refactoring pipelinerunstate

Introducing PipelineRunFacts as a combination of PipelineRunState, DAG
Graph, and finally Graph. This simplifies function definitions without having
to pass graphs to PipelineRunState attributes.

pkg/reconciler/pipelinerun/pipelinerun.go

@@ -427,7 +427,15 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1beta1.PipelineRun) err
 		return controller.NewPermanentError(err)
 	}
 
-	for _, rprt := range pipelineRunState {
+	// Build PipelineRunFacts with a list of resolved pipeline tasks,
+	// dag tasks graph and final tasks graph
+	pipelineRunFacts := &resources.PipelineRunFacts{
+		State:           pipelineRunState,
+		TasksGraph:      d,
+		FinalTasksGraph: dfinally,
+	}
+
+	for _, rprt := range pipelineRunFacts.State {
 		err := taskrun.ValidateResolvedTaskResources(rprt.PipelineTask.Params, rprt.ResolvedTaskResources)
 		if err != nil {
 			logger.Errorf("Failed to validate pipelinerun %q with error %v", pr.Name, err)
@@ -436,7 +444,7 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1beta1.PipelineRun) err
 		}
 	}
 
-	if pipelineRunState.IsBeforeFirstTaskRun() {
+	if pipelineRunFacts.State.IsBeforeFirstTaskRun() {
 		if pr.HasVolumeClaimTemplate() {
 			// create workspace PVC from template
 			if err = c.pvcHandler.CreatePersistentVolumeClaimsForWorkspaces(pr.Spec.Workspaces, pr.GetOwnerReference(), pr.Namespace); err != nil {
@@ -466,11 +474,11 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1beta1.PipelineRun) err
 		return controller.NewPermanentError(err)
 	}
 
-	if err := c.runNextSchedulableTask(ctx, pr, d, dfinally, pipelineRunState, as); err != nil {
+	if err := c.runNextSchedulableTask(ctx, pr, pipelineRunFacts, as); err != nil {
 		return err
 	}
 
-	after := pipelineRunState.GetPipelineConditionStatus(pr, logger, d, dfinally)
+	after := pipelineRunFacts.GetPipelineConditionStatus(pr, logger)
 	switch after.Status {
 	case corev1.ConditionTrue:
 		pr.Status.MarkSucceeded(after.Reason, after.Message)
@@ -481,37 +489,28 @@ func (c *Reconciler) reconcile(ctx context.Context, pr *v1beta1.PipelineRun) err
 	}
 	// Read the condition the way it was set by the Mark* helpers
 	after = pr.Status.GetCondition(apis.ConditionSucceeded)
-	pr.Status.TaskRuns = pipelineRunState.GetTaskRunsStatus(pr)
-	pr.Status.SkippedTasks = pipelineRunState.GetSkippedTasks(pr, d)
+	pr.Status.TaskRuns = pipelineRunFacts.State.GetTaskRunsStatus(pr)
+	pr.Status.SkippedTasks = pipelineRunFacts.GetSkippedTasks()
 	logger.Infof("PipelineRun %s status is being set to %s", pr.Name, after)
 	return nil
 }
 
 // runNextSchedulableTask gets the next schedulable Tasks from the dag based on the current
 // pipeline run state, and starts them
 // after all DAG tasks are done, it's responsible for scheduling final tasks and start executing them
-func (c *Reconciler) runNextSchedulableTask(ctx context.Context, pr *v1beta1.PipelineRun, d *dag.Graph, dfinally *dag.Graph, pipelineRunState resources.PipelineRunState, as artifacts.ArtifactStorageInterface) error {
+func (c *Reconciler) runNextSchedulableTask(ctx context.Context, pr *v1beta1.PipelineRun, pipelineRunFacts *resources.PipelineRunFacts, as artifacts.ArtifactStorageInterface) error {
 
 	logger := logging.FromContext(ctx)
 	recorder := controller.GetEventRecorder(ctx)
 
-	var nextRprts []*resources.ResolvedPipelineRunTask
-
-	// when pipeline run is stopping, do not schedule any new task and only
-	// wait for all running tasks to complete and report their status
-	if !pipelineRunState.IsStopping(d) {
-		// candidateTasks is initialized to DAG root nodes to start pipeline execution
-		// candidateTasks is derived based on successfully finished tasks and/or skipped tasks
-		candidateTasks, err := dag.GetSchedulable(d, pipelineRunState.SuccessfulOrSkippedDAGTasks(d)...)
-		if err != nil {
-			logger.Errorf("Error getting potential next tasks for valid pipelinerun %s: %v", pr.Name, err)
-			return controller.NewPermanentError(err)
-		}
-		// nextRprts holds a list of pipeline tasks which should be executed next
-		nextRprts = pipelineRunState.GetNextTasks(candidateTasks)
+	// nextRprts holds a list of pipeline tasks which should be executed next
+	nextRprts, err := pipelineRunFacts.DAGExecutionQueue()
+	if err != nil {
+		logger.Errorf("Error getting potential next tasks for valid pipelinerun %s: %v", pr.Name, err)
+		return controller.NewPermanentError(err)
 	}
 
-	resolvedResultRefs, err := resources.ResolveResultRefs(pipelineRunState, nextRprts)
+	resolvedResultRefs, err := resources.ResolveResultRefs(pipelineRunFacts.State, nextRprts)
 	if err != nil {
 		logger.Infof("Failed to resolve all task params for %q with error %v", pr.Name, err)
 		pr.Status.MarkFailed(ReasonFailedValidation, err.Error())
@@ -521,10 +520,10 @@ func (c *Reconciler) runNextSchedulableTask(ctx context.Context, pr *v1beta1.Pip
 	resources.ApplyTaskResults(nextRprts, resolvedResultRefs)
 
