feature: introduce rollback windows

fixes: argoproj#574
Signed-off-by: Alex Eftimie <[email protected]>

pkg/apis/rollouts/v1alpha1/types.go

@@ -56,6 +56,9 @@ type RolloutSpec struct {
 	// Defaults to 0 (pod will be considered available as soon as it is ready)
 	// +optional
 	MinReadySeconds int32 `json:"minReadySeconds,omitempty" protobuf:"varint,4,opt,name=minReadySeconds"`
+	// The window in which a rollback will be fast tracked (fully promoted)
+	// +optional
+	RollbackWindow *RollbackWindowSpec `json:"rollbackWindow,omtempty" protobuf:"bytes,13,opt,name=rollbackWindow"`
 	// The deployment strategy to use to replace existing pods with new ones.
 	// +optional
 	Strategy RolloutStrategy `json:"strategy" protobuf:"bytes,5,opt,name=strategy"`
@@ -1021,3 +1024,7 @@ type RolloutList struct {
 
 	Items []Rollout `json:"items" protobuf:"bytes,2,rep,name=items"`
 }
+
+type RollbackWindowSpec struct {
+	Revisions int32 `json:"revisions,omitempty" protobuf:"varint,1,opt,name=revisions"`
+}

rollout/sync.go

@@ -857,6 +857,31 @@ func (c *rolloutContext) resetRolloutStatus(newStatus *v1alpha1.RolloutStatus) {
 	newStatus.CurrentStepIndex = replicasetutil.ResetCurrentStepIndex(c.rollout)
 }
 
+func (c *rolloutContext) isRollbackWithinWindow() bool {
+	if c.newRS == nil || c.stableRS == nil {
+		return false
+	}
+	// first check if this is a rollback
+	if c.newRS.CreationTimestamp.Before(&c.stableRS.CreationTimestamp) {
+		// then check if we are within window
+		if c.rollout.Spec.RollbackWindow != nil {
+			if c.rollout.Spec.RollbackWindow.Revisions > 0 {
+				var windowSize int32
+				for _, rs := range c.allRSs {
+					if rs.CreationTimestamp.Before(&c.stableRS.CreationTimestamp) &&
+						c.stableRS.CreationTimestamp.Before(&rs.CreationTimestamp) {
+						windowSize = windowSize + 1
+					}
+				}
+				if windowSize <= c.rollout.Spec.RollbackWindow.Revisions {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
 // shouldFullPromote returns a reason string explaining why a rollout should fully promote, marking
 // the desired ReplicaSet as stable. Returns empty string if the rollout is in middle of update
 func (c *rolloutContext) shouldFullPromote(newStatus v1alpha1.RolloutStatus) string {
@@ -873,6 +898,9 @@ func (c *rolloutContext) shouldFullPromote(newStatus v1alpha1.RolloutStatus) str
 		if c.rollout.Status.PromoteFull {
 			return "Full promotion requested"
 		}
+		if c.isRollbackWithinWindow() {
+			return "Rollback within window"
+		}
 		_, currentStepIndex := replicasetutil.GetCurrentCanaryStep(c.rollout)
 		stepCount := len(c.rollout.Spec.Strategy.Canary.Steps)
 		completedAllSteps := stepCount == 0 || (currentStepIndex != nil && *currentStepIndex == int32(stepCount))
@@ -897,6 +925,9 @@ func (c *rolloutContext) shouldFullPromote(newStatus v1alpha1.RolloutStatus) str
 		if c.rollout.Status.PromoteFull {
 			return "Full promotion requested"
 		}
+		if c.isRollbackWithinWindow() {
+			return "Rollback within window"
+		}
 		if c.pauseContext.IsAborted() {
 			return ""
 		}

rollout/sync_test.go

@@ -453,3 +453,61 @@ func TestSendStateChangeEvents(t *testing.T) {
 		assert.Equal(t, test.expectedEventReasons, recorder.Events)
 	}
 }
+
+// TestRollbackWindow verifies the rollback window conditions
+func TestRollbackWindow(t *testing.T) {
+	now := timeutil.MetaNow()
+	before := metav1.Time{Time: now.Add(-time.Minute)}
+
+	replicaSets := []*appsv1.ReplicaSet{
+		{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:              "foo",
+				CreationTimestamp: before,
+			},
+		},
+		{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:              "foo-1",
+				CreationTimestamp: now,
+			},
+		},
+	}
+	// FIXME: parametrize this
+	ctx := &rolloutContext{
+		allRSs:   replicaSets,
+		newRS:    replicaSets[0],
+		stableRS: replicaSets[1],
+	}
+	ctx.rollout = &v1alpha1.Rollout{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "foo",
+			Namespace: "default",
+		},
+		Spec: v1alpha1.RolloutSpec{
+			RollbackWindow: &v1alpha1.RollbackWindowSpec{
+				Revisions: 1,
+			},
+		},
+	}
+	assert.True(t, ctx.isRollbackWithinWindow())
+
+	ctx = &rolloutContext{
+		allRSs:   replicaSets,
+		newRS:    replicaSets[1],
+		stableRS: replicaSets[0],
+	}
+	ctx.rollout = &v1alpha1.Rollout{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "foo",
+			Namespace: "default",
+		},
+		Spec: v1alpha1.RolloutSpec{
+			RollbackWindow: &v1alpha1.RollbackWindowSpec{
+				Revisions: 1,
+			},
+		},
+	}
+
+	assert.False(t, ctx.isRollbackWithinWindow())
+}