Add APIs for computing status based on fetching resource info from a

cluster

kstatus/status/core.go

@@ -6,8 +6,8 @@ package status
 import (
 	"fmt"
 
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	corev1 "sigs.k8s.io/kustomize/pseudo/k8s/api/core/v1"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
 )
 
 // GetConditionsFn defines the signature for functions to compute the
@@ -36,6 +36,8 @@ const (
 	tooFewAvailable = "LessAvailable"
 	tooFewUpdated   = "LessUpdated"
 	tooFewReplicas  = "LessReplicas"
+
+	onDeleteUpdateStrategy = "OnDelete"
 )
 
 // GetLegacyConditionsFn returns a function that can compute the status for the
@@ -71,7 +73,7 @@ func stsConditions(u *unstructured.Unstructured) (*Result, error) {
 
 	// updateStrategy==ondelete is a user managed statefulset.
 	updateStrategy := GetStringField(obj, ".spec.updateStrategy.type", "")
-	if updateStrategy == "ondelete" {
+	if updateStrategy == onDeleteUpdateStrategy {
 		return &Result{
 			Status:     CurrentStatus,
 			Message:    "StatefulSet is using the ondelete update strategy",

kstatus/status/doc.go

@@ -14,7 +14,7 @@
 // Computing the status of a resources can be done by calling the
 // Compute function in the status package.
 // import (
-//     "sigs.k8s.io/kustomize/kstatus/status
+//     "sigs.k8s.io/kustomize/kstatus/status"
 // )
 // res, err := status.Compute(resource)
 //

kstatus/status/example_test.go

@@ -7,8 +7,8 @@ import (
 	"fmt"
 	"log"
 
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	. "sigs.k8s.io/kustomize/kstatus/status"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
 	"sigs.k8s.io/yaml"
 )
 

kstatus/status/generic.go

@@ -7,8 +7,8 @@ import (
 	"fmt"
 
 	"github.com/pkg/errors"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	corev1 "sigs.k8s.io/kustomize/pseudo/k8s/api/core/v1"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
 )
 
 // checkGenericProperties looks at the properties that are available on

kstatus/status/status.go

@@ -7,8 +7,8 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	corev1 "sigs.k8s.io/kustomize/pseudo/k8s/api/core/v1"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
 )
 
 const (
@@ -23,6 +23,7 @@ const (
 	FailedStatus      Status = "Failed"
 	CurrentStatus     Status = "Current"
 	TerminatingStatus Status = "Terminating"
+	UnknownStatus     Status = "Unknown"
 )
 
 // ConditionType defines the set of condition types allowed inside a Condition struct.
@@ -81,8 +82,15 @@ type Condition struct {
 // a list of standard resources that would belong on the given resource.
 func Compute(u *unstructured.Unstructured) (*Result, error) {
 	res, err := checkGenericProperties(u)
-	if err != nil || res != nil {
-		return res, err
+	if err != nil {
+		return nil, err
+	}
+
+	// If res is not nil, it means the generic checks was able to determine
+	// the status of the resource. We don't need to check the type-specific
+	// rules.
+	if res != nil {
+		return res, nil
 	}
 
 	fn := GetLegacyConditionsFn(u)

kstatus/status/status_augment_test.go

@@ -8,8 +8,8 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	corev1 "sigs.k8s.io/kustomize/pseudo/k8s/api/core/v1"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
 )
 
 var pod = `

kstatus/status/status_compute_test.go

@@ -8,8 +8,8 @@ import (
 
 	"github.com/ghodss/yaml"
 	"github.com/stretchr/testify/assert"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	corev1 "sigs.k8s.io/kustomize/pseudo/k8s/api/core/v1"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
 )
 
 func y2u(t *testing.T, spec string) *unstructured.Unstructured {

kstatus/status/util.go

@@ -6,9 +6,9 @@ package status
 import (
 	"strings"
 
+	apiunstructured "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
 	corev1 "sigs.k8s.io/kustomize/pseudo/k8s/api/core/v1"
-	apiunstructured "sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/apis/meta/v1/unstructured"
-	"sigs.k8s.io/kustomize/pseudo/k8s/apimachinery/pkg/runtime"
 )
 
 // newInProgressCondition creates an inProgress condition with the given