 	// GetFinalTasks only returns tasks when a DAG is complete
-	nextRprts = append(nextRprts, pipelineRunState.GetFinalTasks(d, dfinally)...)
+	nextRprts = append(nextRprts, pipelineRunFacts.GetFinalTasks()...)
 
 	for _, rprt := range nextRprts {
-		if rprt == nil || rprt.Skip(pipelineRunState, d) {
+		if rprt == nil || rprt.Skip(pipelineRunFacts) {
 			continue
 		}
 		if rprt.ResolvedConditionChecks == nil || rprt.ResolvedConditionChecks.IsSuccess() {

pkg/reconciler/pipelinerun/resources/pipelinerunresolution.go

@@ -30,7 +30,6 @@ import (
 	"github.com/tektoncd/pipeline/pkg/contexts"
 	"github.com/tektoncd/pipeline/pkg/list"
 	"github.com/tektoncd/pipeline/pkg/names"
-	"github.com/tektoncd/pipeline/pkg/reconciler/pipeline/dag"
 	"github.com/tektoncd/pipeline/pkg/reconciler/taskrun/resources"
 )
 
@@ -134,17 +133,15 @@ func (t ResolvedPipelineRunTask) IsStarted() bool {
 	return true
 }
 
-func (t *ResolvedPipelineRunTask) checkParentsDone(state PipelineRunState, d *dag.Graph) bool {
-	stateMap := state.ToMap()
+func (t *ResolvedPipelineRunTask) checkParentsDone(facts *PipelineRunFacts) bool {
+	stateMap := facts.State.ToMap()
 	// check if parent tasks are done executing,
 	// if any of the parents is not yet scheduled or still running,
 	// wait for it to complete before evaluating when expressions
-	node := d.Nodes[t.PipelineTask.Name]
-	if isTaskInGraph(t.PipelineTask.Name, d) {
-		for _, p := range node.Prev {
-			if !stateMap[p.Task.HashKey()].IsDone() {
-				return false
-			}
+	node := facts.TasksGraph.Nodes[t.PipelineTask.Name]
+	for _, p := range node.Prev {
+		if !stateMap[p.Task.HashKey()].IsDone() {
+			return false
 		}
 	}
 	return true
@@ -156,7 +153,12 @@ func (t *ResolvedPipelineRunTask) checkParentsDone(state PipelineRunState, d *da
 // (3) its parent task was skipped
 // (4) Pipeline is in stopping state (one of the PipelineTasks failed)
 // Note that this means Skip returns false if a conditionCheck is in progress
-func (t *ResolvedPipelineRunTask) Skip(state PipelineRunState, d *dag.Graph) bool {
+func (t *ResolvedPipelineRunTask) Skip(facts *PipelineRunFacts) bool {
+	// finally tasks are never skipped. If this is a final task, return false
+	if facts.isFinalTask(t.PipelineTask.Name) {
+		return false
+	}
+
 	// it already has TaskRun associated with it - PipelineTask not skipped
 	if t.IsStarted() {
 		return false
@@ -170,7 +172,7 @@ func (t *ResolvedPipelineRunTask) Skip(state PipelineRunState, d *dag.Graph) boo
 	}
 
 	// Check if the when expressions are false, based on the input's relationship to the values
-	if t.checkParentsDone(state, d) {
+	if t.checkParentsDone(facts) {
 		if len(t.PipelineTask.WhenExpressions) > 0 {
 			if !t.PipelineTask.WhenExpressions.HaveVariables() {
 				if !t.PipelineTask.WhenExpressions.AllowsExecution() {
@@ -181,19 +183,17 @@ func (t *ResolvedPipelineRunTask) Skip(state PipelineRunState, d *dag.Graph) boo
 	}
 
 	// Skip the PipelineTask if pipeline is in stopping state
-	if isTaskInGraph(t.PipelineTask.Name, d) && state.IsStopping(d) {
+	if facts.IsStopping() {
 		return true
 	}
 
-	stateMap := state.ToMap()
+	stateMap := facts.State.ToMap()
 	// Recursively look at parent tasks to see if they have been skipped,
 	// if any of the parents have been skipped, skip as well
-	node := d.Nodes[t.PipelineTask.Name]
-	if isTaskInGraph(t.PipelineTask.Name, d) {
-		for _, p := range node.Prev {
-			if stateMap[p.Task.HashKey()].Skip(state, d) {
-				return true
-			}
+	node := facts.TasksGraph.Nodes[t.PipelineTask.Name]
+	for _, p := range node.Prev {
+		if stateMap[p.Task.HashKey()].Skip(facts) {
+			return true
 		}
 	}
 	return false

pkg/reconciler/pipelinerun/resources/pipelinerunresolution_test.go

@@ -835,7 +835,7 @@ func TestIsSkipped(t *testing.T) {
 
 	for _, tc := range tcs {
 		t.Run(tc.name, func(t *testing.T) {
-			dag, err := DagFromState(tc.state)
+			d, err := DagFromState(tc.state)
 			if err != nil {
 				t.Fatalf("Could not get a dag from the TC state %#v: %v", tc.state, err)
 			}
@@ -844,7 +844,12 @@ func TestIsSkipped(t *testing.T) {
 			if rprt == nil {
 				t.Fatalf("Could not get task %s from the state: %v", tc.taskName, tc.state)
 			}
-			isSkipped := rprt.Skip(tc.state, dag)
+			facts := PipelineRunFacts{
+				State:           tc.state,
+				TasksGraph:      d,
+				FinalTasksGraph: &dag.Graph{},
+			}
+			isSkipped := rprt.Skip(&facts)
 			if d := cmp.Diff(isSkipped, tc.expected); d != "" {
 				t.Errorf("Didn't get expected isSkipped %s", diff.PrintWantGot(d))
 			}