(context.taskRun.name)"
+            echo "Pipeline name from params: $(params.pipeline-name)"
+            echo "PipelineRun name from params: $(params.pipelineRun-name)"

examples/v1beta1/taskruns/using_context_variables.yaml

@@ -0,0 +1,16 @@
+kind: TaskRun
+apiVersion: tekton.dev/v1beta1
+metadata:
+  generateName: test-taskrun-
+spec:
+  taskSpec:
+    steps:
+    - image: ubuntu
+      name: print-uid
+      script: |
+        echo "TaskRunUID name: $(context.taskRun.uid)"
+    - image: ubuntu
+      name: print-names
+      script: |
+        echo "Task name: $(context.task.name)"
+        echo "TaskRun name: $(context.taskRun.name)"

internal/builder/v1beta1/owner_reference.go

@@ -18,6 +18,7 @@ package builder
 
 import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
 )
 
 // OwnerReferenceOp is an operation which modifies an OwnerReference struct.
@@ -39,3 +40,8 @@ func Controller(o *metav1.OwnerReference) {
 func BlockOwnerDeletion(o *metav1.OwnerReference) {
 	o.BlockOwnerDeletion = &trueB
 }
+
+// OwnerUID sets the UID to the OwnerReference. 
+func OwnerUID(o *metav1.OwnerReference){
+	o.UID = types.UID("uid-1")
+}

internal/builder/v1beta1/pipeline.go

@@ -24,6 +24,7 @@ import (
 	resource "github.com/tektoncd/pipeline/pkg/apis/resource/v1alpha1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
 	"knative.dev/pkg/apis"
 )
 
@@ -353,6 +354,12 @@ func PipelineRun(name string, ops ...PipelineRunOp) *v1beta1.PipelineRun {
 
 	return pr
 }
+// PipelineRunUID sets the namespace on a PipelineRun
+func PipelineRunUID(uid string) PipelineRunOp {
+	return func(t *v1beta1.PipelineRun) {
+		t.ObjectMeta.UID = types.UID(uid)
+	}	
+} 
 
 // PipelineRunNamespace sets the namespace on a PipelineRun
 func PipelineRunNamespace(namespace string) PipelineRunOp {

internal/builder/v1beta1/task.go

@@ -24,6 +24,7 @@ import (
 	resource "github.com/tektoncd/pipeline/pkg/apis/resource/v1alpha1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
 	"knative.dev/pkg/apis"
 )
 
@@ -356,6 +357,13 @@ func TaskRunNamespace(namespace string) TaskRunOp {
 	}
 }
 
+// TaskRunUID sets the uid for the TaskRun.
+func TaskRunUID(uid string) TaskRunOp {
+	return func(t *v1beta1.TaskRun) {
+		t.ObjectMeta.UID = types.UID(uid)
+	}
+}
+
 // TaskRunStatus sets the TaskRunStatus to tshe TaskRun
 func TaskRunStatus(ops ...TaskRunStatusOp) TaskRunOp {
 	return func(tr *v1beta1.TaskRun) {

pkg/apis/pipeline/v1beta1/task_validation.go

@@ -242,7 +242,7 @@ func ValidateParameterVariables(steps []Step, params []ParamSpec) *apis.FieldErr
 		}
 	}
 
-	if err := validateVariables(steps, "params", parameterNames); err != nil {
+	if err := ValidateVariables(steps, "params", parameterNames); err != nil {
 		return err
 	}
 	return validateArrayUsage(steps, "params", arrayParameterNames)
@@ -263,7 +263,7 @@ func ValidateResourcesVariables(steps []Step, resources *TaskResources) *apis.Fi
 			resourceNames.Insert(r.Name)
 		}
 	}
-	return validateVariables(steps, "resources.(?:inputs|outputs)", resourceNames)
+	return ValidateVariables(steps, "resources.(?:inputs|outputs)", resourceNames)
 }
 
 func validateArrayUsage(steps []Step, prefix string, vars sets.String) *apis.FieldError {
@@ -310,7 +310,7 @@ func validateArrayUsage(steps []Step, prefix string, vars sets.String) *apis.Fie
 	return nil
 }
 
-func validateVariables(steps []Step, prefix string, vars sets.String) *apis.FieldError {
+func ValidateVariables(steps []Step, prefix string, vars sets.String) *apis.FieldError {
 	for _, step := range steps {
 		if err := validateTaskVariable("name", step.Name, prefix, vars); err != nil {
 			return err

pkg/reconciler/pipelinerun/pipelinerun.go

@@ -97,6 +97,9 @@ const (
 	// ReasonCouldntCancel indicates that a PipelineRun was cancelled but attempting to update
 	// all of the running TaskRuns as cancelled failed.
 	ReasonCouldntCancel = "PipelineRunCouldntCancel"
+	// ReasonFailedContextValidation indicates that the reason for failure is that the PipelineRun
+	// failed to resolve the contexts.
+	ReasonFailedContextValidation = "ReasonFailedContextValidation"
 )
 
 // Reconciler implements controller.Reconciler for Configuration resources.
@@ -362,6 +365,14 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1beta1.PipelineRun) err
 		return controller.NewPermanentError(err)
 	}
 
+	// Ensure that the context variables in the PipelineRun parameters are valid.
+	if err := resources.ValidateContextVariables(pipelineSpec, pr); err != nil {
+		pr.Status.MarkFailed(ReasonFailedContextValidation,
+			"PipelineRun %s/%s parameters has invalid context variable %s/%s's: %s",
+			pr.Namespace, pr.Name, pr.Namespace, pipelineMeta.Name, err)
+		return controller.NewPermanentError(err)
+	}	
+
 	// Ensure that the ServiceAccountNames defined correct.
 	if err := resources.ValidateServiceaccountMapping(pipelineSpec, pr); err != nil {
 		pr.Status.MarkFailed(ReasonInvalidServiceAccountMapping,