Cherry-pick #21290 to 7.x: Thread safe sorted set (#21331)

Cherry-pick #21290 to 7.x: Thread safe sorted set  (#21331)

x-pack/elastic-agent/CHANGELOG.next.asciidoc

@@ -10,6 +10,7 @@
 - Docker container is not run as root by default. {pull}21213[21213]
 
 ==== Bugfixes
+- Thread safe sorted set {pull}21290[21290]
 - Copy Action store on upgrade {pull}21298[21298]
 - Include inputs in action store actions {pull}21298[21298]
 

x-pack/elastic-agent/pkg/sorted/set.go

@@ -6,13 +6,15 @@ package sorted
 
 import (
 	"sort"
+	"sync"
 )
 
 // Set is a sorted set that allow to iterate on they keys in an ordered manner, when
 // items are added or removed from the Set the keys are sorted.
 type Set struct {
 	mapped map[string]interface{}
 	keys   []string
+	rwlock sync.RWMutex
 }
 
 // NewSet returns an ordered set.
@@ -24,6 +26,9 @@ func NewSet() *Set {
 
 // Add adds an items to the set.
 func (s *Set) Add(k string, v interface{}) {
+	s.rwlock.Lock()
+	defer s.rwlock.Unlock()
+
 	_, ok := s.mapped[k]
 	if !ok {
 		s.keys = append(s.keys, k)
@@ -35,6 +40,9 @@ func (s *Set) Add(k string, v interface{}) {
 
 // Remove removes an items from the Set.
 func (s *Set) Remove(k string) {
+	s.rwlock.Lock()
+	defer s.rwlock.Unlock()
+
 	_, ok := s.mapped[k]
 	if !ok {
 		return
@@ -50,11 +58,17 @@ func (s *Set) Remove(k string) {
 
 // Get retrieves a specific values from the map and will return false if the key is not found.
 func (s *Set) Get(k string) (interface{}, bool) {
+	s.rwlock.RLock()
+	defer s.rwlock.RUnlock()
+
 	v, ok := s.mapped[k]
 	return v, ok
 }
 
 // Keys returns slice of keys where the keys are ordered alphabetically.
 func (s *Set) Keys() []string {
+	s.rwlock.RLock()
+	defer s.rwlock.RUnlock()
+
 	return append(s.keys[:0:0], s.keys...)
 }