Set limit on length of Status.Conditions of a csv

Set a maximum length of Status.Conditions of ClusterServiceVersion
object(s). The oldest condition(s) should be removed from the list
as it grows over time to keep it at limit.

The default limit is set to 20.

Jira: https://jira.coreos.com/browse/OLM-963

Author: tkashem

pkg/api/apis/operators/v1alpha1/clusterserviceversion.go

@@ -10,6 +10,11 @@ import (
 
 const (
 	CopiedLabelKey = "olm.copiedFrom"
+
+	// ConditionsLengthLimit is the maximum length of Status.Conditions of a
+	// given ClusterServiceVersion object. The oldest condition(s) are removed
+	// from the list as it grows over time to keep it at limit.
+	ConditionsLengthLimit = 20
 )
 
 // obsoleteReasons are the set of reasons that mean a CSV should no longer be processed as active
@@ -67,6 +72,18 @@ func (c *ClusterServiceVersion) SetPhaseWithEvent(phase ClusterServiceVersionPha
 
 // SetPhase sets the current phase and adds a condition if necessary
 func (c *ClusterServiceVersion) SetPhase(phase ClusterServiceVersionPhase, reason ConditionReason, message string, now metav1.Time) {
+	newCondition := func() ClusterServiceVersionCondition {
+		return ClusterServiceVersionCondition{
+			Phase:              c.Status.Phase,
+			LastTransitionTime: c.Status.LastTransitionTime,
+			LastUpdateTime:     c.Status.LastUpdateTime,
+			Message:            message,
+			Reason:             reason,
+		}
+	}
+
+	defer c.TrimConditionsIfLimitExceeded()
+
 	c.Status.LastUpdateTime = now
 	if c.Status.Phase != phase {
 		c.Status.Phase = phase
@@ -75,23 +92,13 @@ func (c *ClusterServiceVersion) SetPhase(phase ClusterServiceVersionPhase, reaso
 	c.Status.Message = message
 	c.Status.Reason = reason
 	if len(c.Status.Conditions) == 0 {
-		c.Status.Conditions = append(c.Status.Conditions, ClusterServiceVersionCondition{
-			Phase:              c.Status.Phase,
-			LastTransitionTime: c.Status.LastTransitionTime,
-			LastUpdateTime:     c.Status.LastUpdateTime,
-			Message:            message,
-			Reason:             reason,
-		})
+		c.Status.Conditions = append(c.Status.Conditions, newCondition())
+		return
 	}
+
 	previousCondition := c.Status.Conditions[len(c.Status.Conditions)-1]
 	if previousCondition.Phase != c.Status.Phase || previousCondition.Reason != c.Status.Reason {
-		c.Status.Conditions = append(c.Status.Conditions, ClusterServiceVersionCondition{
-			Phase:              c.Status.Phase,
-			LastTransitionTime: c.Status.LastTransitionTime,
-			LastUpdateTime:     c.Status.LastUpdateTime,
-			Message:            message,
-			Reason:             reason,
-		})
+		c.Status.Conditions = append(c.Status.Conditions, newCondition())
 	}
 }
 
@@ -190,3 +197,12 @@ func (set InstallModeSet) Supports(operatorNamespace string, namespaces []string
 
 	return nil
 }
+
+func (c *ClusterServiceVersion) TrimConditionsIfLimitExceeded() {
+	if len(c.Status.Conditions) <= ConditionsLengthLimit {
+		return
+	}
+
+	firstIndex := len(c.Status.Conditions) - ConditionsLengthLimit
+	c.Status.Conditions = c.Status.Conditions[firstIndex:len(c.Status.Conditions)]
+}

pkg/api/apis/operators/v1alpha1/clusterserviceversion_test.go

@@ -4,9 +4,11 @@ import (
 	"fmt"
 	"testing"
 
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	corev1 "k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
 func TestSetRequirementStatus(t *testing.T) {
@@ -282,3 +284,93 @@ func TestSupports(t *testing.T) {
 		})
 	}
 }
+
+func TestSetPhaseWithConditions(t *testing.T) {
+	tests := []struct {
+		description   string
+		limit         int
+		currentLength int
+		startIndex    int
+	}{
+		{
+			// The original list is already at limit (length == limit).
+			// We expect the oldest element ( item at 0 index) to be removed.
+			description:   "TestSetPhaseWithConditionsLengthAtLimit",
+			limit:         ConditionsLengthLimit,
+			currentLength: ConditionsLengthLimit,
+
+			// The first element from the original list should be dropped from
+			// the new list.
+			startIndex: 1,
+		},
+		{
+			// The original list is 1 length away from limit.
+			// We don't expect the list to be trimmed.
+			description:   "TestSetPhaseWithConditionsLengthBelowLimit",
+			limit:         ConditionsLengthLimit,
+			currentLength: ConditionsLengthLimit - 1,
+
+			// Everything in the original list should be preserved.
+			startIndex: 0,
+		},
+		{
+			// The original list has N more element(s) than allowed limit.
+			// We expect (N + 1) oldest elements to be deleted to keep the list
+			// at limit.
+			description:   "TestSetPhaseWithConditionsLimitExceeded",
+			limit:         ConditionsLengthLimit,
+			currentLength: ConditionsLengthLimit + 10,
+
+			// The first 11 (N=10 plus 1 to make room for the newly added
+			// condition) elements from the original list should be dropped.
+			startIndex: 11,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			csv := ClusterServiceVersion{}
+			csv.Status.Conditions = helperNewConditions(tt.currentLength)
+
+			now := metav1.Now()
+
+			oldConditionsWant := csv.Status.Conditions[tt.startIndex:]
+			lastAddedConditionWant := ClusterServiceVersionCondition{
+				Phase:              ClusterServiceVersionPhase("Pending"),
+				LastTransitionTime: now,
+				LastUpdateTime:     now,
+				Message:            "message",
+				Reason:             ConditionReason("reason"),
+			}
+
+			csv.SetPhase("Pending", "reason", "message", now)
+
+			conditionsGot := csv.Status.Conditions
+			assert.Equal(t, tt.limit, len(conditionsGot))
+
+			oldConditionsGot := conditionsGot[0 : len(conditionsGot)-1]
+			assert.EqualValues(t, oldConditionsWant, oldConditionsGot)
+
+			lastAddedConditionGot := conditionsGot[len(conditionsGot)-1]
+			assert.Equal(t, lastAddedConditionWant, lastAddedConditionGot)
+		})
+	}
+}
+
+func helperNewConditions(count int) []ClusterServiceVersionCondition {
+	conditions := make([]ClusterServiceVersionCondition, 0)
+
+	for i := 1; i <= count; i++ {
+		now := metav1.Now()
+		condition := ClusterServiceVersionCondition{
+			Phase:              ClusterServiceVersionPhase(fmt.Sprintf("phase-%d", i)),
+			LastTransitionTime: now,
+			LastUpdateTime:     now,
+			Message:            fmt.Sprintf("message-%d", i),
+			Reason:             ConditionReason(fmt.Sprintf("reason-%d", i)),
+		}
+		conditions = append(conditions, condition)
+	}
+
+	return conditions
+}