TEP-0121: Reconciler Implementation

Prior to this commit, `retries` logic for TaskRun is handled by
Tekton `PipelineRun` reconciler. This commit delegates the retries
implementation for `TaskRun` to the `TaskRun` reconciler.

The major change is we stopped relying on `len(retriesStatus)` to
decide if a target `TaskRun` failed or not. Instead, we use status
`ConditionSuceeded` to gate the completion of a `TaskRun`. Even a
`TaskRun` failed on one execution, as long as it has remaining
retries, the TaskRun won't be stored in etcd with its status set
as `Failed`. Instead, the status will be:

```yaml
Type: Succeeded
Status: Unknown
Reason: ToBeRetried
```

Author: XinruZhang

docs/taskruns.md

@@ -26,6 +26,7 @@ weight: 300
   - [Specifying `Sidecars`](#specifying-sidecars)
   - [Overriding `Task` `Steps` and `Sidecars`](#overriding-task-steps-and-sidecars)
   - [Specifying `LimitRange` values](#specifying-limitrange-values)
+  - [Specifying `Retries`](#specifying-retries)
   - [Configuring the failure timeout](#configuring-the-failure-timeout)
   - [Specifying `ServiceAccount` credentials](#specifying-serviceaccount-credentials)
 - [Monitoring execution status](#monitoring-execution-status)
@@ -698,11 +699,25 @@ object(s), if present. Any `Request` or `Limit` specified by the user (on `Task`
 
 For more information, see the [`LimitRange` support in Pipeline](./compute-resources.md#limitrange-support).
 
+### Specifying `Retries`
+You can use the `retries` field to set how many times you want to retry on a failed TaskRun.
+All TaskRun failures are retriable except for `Cancellation`.
+
+For a retriable `TaskRun`, when an error occurs:
+- The error status is archived in `status.RetriesStatus`
+- The `Succeeded` condition in `status` is updated:
+```
+Type: Succeeded
+Status: Unknown
+Reason: ToBeRetried
+```
+- `status.StartTime` and `status.PodName` are unset to trigger another retry attempt.
+
 ### Configuring the failure timeout
 
-You can use the `timeout` field to set the `TaskRun's` desired timeout value. If you do not specify this
-value for the `TaskRun`, the global default timeout value applies. If you set the timeout to 0, the `TaskRun` will
-have no timeout and will run until it completes successfully or fails from an error.
+You can use the `timeout` field to set the `TaskRun's` desired timeout value for **each retry attempt**. If you do
+not specify this value, the global default timeout value applies (the same, to `each retry attempt`). If you set the timeout to 0,
+the `TaskRun` will have no timeout and will run until it completes successfully or fails from an error.
 
 The global default timeout is set to 60 minutes when you first install Tekton. You can set
 a different global default timeout value using the `default-timeout-minutes` field in

pkg/pod/status.go

@@ -368,6 +368,16 @@ func DidTaskRunFail(pod *corev1.Pod) bool {
 	return f
 }
 
+// IsPodArchived indicates if a pod is archived in the retriesStatus.
+func IsPodArchived(pod *corev1.Pod, trs *v1beta1.TaskRunStatus) bool {
+	for _, retryStatus := range trs.RetriesStatus {
+		if retryStatus.PodName == pod.GetName() {
+			return true
+		}
+	}
+	return false
+}
+
 func areStepsComplete(pod *corev1.Pod) bool {
 	stepsComplete := len(pod.Status.ContainerStatuses) > 0 && pod.Status.Phase == corev1.PodRunning
 	for _, s := range pod.Status.ContainerStatuses {

pkg/pod/status_test.go

@@ -1634,6 +1634,51 @@ func TestMarkStatusSuccess(t *testing.T) {
 	}
 }
 
+func TestIsPodArchived(t *testing.T) {
+	for _, tc := range []struct {
+		name          string
+		podName       string
+		retriesStatus []v1beta1.TaskRunStatus
+		want          bool
+	}{{
+		name:          "Pod is not in the empty retriesStatus",
+		podName:       "pod",
+		retriesStatus: []v1beta1.TaskRunStatus{},
+		want:          false,
+	}, {
+		name:    "Pod is not in the non-empty retriesStatus",
+		podName: "pod-retry1",
+		retriesStatus: []v1beta1.TaskRunStatus{{
+			TaskRunStatusFields: v1beta1.TaskRunStatusFields{
+				PodName: "pod",
+			},
+		}},
+		want: false,
+	}, {
+		name:    "Pod is in the retriesStatus",
+		podName: "pod",
+		retriesStatus: []v1beta1.TaskRunStatus{{
+			TaskRunStatusFields: v1beta1.TaskRunStatusFields{
+				PodName: "pod",
+			}},
+		},
+		want: true,
+	}} {
+		t.Run(tc.name, func(t *testing.T) {
+			trs := v1beta1.TaskRunStatus{
+				TaskRunStatusFields: v1beta1.TaskRunStatusFields{
+					PodName:       "pod",
+					RetriesStatus: tc.retriesStatus,
+				},
+			}
+			got := IsPodArchived(&corev1.Pod{ObjectMeta: metav1.ObjectMeta{Name: tc.podName}}, &trs)
+			if tc.want != got {
+				t.Errorf("got: %v, want: %v", got, tc.want)
+			}
+		})
+	}
+}
+
 func statusRunning() duckv1.Status {
 	var trs v1beta1.TaskRunStatus
 	markStatusRunning(&trs, v1beta1.TaskRunReasonRunning.String(), "Not all Steps in the Task have finished executing")

