1 files changed, 178 insertions, 0 deletions
diff --git a/src/k8splugin/internal/utils/deploymentutil.go b/src/k8splugin/internal/utils/deploymentutil.go
new file mode 100644
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+++ b/src/k8splugin/internal/utils/deploymentutil.go
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+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"context"
+	"sort"
+
+	apps "k8s.io/api/apps/v1"
+	v1 "k8s.io/api/core/v1"
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	intstrutil "k8s.io/apimachinery/pkg/util/intstr"
+	appsclient "k8s.io/client-go/kubernetes/typed/apps/v1"
+)
+
+// deploymentutil contains a copy of a few functions from Kubernetes controller code to avoid a dependency on k8s.io/kubernetes.
+// This code is copied from https://github.com/kubernetes/kubernetes/blob/e856613dd5bb00bcfaca6974431151b5c06cbed5/pkg/controller/deployment/util/deployment_util.go
+// No changes to the code were made other than removing some unused functions
+
+// RsListFunc returns the ReplicaSet from the ReplicaSet namespace and the List metav1.ListOptions.
+type RsListFunc func(string, metav1.ListOptions) ([]*apps.ReplicaSet, error)
+
+// ListReplicaSets returns a slice of RSes the given deployment targets.
+// Note that this does NOT attempt to reconcile ControllerRef (adopt/orphan),
+// because only the controller itself should do that.
+// However, it does filter out anything whose ControllerRef doesn't match.
+func ListReplicaSets(deployment *apps.Deployment, getRSList RsListFunc) ([]*apps.ReplicaSet, error) {
+	// TODO: Right now we list replica sets by their labels. We should list them by selector, i.e. the replica set's selector
+	//       should be a superset of the deployment's selector, see https://github.com/kubernetes/kubernetes/issues/19830.
+	namespace := deployment.Namespace
+	selector, err := metav1.LabelSelectorAsSelector(deployment.Spec.Selector)
+	if err != nil {
+		return nil, err
+	}
+	options := metav1.ListOptions{LabelSelector: selector.String()}
+	all, err := getRSList(namespace, options)
+	if err != nil {
+		return nil, err
+	}
+	// Only include those whose ControllerRef matches the Deployment.
+	owned := make([]*apps.ReplicaSet, 0, len(all))
+	for _, rs := range all {
+		if metav1.IsControlledBy(rs, deployment) {
+			owned = append(owned, rs)
+		}
+	}
+	return owned, nil
+}
+
+// ReplicaSetsByCreationTimestamp sorts a list of ReplicaSet by creation timestamp, using their names as a tie breaker.
+type ReplicaSetsByCreationTimestamp []*apps.ReplicaSet
+
+func (o ReplicaSetsByCreationTimestamp) Len() int      { return len(o) }
+func (o ReplicaSetsByCreationTimestamp) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
+func (o ReplicaSetsByCreationTimestamp) Less(i, j int) bool {
+	if o[i].CreationTimestamp.Equal(&o[j].CreationTimestamp) {
+		return o[i].Name < o[j].Name
+	}
+	return o[i].CreationTimestamp.Before(&o[j].CreationTimestamp)
+}
+
+// FindNewReplicaSet returns the new RS this given deployment targets (the one with the same pod template).
+func FindNewReplicaSet(deployment *apps.Deployment, rsList []*apps.ReplicaSet) *apps.ReplicaSet {
+	sort.Sort(ReplicaSetsByCreationTimestamp(rsList))
+	for i := range rsList {
+		if EqualIgnoreHash(&rsList[i].Spec.Template, &deployment.Spec.Template) {
+			// In rare cases, such as after cluster upgrades, Deployment may end up with
+			// having more than one new ReplicaSets that have the same template as its template,
+			// see https://github.com/kubernetes/kubernetes/issues/40415
+			// We deterministically choose the oldest new ReplicaSet.
+			return rsList[i]
+		}
+	}
+	// new ReplicaSet does not exist.
