Add back more v1beta1 util functions from v1.10.3

With v1beta2, some v1beta1 util functions have been saved in
util/deprecated/v1beta1 for consumers that still support v1beta1
objects. This patch adds more v1beta1-focused utils packages to the
deprecated/v1beta1 folder:

* util
* util/annnotations
* util/collections
* util/predicates

Author: pierreprinetti

util/deprecated/v1beta1/annotations/helpers.go

@@ -0,0 +1,142 @@
+/*
+Copyright 2020 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 annotations implements annotation helper functions.
+package annotations
+
+import (
+	"regexp"
+	"strings"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	clusterv1 "sigs.k8s.io/cluster-api/api/core/v1beta1"
+)
+
+// IsPaused returns true if the Cluster is paused or the object has the `paused` annotation.
+func IsPaused(cluster *clusterv1.Cluster, o metav1.Object) bool {
+	if cluster.Spec.Paused {
+		return true
+	}
+	return HasPaused(o)
+}
+
+// IsExternallyManaged returns true if the object has the `managed-by` annotation.
+func IsExternallyManaged(o metav1.Object) bool {
+	return hasAnnotation(o, clusterv1.ManagedByAnnotation)
+}
+
+// HasPaused returns true if the object has the `paused` annotation.
+func HasPaused(o metav1.Object) bool {
+	return hasAnnotation(o, clusterv1.PausedAnnotation)
+}
+
+// HasSkipRemediation returns true if the object has the `skip-remediation` annotation.
+func HasSkipRemediation(o metav1.Object) bool {
+	return hasAnnotation(o, clusterv1.MachineSkipRemediationAnnotation)
+}
+
+// HasRemediateMachine returns true if the object has the `remediate-machine` annotation.
+func HasRemediateMachine(o metav1.Object) bool {
+	return hasAnnotation(o, clusterv1.RemediateMachineAnnotation)
+}
+
+// HasWithPrefix returns true if at least one of the annotations has the prefix specified.
+func HasWithPrefix(prefix string, annotations map[string]string) bool {
+	for key := range annotations {
+		if strings.HasPrefix(key, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+// ReplicasManagedByExternalAutoscaler returns true if the standard annotation for external autoscaler is present.
+func ReplicasManagedByExternalAutoscaler(o metav1.Object) bool {
+	return hasTruthyAnnotationValue(o, clusterv1.ReplicasManagedByAnnotation)
+}
+
+// AddAnnotations sets the desired annotations on the object and returns true if the annotations have changed.
+func AddAnnotations(o metav1.Object, desired map[string]string) bool {
+	if len(desired) == 0 {
+		return false
+	}
+	annotations := o.GetAnnotations()
+	if annotations == nil {
+		annotations = make(map[string]string)
+	}
+	hasChanged := false
+	for k, v := range desired {
+		if cur, ok := annotations[k]; !ok || cur != v {
+			annotations[k] = v
+			hasChanged = true
+		}
+	}
+	o.SetAnnotations(annotations)
+	return hasChanged
+}
+
+// GetManagedAnnotations filters out and returns the CAPI-managed annotations for a Machine, with an optional list of regex patterns for user-specified annotations.
+func GetManagedAnnotations(m *clusterv1.Machine, additionalSyncMachineAnnotations ...*regexp.Regexp) map[string]string {
+	// Always sync CAPI's bookkeeping annotations
+	managedAnnotations := map[string]string{
+		clusterv1.ClusterNameAnnotation:      m.Spec.ClusterName,
+		clusterv1.ClusterNamespaceAnnotation: m.GetNamespace(),
+		clusterv1.MachineAnnotation:          m.Name,
+	}
+	if owner := metav1.GetControllerOfNoCopy(m); owner != nil {
+		managedAnnotations[clusterv1.OwnerKindAnnotation] = owner.Kind
+		managedAnnotations[clusterv1.OwnerNameAnnotation] = owner.Name
+	}
+	for key, value := range m.GetAnnotations() {
+		// Always sync CAPI's default annotation node domain
+		dnsSubdomainOrName := strings.Split(key, "/")[0]
+		if dnsSubdomainOrName == clusterv1.ManagedNodeAnnotationDomain || strings.HasSuffix(dnsSubdomainOrName, "."+clusterv1.ManagedNodeAnnotationDomain) {
+			managedAnnotations[key] = value
+			continue
+		}
+		// Sync if the annotations matches at least one user provided regex
+		for _, regex := range additionalSyncMachineAnnotations {
+			if regex.MatchString(key) {
+				managedAnnotations[key] = value
+				break
+			}
+		}
+	}
+	return managedAnnotations
+}
+
+// hasAnnotation returns true if the object has the specified annotation.
+func hasAnnotation(o metav1.Object, annotation string) bool {
+	annotations := o.GetAnnotations()
+	if annotations == nil {
+		return false
+	}
+	_, ok := annotations[annotation]
+	return ok
+}
+
+// hasTruthyAnnotationValue returns true if the object has an annotation with a value that is not "false".
+func hasTruthyAnnotationValue(o metav1.Object, annotation string) bool {
+	annotations := o.GetAnnotations()
+	if annotations == nil {
+		return false
+	}
+	if val, ok := annotations[annotation]; ok {
+		return val != "false"
+	}
+	return false
+}