Library for computing status for Kubernetes resources

kstatus/status/status.go

@@ -0,0 +1,161 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package status
+
+import (
+	"time"
+
+	"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"
+)
+
+const (
+	// The set of standard conditions defined in this package. These follow the "abnormality-true"
+	// convention where conditions should have a true value for abnormal/error situations and the absence
+	// of a condition should be interpreted as a false value, i.e. everything is normal.
+	ConditionFailed     ConditionType = "Failed"
+	ConditionInProgress ConditionType = "InProgress"
+
+	// The set of status conditions which can be assigned to resources.
+	InProgressStatus  Status = "InProgress"
+	FailedStatus      Status = "Failed"
+	CurrentStatus     Status = "Current"
+	TerminatingStatus Status = "Terminating"
+)
+
+// ConditionType defines the set of condition types allowed inside a Condition struct.
+type ConditionType string
+
+// String returns the ConditionType as a string.
+func (c ConditionType) String() string {
+	return string(c)
+}
+
+// Status defines the set of statuses a resource can have.
+type Status string
+
+// String returns the status as a string.
+func (s Status) String() string {
+	return string(s)
+}
+
+// Result contains the results of a call to compute the status of
+// a resource.
+type Result struct {
+	//Status
+	Status Status
+	// Message
+	Message string
+	// Conditions list of extracted conditions from Resource
+	Conditions []Condition
+}
+
+// Condition defines the general format for conditions on Kubernetes resources.
+// In practice, each kubernetes resource defines their own format for conditions, but
+// most (maybe all) follows this structure.
+type Condition struct {
+	// Type condition type
+	Type ConditionType
+	// Status String that describes the condition status
+	Status corev1.ConditionStatus
+	// Reason one work CamelCase reason
+	Reason string
+	// Message Human readable reason string
+	Message string
+}
+
+// Compute finds the status of a given unstructured resource. It does not
+// fetch the state of the resource from a cluster, so the provided unstructured
+// must have the complete state, including status.
+//
+// The returned result contains the status of the resource, which will be
+// one of
+//  * InProgress
+//  * Current
+//  * Failed
+//  * Terminating
+// It also contains a message that provides more information on why
+// the resource has the given status. Finally, the result also contains
+// 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
+	}
+
+	fn := GetLegacyConditionsFn(u)
+	if fn != nil {
+		return fn(u)
+	}
+
+	// The resource is not one of the built-in types with specific
+	// rules and we were unable to make a decision based on the
+	// generic rules. In this case we assume that the absence of any known
+	// conditions means the resource is current.
+	return &Result{
+		Status:     CurrentStatus,
+		Message:    "Resource is current",
+		Conditions: []Condition{},
+	}, err
+}
+
+// Augment takes a resource and augments the resource with the
+// standard status conditions.
+func Augment(u *unstructured.Unstructured) error {
+	res, err := Compute(u)
+	if err != nil {
+		return err
+	}
+
+	conditions, found, err := unstructured.NestedSlice(u.Object, "status", "conditions")
+	if err != nil {
+		return err
+	}
+
+	if !found {
+		conditions = make([]interface{}, 0)
+	}
+
+	currentTime := time.Now().UTC().Format(time.RFC3339)
+
+	for _, resCondition := range res.Conditions {
+		present := false
+		for _, c := range conditions {
+			condition, ok := c.(map[string]interface{})
+			if !ok {
+				return errors.New("condition does not have the expected structure")
+			}
+			conditionType, ok := condition["type"].(string)
+			if !ok {
+				return errors.New("condition type does not have the expected type")
+			}
+			if conditionType == string(resCondition.Type) {
+				conditionStatus, ok := condition["status"].(string)
+				if !ok {
+					return errors.New("condition status does not have the expected type")
+				}
+				if conditionStatus != string(resCondition.Status) {
+					condition["lastTransitionTime"] = currentTime
+				}
+				condition["status"] = string(resCondition.Status)
+				condition["lastUpdateTime"] = currentTime
+				condition["reason"] = resCondition.Reason
+				condition["message"] = resCondition.Message
+				present = true
+			}
+		}
+		if !present {
+			conditions = append(conditions, map[string]interface{}{
+				"lastTransitionTime": currentTime,
+				"lastUpdateTime":     currentTime,
+				"message":            resCondition.Message,
+				"reason":             resCondition.Reason,
+				"status":             string(resCondition.Status),
+				"type":               string(resCondition.Type),
+			})
+		}
+	}
+	return unstructured.SetNestedSlice(u.Object, conditions, "status", "conditions")
+}