+	return nil
+}
+
+// EqualIgnoreHash returns true if two given podTemplateSpec are equal, ignoring the diff in value of Labels[pod-template-hash]
+// We ignore pod-template-hash because:
+// 1. The hash result would be different upon podTemplateSpec API changes
+//    (e.g. the addition of a new field will cause the hash code to change)
+// 2. The deployment template won't have hash labels
+func EqualIgnoreHash(template1, template2 *v1.PodTemplateSpec) bool {
+	t1Copy := template1.DeepCopy()
+	t2Copy := template2.DeepCopy()
+	// Remove hash labels from template.Labels before comparing
+	delete(t1Copy.Labels, apps.DefaultDeploymentUniqueLabelKey)
+	delete(t2Copy.Labels, apps.DefaultDeploymentUniqueLabelKey)
+	return apiequality.Semantic.DeepEqual(t1Copy, t2Copy)
+}
+
+// GetNewReplicaSet returns a replica set that matches the intent of the given deployment; get ReplicaSetList from client interface.
+// Returns nil if the new replica set doesn't exist yet.
+func GetNewReplicaSet(deployment *apps.Deployment, c appsclient.AppsV1Interface) (*apps.ReplicaSet, error) {
+	rsList, err := ListReplicaSets(deployment, RsListFromClient(c))
+	if err != nil {
+		return nil, err
+	}
+	return FindNewReplicaSet(deployment, rsList), nil
+}
+
+// RsListFromClient returns an rsListFunc that wraps the given client.
+func RsListFromClient(c appsclient.AppsV1Interface) RsListFunc {
+	return func(namespace string, options metav1.ListOptions) ([]*apps.ReplicaSet, error) {
+		rsList, err := c.ReplicaSets(namespace).List(context.Background(), options)
+		if err != nil {
+			return nil, err
+		}
+		var ret []*apps.ReplicaSet
+		for i := range rsList.Items {
+			ret = append(ret, &rsList.Items[i])
+		}
+		return ret, err
+	}
+}
+
+// IsRollingUpdate returns true if the strategy type is a rolling update.
+func IsRollingUpdate(deployment *apps.Deployment) bool {
+	return deployment.Spec.Strategy.Type == apps.RollingUpdateDeploymentStrategyType
+}
+
+// MaxUnavailable returns the maximum unavailable pods a rolling deployment can take.
+func MaxUnavailable(deployment apps.Deployment) int32 {
+	if !IsRollingUpdate(&deployment) || *(deployment.Spec.Replicas) == 0 {
+		return int32(0)
+	}
+	// Error caught by validation
+	_, maxUnavailable, _ := ResolveFenceposts(deployment.Spec.Strategy.RollingUpdate.MaxSurge, deployment.Spec.Strategy.RollingUpdate.MaxUnavailable, *(deployment.Spec.Replicas))
+	if maxUnavailable > *deployment.Spec.Replicas {
+		return *deployment.Spec.Replicas
+	}
+	return maxUnavailable
+}
+
+// ResolveFenceposts resolves both maxSurge and maxUnavailable. This needs to happen in one
+// step. For example:
+//
+// 2 desired, max unavailable 1%, surge 0% - should scale old(-1), then new(+1), then old(-1), then new(+1)
+// 1 desired, max unavailable 1%, surge 0% - should scale old(-1), then new(+1)
+// 2 desired, max unavailable 25%, surge 1% - should scale new(+1), then old(-1), then new(+1), then old(-1)
+// 1 desired, max unavailable 25%, surge 1% - should scale new(+1), then old(-1)
+// 2 desired, max unavailable 0%, surge 1% - should scale new(+1), then old(-1), then new(+1), then old(-1)
+// 1 desired, max unavailable 0%, surge 1% - should scale new(+1), then old(-1)
+func ResolveFenceposts(maxSurge, maxUnavailable *intstrutil.IntOrString, desired int32) (int32, int32, error) {
+	surge, err := intstrutil.GetValueFromIntOrPercent(intstrutil.ValueOrDefault(maxSurge, intstrutil.FromInt(0)), int(desired), true)
+	if err != nil {
+		return 0, 0, err
+	}
+	unavailable, err := intstrutil.GetValueFromIntOrPercent(intstrutil.ValueOrDefault(maxUnavailable, intstrutil.FromInt(0)), int(desired), false)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	if surge == 0 && unavailable == 0 {
+		// Validation should never allow the user to explicitly use zero values for both maxSurge
+		// maxUnavailable. Due to rounding down maxUnavailable though, it may resolve to zero.
+		// If both fenceposts resolve to zero, then we should set maxUnavailable to 1 on the
+		// theory that surge might not work due to quota.
+		unavailable = 1
+	}
+
+	return int32(surge), int32(unavailable), nil
+}