Library for computing status for Kubernetes resources

kstatus/status/generic.go

@@ -0,0 +1,92 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package status
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+	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
+// all or most of the Kubernetes resources. If a decision can be made based
+// on this information, there is no need to look at the resource-specidic
+// rules.
+// This also checks for the presence of the conditions defined in this package.
+// If any of these are set on the resource, a decision is made solely based
+// on this and none of the resource specific rules will be used. The goal here
+// is that if controllers, built-in or custom, use these conditions, we can easily
+// find status of resources.
+func checkGenericProperties(u *unstructured.Unstructured) (*Result, error) {
+	obj := u.UnstructuredContent()
+
+	// Check if the resource is scheduled for deletion
+	deletionTimestamp, found, err := unstructured.NestedString(obj, "metadata", "deletionTimestamp")
+	if err != nil {
+		return nil, errors.Wrap(err, "looking up metadata.deletionTimestamp from resource")
+	}
+	if found && deletionTimestamp != "" {
+		return &Result{
+			Status:     TerminatingStatus,
+			Message:    "Resource scheduled for deletion",
+			Conditions: []Condition{},
+		}, nil
+	}
+
+	// ensure that the meta generation is observed
+	generation, found, err := unstructured.NestedInt64(u.Object, "metadata", "generation")
+	if err != nil {
+		return nil, errors.Wrap(err, "looking up metadata.generation from resource")
+	}
+	if !found {
+		return nil, errors.New("unable to find metadata.generation from resource")
+	}
+	observedGeneration, found, err := unstructured.NestedInt64(u.Object, "status", "observedGeneration")
+	if err != nil {
+		return nil, errors.Wrap(err, "looking up status.observedGeneration from resource")
+	}
+	if found {
+		// Resource does not have this field, so we can't do this check.
+		// TODO(mortent): Verify behavior of not set vs does not exist.
+		if observedGeneration != generation {
+			message := fmt.Sprintf("%s generation is %d, but latest observed generation is %d", u.GetKind(), generation, observedGeneration)
+			return &Result{
+				Status:     InProgressStatus,
+				Message:    message,
+				Conditions: []Condition{newInProgressCondition("LatestGenerationNotObserved", message)},
+			}, nil
+		}
+	}
+
+	// Check if the resource has any of the standard conditions. If so, we just use them
+	// and no need to look at anything else.
+	objWithConditions, err := GetObjectWithConditions(obj)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, cond := range objWithConditions.Status.Conditions {
+		if cond.Type == string(ConditionInProgress) && cond.Status == corev1.ConditionTrue {
+			return newInProgressStatus(cond.Reason, cond.Message), nil
+		}
+		if cond.Type == string(ConditionFailed) && cond.Status == corev1.ConditionTrue {
+			return &Result{
+				Status:  FailedStatus,
+				Message: cond.Message,
+				Conditions: []Condition{
+					{
+						Type:    ConditionFailed,
+						Status:  corev1.ConditionTrue,
+						Reason:  cond.Reason,
+						Message: cond.Message,
+					},
+				},
+			}, nil
+		}
+	}
+
+	return nil, nil
+}