sotw: rlp workflow

Signed-off-by: Guilherme Cassolato <guicassolato@gmail.com>

api/v1/merge_strategies.go

@@ -0,0 +1,220 @@
+/*
+Copyright 2024.
+
+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 v1
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/samber/lo"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/utils/ptr"
+
+	"github.com/kuadrant/policy-machinery/machinery"
+)
+
+const (
+	AtomicMergeStrategy     = "atomic"
+	PolicyRuleMergeStrategy = "merge"
+)
+
+type MergeableRule struct {
+	Spec   any
+	Source string
+}
+
+// +kubebuilder:object:generate=false
+type MergeablePolicy interface {
+	machinery.Policy
+
+	Rules() map[string]MergeableRule
+	SetRules(map[string]MergeableRule)
+	Empty() bool
+
+	DeepCopyObject() runtime.Object
+}
+
+type SortablePolicy interface {
+	machinery.Policy
+	GetCreationTimestamp() metav1.Time
+}
+
+type PolicyByCreationTimestamp []SortablePolicy
+
+func (a PolicyByCreationTimestamp) Len() int      { return len(a) }
+func (a PolicyByCreationTimestamp) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+func (a PolicyByCreationTimestamp) Less(i, j int) bool {
+	p1Time := ptr.To(a[i].GetCreationTimestamp())
+	p2Time := ptr.To(a[j].GetCreationTimestamp())
+	if !p1Time.Equal(p2Time) {
+		return p1Time.Before(p2Time)
+	}
+	//  The object appearing first in alphabetical order by "{namespace}/{name}".
+	return fmt.Sprintf("%s/%s", a[i].GetNamespace(), a[i].GetName()) < fmt.Sprintf("%s/%s", a[j].GetNamespace(), a[j].GetName())
+}
+
+// AtomicDefaultsMergeStrategy implements a merge strategy that returns the target Policy if it exists,
+// otherwise it returns the source Policy.
+func AtomicDefaultsMergeStrategy(source, target machinery.Policy) machinery.Policy {
+	if source == nil {
+		return target
+	}
+	if target == nil {
+		return source
+	}
+
+	mergeableTargetPolicy := target.(MergeablePolicy)
+
+	if !mergeableTargetPolicy.Empty() {
+		return mergeableTargetPolicy.DeepCopyObject().(machinery.Policy)
+	}
+
+	return source.(MergeablePolicy).DeepCopyObject().(machinery.Policy)
+}
+
+var _ machinery.MergeStrategy = AtomicDefaultsMergeStrategy
+
+// AtomicOverridesMergeStrategy implements a merge strategy that overrides a target Policy with
+// a source one.
+func AtomicOverridesMergeStrategy(source, _ machinery.Policy) machinery.Policy {
+	if source == nil {
+		return nil
+	}
+	return source.(MergeablePolicy).DeepCopyObject().(machinery.Policy)
+}
+
+var _ machinery.MergeStrategy = AtomicOverridesMergeStrategy
+
+// PolicyRuleDefaultsMergeStrategy implements a merge strategy that merges a source Policy into a target one
+// by keeping the policy rules from the target and adding the ones from the source that do not exist in the target.
+func PolicyRuleDefaultsMergeStrategy(source, target machinery.Policy) machinery.Policy {
+	if source == nil {
+		return target
+	}
+	if target == nil {
+		return source
+	}
+
+	sourceMergeablePolicy := source.(MergeablePolicy)
+	targetMergeablePolicy := target.(MergeablePolicy)
+
+	// copy rules from the target
+	rules := targetMergeablePolicy.Rules()
+
+	// add extra rules from the source
+	for ruleID, rule := range sourceMergeablePolicy.Rules() {
+		if _, ok := targetMergeablePolicy.Rules()[ruleID]; !ok {
+			rules[ruleID] = MergeableRule{
+				Spec:   rule.Spec,
+				Source: source.GetLocator(),
+			}
+		}
+	}
+
+	mergedPolicy := targetMergeablePolicy.DeepCopyObject().(MergeablePolicy)
+	mergedPolicy.SetRules(rules)
+	return mergedPolicy
+}
+
+var _ machinery.MergeStrategy = PolicyRuleDefaultsMergeStrategy
+
+// PolicyRuleOverridesMergeStrategy implements a merge strategy that merges a source Policy into a target one
+// by using the policy rules from the source and keeping from the target only the policy rules that do not exist in
+// the source.
+func PolicyRuleOverridesMergeStrategy(source, target machinery.Policy) machinery.Policy {
+	sourceMergeablePolicy := source.(MergeablePolicy)
+	targetMergeablePolicy := target.(MergeablePolicy)
+
+	// copy rules from the source
+	rules := sourceMergeablePolicy.Rules()
+
+	// add extra rules from the target
+	for ruleID, rule := range targetMergeablePolicy.Rules() {
+		if _, ok := sourceMergeablePolicy.Rules()[ruleID]; !ok {
+			rules[ruleID] = rule
+		}
+	}
+
+	mergedPolicy := targetMergeablePolicy.DeepCopyObject().(MergeablePolicy)
+	mergedPolicy.SetRules(rules)
+	return mergedPolicy
+}
+
+var _ machinery.MergeStrategy = PolicyRuleOverridesMergeStrategy
+
+func DefaultsMergeStrategy(strategy string) machinery.MergeStrategy {
+	switch strategy {
+	case AtomicMergeStrategy:
+		return AtomicDefaultsMergeStrategy
+	case PolicyRuleMergeStrategy:
+		return PolicyRuleDefaultsMergeStrategy
+	default:
+		return AtomicDefaultsMergeStrategy
+	}
+}
+
+func OverridesMergeStrategy(strategy string) machinery.MergeStrategy {
+	switch strategy {
+	case AtomicMergeStrategy:
+		return AtomicOverridesMergeStrategy
+	case PolicyRuleMergeStrategy:
+		return PolicyRuleOverridesMergeStrategy
+	default:
+		return AtomicOverridesMergeStrategy
+	}
+}
+
+// EffectivePolicyForPath returns the effective policy for a given path, merging all policies in the path.
+// The policies in the path are sorted from the least specific to the most specific.
+// Only policies whose predicate returns true are considered.
+func EffectivePolicyForPath[T machinery.Policy](path []machinery.Targetable, predicate func(machinery.Policy) bool) *T {
+	policies := PoliciesInPath(path, predicate)
+	if len(policies) == 0 {
+		return nil
+	}
+
+	// map reduces the policies from most specific to least specific, merging them into one effective policy
+	effectivePolicy := lo.ReduceRight(policies, func(effectivePolicy machinery.Policy, policy machinery.Policy, _ int) machinery.Policy {
+		return effectivePolicy.Merge(policy)
+	}, policies[len(policies)-1])
+
+	concreteEffectivePolicy, _ := effectivePolicy.(T)
+	return &concreteEffectivePolicy
+}
+
+// OrderedPoliciesForPath gathers all policies in a path sorted from the least specific to the most specific.
+// Only policies whose predicate returns true are considered.
+func PoliciesInPath(path []machinery.Targetable, predicate func(machinery.Policy) bool) []machinery.Policy {
+	return lo.FlatMap(path, func(targetable machinery.Targetable, _ int) []machinery.Policy {
+		policies := lo.FilterMap(targetable.Policies(), func(policy machinery.Policy, _ int) (SortablePolicy, bool) {
+			p, sortable := policy.(SortablePolicy)
+			return p, sortable && predicate(p)
+		})
+		sort.Sort(PolicyByCreationTimestamp(policies))
+		return lo.Map(policies, func(policy SortablePolicy, _ int) machinery.Policy { return policy })
+	})
+}
+
+func PathID(path []machinery.Targetable) string {
+	s := strings.Join(lo.Map(path, machinery.MapTargetableToLocatorFunc), ">")
+	hash := sha256.Sum256([]byte(s))
+	return hex.EncodeToString(hash[:8])
+}

