adding label to identify a finally taskRun in a pipeline

A label is added to a taskRun for a task which is part of the finally section.
The label added is tekton.dev/finallyTask and set to true for a finally task.

docs/labels.md

@@ -80,6 +80,12 @@ Tekton automatically adds labels to Tekton entities as described in the followin
 			<td>No propagation.</td>
 			<td>Name of the <code>TaskRun</code> that created the <code>Pod</code>.</td>
 		</tr>
+		<tr>
+			<td><code>tekton.dev/finallyTask</code></td>
+			<td><code>TaskRuns</code> that are created for a <code>finally tasks</code> during the execution of a <code>PipelineRun</code>.</td>
+			<td><code>TaskRuns, Pods</code></td>
+			<td><code>true</code></td>
+		</tr>
 		<tr>
 			<td><code>app.kubernetes.io/instance</code>, <code>app.kubernetes.io/component</code></td>
 			<td><code>Pods</code>, <code>StatefulSets</code> (Affinity Assistant)</td>

pkg/apis/pipeline/register.go

@@ -48,6 +48,9 @@ const (
 
 	// RunKey is used as the label identifier for a Run
 	RunKey = "/run"
+
+	// FinallyLabelKey is used as the label identifier for a Finally task
+	FinallyLabelKey = "/finallyTask"
 )
 
 var (

pkg/reconciler/pipelinerun/pipelinerun.go

@@ -929,6 +929,14 @@ func combineTaskRunAndTaskSpecLabels(pr *v1beta1.PipelineRun, pipelineTask *v1be
 			labels[key] = value
 		}
 	}
+
+	// check if a task is part of the finally section, add a label to identify it during the runtime
+	for _, f := range pr.Status.PipelineSpec.Finally {
+		if pipelineTask.Name == f.Name {
+			labels[pipeline.GroupName+pipeline.FinallyLabelKey] = "true"
+			break
+		}
+	}
 	return labels
 }
 

pkg/reconciler/pipelinerun/pipelinerun_test.go

@@ -5448,6 +5448,7 @@ func TestReconciler_ReconcileKind_PipelineTaskContext(t *testing.T) {
 		tb.TaskRunLabel("tekton.dev/pipeline", pipelineName),
 		tb.TaskRunLabel("tekton.dev/pipelineRun", pipelineRunName),
 		tb.TaskRunLabel("tekton.dev/pipelineTask", "finaltask"),
+		tb.TaskRunLabel("tekton.dev/finallyTask", "true"),
 		tb.TaskRunSpec(
 			tb.TaskRunTaskRef("finaltask"),
 			tb.TaskRunServiceAccountName("test-sa"),
@@ -5681,6 +5682,7 @@ func TestReconcileWithTaskResultsInFinalTasks(t *testing.T) {
 				"tekton.dev/pipeline":     "test-pipeline",
 				"tekton.dev/pipelineRun":  "test-pipeline-run-final-task-results",
 				"tekton.dev/pipelineTask": "final-task-1",
+				"tekton.dev/finallyTask":  "true",
 			},
 			Annotations: map[string]string{},
 		},