Add a generic Walk()'er to list a bucket, optinally prefix (#9026)

This generic Walk() is used by likes of Lifecyle, or
KMS to rotate keys or any other functionality which
relies on this functionality.

pkg/bucket/lifecycle/lifecycle.go

@@ -99,8 +99,11 @@ func (lc Lifecycle) Validate() error {
 // FilterRuleActions returns the expiration and transition from the object name
 // after evaluating all rules.
 func (lc Lifecycle) FilterRuleActions(objName, objTags string) (Expiration, Transition) {
+	if objName == "" {
+		return Expiration{}, Transition{}
+	}
 	for _, rule := range lc.Rules {
-		if strings.ToLower(rule.Status) != "enabled" {
+		if rule.Status == Disabled {
 			continue
 		}
 		tags := rule.Tags()
@@ -121,6 +124,9 @@ func (lc Lifecycle) FilterRuleActions(objName, objTags string) (Expiration, Tran
 // against the object name and its modification time.
 func (lc Lifecycle) ComputeAction(objName, objTags string, modTime time.Time) Action {
 	var action = NoneAction
+	if modTime.IsZero() {
+		return action
+	}
 	exp, _ := lc.FilterRuleActions(objName, objTags)
 	if !exp.IsDateNull() {
 		if time.Now().After(exp.Date.Time) {

pkg/bucket/lifecycle/lifecycle_test.go

@@ -179,6 +179,12 @@ func TestComputeActions(t *testing.T) {
 			objectModTime:  time.Now().UTC().Add(-10 * 24 * time.Hour), // Created 10 days ago
 			expectedAction: NoneAction,
 		},
+		// No modTime, should be none-action
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			expectedAction: NoneAction,
+		},
 		// Prefix not matched
 		{
 			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,

pkg/bucket/lifecycle/rule.go

@@ -21,11 +21,20 @@ import (
 	"encoding/xml"
 )
 
+// Status represents lifecycle configuration status
+type Status string
+
+// Supported status types
+const (
+	Enabled  Status = "Enabled"
+	Disabled Status = "Disabled"
+)
+
 // Rule - a rule for lifecycle configuration.
 type Rule struct {
 	XMLName    xml.Name   `xml:"Rule"`
 	ID         string     `xml:"ID,omitempty"`
-	Status     string     `xml:"Status"`
+	Status     Status     `xml:"Status"`
 	Filter     Filter     `xml:"Filter,omitempty"`
 	Expiration Expiration `xml:"Expiration,omitempty"`
 	Transition Transition `xml:"Transition,omitempty"`
@@ -58,7 +67,7 @@ func (r Rule) validateStatus() error {
 	}
 
 	// Status must be one of Enabled or Disabled
-	if r.Status != "Enabled" && r.Status != "Disabled" {
+	if r.Status != Enabled && r.Status != Disabled {
 		return errInvalidRuleStatus
 	}
 	return nil