api/v1beta3/groupversion_info.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2021.
+Copyright 2024.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -14,23 +14,33 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-// Package v1beta3 contains API Schema definitions for the kuadrant v1beta3 API group
+// API schema definitions for the Kuadrant v1beta3 API group
 // +kubebuilder:object:generate=true
 // +groupName=kuadrant.io
 package v1beta3
 
 import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
-	"sigs.k8s.io/controller-runtime/pkg/scheme"
+	ctrl "sigs.k8s.io/controller-runtime/pkg/scheme"
 )
 
-var (
-	// GroupVersion is group version used to register these objects
-	GroupVersion = schema.GroupVersion{Group: "kuadrant.io", Version: "v1beta3"}
+// GroupName specifies the group name used to register the objects.
+const GroupName = "kuadrant.io"
 
-	// SchemeBuilder is used to add go types to the GroupVersionKind scheme
-	SchemeBuilder = &scheme.Builder{GroupVersion: GroupVersion}
+// GroupVersion specifies the group and the version used to register the objects.
+var GroupVersion = schema.GroupVersion{Group: GroupName, Version: "v1beta3"}
 
-	// AddToScheme adds the types in this group-version to the given scheme.
-	AddToScheme = SchemeBuilder.AddToScheme
-)
+// SchemeGroupVersion is group version used to register these objects
+// Deprecated: use GroupVersion instead.
+var SchemeGroupVersion = schema.GroupVersion{Group: GroupName, Version: "v1beta3"}
+
+// SchemeBuilder is used to add go types to the GroupVersionKind scheme
+var SchemeBuilder = &ctrl.Builder{GroupVersion: GroupVersion}
+
+// AddToScheme adds the types in this group-version to the given scheme.
+var AddToScheme = SchemeBuilder.AddToScheme
+
+// Resource takes an unqualified resource and returns a Group qualified GroupResource
+func Resource(resource string) schema.GroupResource {
+	return SchemeGroupVersion.WithResource(resource).GroupResource()
+}