pkg/reconciler/pipelinerun/pipelinerun.go

@@ -888,26 +888,10 @@ func (c *Reconciler) createTaskRuns(ctx context.Context, rpt *resources.Resolved
 func (c *Reconciler) createTaskRun(ctx context.Context, taskRunName string, params []v1beta1.Param, rpt *resources.ResolvedPipelineTask, pr *v1beta1.PipelineRun, storageBasePath string) (*v1beta1.TaskRun, error) {
 	logger := logging.FromContext(ctx)
 
-	tr, _ := c.taskRunLister.TaskRuns(pr.Namespace).Get(taskRunName)
-	if tr != nil {
-		// retry should happen only when the taskrun has failed
-		if !tr.Status.GetCondition(apis.ConditionSucceeded).IsFalse() {
-			return tr, nil
-		}
-		// Don't modify the lister cache's copy.
-		tr = tr.DeepCopy()
-		// is a retry
-		addRetryHistory(tr)
-		clearStatus(tr)
-		tr.Status.MarkResourceOngoing("", "")
-		logger.Infof("Updating taskrun %s with cleared status and retry history (length: %d).", tr.GetName(), len(tr.Status.RetriesStatus))
-		return c.PipelineClientSet.TektonV1beta1().TaskRuns(pr.Namespace).UpdateStatus(ctx, tr, metav1.UpdateOptions{})
-	}
-
 	rpt.PipelineTask = resources.ApplyPipelineTaskContexts(rpt.PipelineTask)
 	taskRunSpec := pr.GetTaskRunSpec(rpt.PipelineTask.Name)
 	params = append(params, rpt.PipelineTask.Params...)
-	tr = &v1beta1.TaskRun{
+	tr := &v1beta1.TaskRun{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:            taskRunName,
 			Namespace:       pr.Namespace,
@@ -916,6 +900,7 @@ func (c *Reconciler) createTaskRun(ctx context.Context, taskRunName string, para
 			Annotations:     combineTaskRunAndTaskSpecAnnotations(pr, rpt.PipelineTask),
 		},
 		Spec: v1beta1.TaskRunSpec{
+			Retries:            rpt.PipelineTask.Retries,
 			Params:             params,
 			ServiceAccountName: taskRunSpec.TaskServiceAccountName,
 			PodTemplate:        taskRunSpec.TaskPodTemplate,
@@ -1169,18 +1154,6 @@ func combinedSubPath(workspaceSubPath string, pipelineTaskSubPath string) string
 	return filepath.Join(workspaceSubPath, pipelineTaskSubPath)
 }
 
-func addRetryHistory(tr *v1beta1.TaskRun) {
-	newStatus := *tr.Status.DeepCopy()
-	newStatus.RetriesStatus = nil
-	tr.Status.RetriesStatus = append(tr.Status.RetriesStatus, newStatus)
-}
-
-func clearStatus(tr *v1beta1.TaskRun) {
-	tr.Status.StartTime = nil
-	tr.Status.CompletionTime = nil
-	tr.Status.PodName = ""
-}
-
 func getTaskrunAnnotations(pr *v1beta1.PipelineRun) map[string]string {
 	// Propagate annotations from PipelineRun to TaskRun.
 	annotations := make(map[string]string, len(pr.ObjectMeta.Annotations)+1)

pkg/reconciler/pipelinerun/pipelinerun_test.go

@@ -494,6 +494,7 @@ spec:
     value: test-pipeline
   - name: contextRetriesParam
     value: "5"
+  retries: 5
   resources:
     inputs:
     - name: workspace
@@ -3527,103 +3528,6 @@ spec:
 	}
 }
 
-// TestReconcileWithTimeoutAndRetry runs "Reconcile" against pipelines with
-// retries and timeout settings, and status that represents different number of
-// retries already performed.  It verifies the reconciled status and events
-// generated
-func TestReconcileWithTimeoutAndRetry(t *testing.T) {
-	for _, tc := range []struct {
-		name               string
-		retries            int
-		conditionSucceeded corev1.ConditionStatus
-		wantEvents         []string
-	}{{
-		name:               "One try has to be done",
-		retries:            1,
-		conditionSucceeded: corev1.ConditionFalse,
-		wantEvents: []string{
-			"Warning Failed PipelineRun \"test-pipeline-retry-run-with-timeout\" failed to finish within",
-		},
-	}, {
-		name:               "No more retries are needed",
-		retries:            2,
-		conditionSucceeded: corev1.ConditionUnknown,
-		wantEvents: []string{
-			"Warning Failed PipelineRun \"test-pipeline-retry-run-with-timeout\" failed to finish within",
-		},
-	}} {
-		t.Run(tc.name, func(t *testing.T) {
-			ps := []*v1beta1.Pipeline{parse.MustParseV1beta1Pipeline(t, fmt.Sprintf(`
-metadata:
-  name: test-pipeline-retry
-  namespace: foo
-spec:
-  tasks:
-  - name: hello-world-1
-    retries: %d
-    taskRef:
-      name: hello-world
-`, tc.retries))}
-			prs := []*v1beta1.PipelineRun{parse.MustParseV1beta1PipelineRun(t, `
-metadata:
-  name: test-pipeline-retry-run-with-timeout
-  namespace: foo
-spec:
-  pipelineRef:
-    name: test-pipeline-retry
-  serviceAccountName: test-sa
-  timeout: 12h0m0s
-status:
-  startTime: "2021-12-31T00:00:00Z"
-`)}
-
-			ts := []*v1beta1.Task{
-				simpleHelloWorldTask,
-			}
-			trs := []*v1beta1.TaskRun{parse.MustParseV1beta1TaskRun(t, `
-metadata:
-  name: hello-world-1
-  namespace: foo
-status:
-  conditions:
-  - status: "False"
-    type: Succeeded
-  podName: my-pod-name
-  retriesStatus:
-  - conditions:
-    - status: "False"
-      type: Succeeded
-`)}
-
-			prtrs := &v1beta1.PipelineRunTaskRunStatus{
-				PipelineTaskName: "hello-world-1",
-				Status:           &trs[0].Status,
-			}
-			prs[0].Status.TaskRuns = make(map[string]*v1beta1.PipelineRunTaskRunStatus)
-			prs[0].Status.TaskRuns["hello-world-1"] = prtrs
-
-			d := test.Data{
-				PipelineRuns: prs,
-				Pipelines:    ps,
-				Tasks:        ts,
-				TaskRuns:     trs,
-			}
-			prt := newPipelineRunTest(d, t)
-			defer prt.Cancel()
-
-			reconciledRun, _ := prt.reconcileRun("foo", "test-pipeline-retry-run-with-timeout", []string{}, false)
-
-			if len(reconciledRun.Status.TaskRuns["hello-world-1"].Status.RetriesStatus) != tc.retries {
-				t.Fatalf(" %d retries expected but got %d ", tc.retries, len(reconciledRun.Status.TaskRuns["hello-world-1"].Status.RetriesStatus))
-			}
-
-			if status := reconciledRun.Status.TaskRuns["hello-world-1"].Status.GetCondition(apis.ConditionSucceeded).Status; status != tc.conditionSucceeded {
-				t.Fatalf("Succeeded expected to be %s but is %s", tc.conditionSucceeded, status)
-			}
-		})
-	}
-}
-
 // TestReconcileAndPropagateCustomPipelineTaskRunSpec tests that custom PipelineTaskRunSpec declared
 // in PipelineRun is propagated to created TaskRuns
 func TestReconcileAndPropagateCustomPipelineTaskRunSpec(t *testing.T) {
@@ -9673,6 +9577,7 @@ spec:
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: linux
@@ -9687,12 +9592,17 @@ status:
   conditions:
   - type: Succeeded
     status: "False"
+  retriesStatus:
+  - conditions:
+    - status: "False"
+      type: Succeeded
 `),
 			mustParseTaskRunWithObjectMeta(t,
 				taskRunObjectMeta("pr-platforms-and-browsers-1", "foo",
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: mac
@@ -9807,6 +9717,7 @@ status:
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: linux
@@ -9820,7 +9731,7 @@ spec:
 status:
   conditions:
   - type: Succeeded
-    status: "Unknown"
+    status: "False"
   retriesStatus:
   - conditions:
     - status: "False"
@@ -9831,6 +9742,7 @@ status:
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: mac
@@ -9855,6 +9767,7 @@ status:
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: linux
@@ -9868,13 +9781,18 @@ spec:
 status:
   conditions:
   - type: Succeeded
-    status: "False"
+    status: "Unknown"
+  retriesStatus:
+  - conditions:
+    - status: "False"
+      type: Succeeded
 `),
 			mustParseTaskRunWithObjectMeta(t,
 				taskRunObjectMeta("pr-platforms-and-browsers-1", "foo",
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: mac
@@ -9888,7 +9806,11 @@ spec:
 status:
   conditions:
   - type: Succeeded
-    status: "False"
+    status: "Unknown"
+  retriesStatus:
+  - conditions:
+    - status: "False"
+      type: Succeeded
 `),
 		},
 		prs: []*v1beta1.PipelineRun{
@@ -9989,6 +9911,7 @@ status:
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: linux
@@ -10013,6 +9936,7 @@ status:
 					"pr", "p", "platforms-and-browsers", false),
 				`
 spec:
+  retries: 1
   params:
   - name: platform
     value: mac