Allow to reset key store and stop key fetching

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

goKMS/kms/peers/etsi14Quantummodule.go

@@ -31,7 +31,7 @@ type ETSI014HTTPQuantumModule struct {
 	keyFetchInterval int
 	keyFetchAmount   int64
 	maxKeyFillLevel  uint64
-	stopFetch        chan struct{}
+	stopFetch        context.CancelFunc
 }
 
 func NewETSI014HTTPQuantumModule(addr, kmsId, localSAEID, targetSAEID string, tlsConfig config.TLSConfig, master bool, keyFetchInterval int, keyFetchAmount int64, maxKeyFillLevel uint64) (*ETSI014HTTPQuantumModule, error) {
@@ -107,7 +107,8 @@ func (qm *ETSI014HTTPQuantumModule) Client() *etsi14ClientImpl.ClientImpl {
 }
 
 func (qm *ETSI014HTTPQuantumModule) Initialize() error {
-	qm.stopFetch = make(chan struct{}, 0)
+	var ctx context.Context
+	ctx, qm.stopFetch = context.WithCancel(context.Background())
 
 	// start polling keys
 	if qm.master {
@@ -117,8 +118,14 @@ func (qm *ETSI014HTTPQuantumModule) Initialize() error {
 			defer ticker.Stop()
 
 			// immediately start with the ticker instead of waiting the defined amount
-			for ; true; <-ticker.C {
-				qm.doKeyFetching()
+		RestartFetchLoop:
+			for {
+				select {
+				case <-ticker.C:
+					qm.doKeyFetching(ctx)
+				case <-ctx.Done():
+					break RestartFetchLoop
+				}
 			}
 		}()
 	}
@@ -127,7 +134,7 @@ func (qm *ETSI014HTTPQuantumModule) Initialize() error {
 
 func (qm *ETSI014HTTPQuantumModule) StopKeyFetching() {
 	if qm.master {
-		close(qm.stopFetch)
+		qm.stopFetch()
 	}
 }
 
@@ -185,18 +192,19 @@ func (qm *ETSI014HTTPQuantumModule) GetKeyWithIds(keyIds []etsi14ClientGenerated
 	return container, nil
 }
 
-func (qm *ETSI014HTTPQuantumModule) doKeyFetching() {
+func (qm *ETSI014HTTPQuantumModule) doKeyFetching(ctx context.Context) {
 	ticker := time.NewTicker(time.Duration(qm.keyFetchInterval) * time.Second)
 	defer ticker.Stop()
 
 	failedAttemps := 0
 
+FetchLoop:
 	for {
 		select {
 		case <-ticker.C:
 			if failedAttemps == maxFailedKeyRequestAttempts {
 				log.Errorf("stopped trying to fetch keys from qkd module after %d tries", failedAttemps)
-				break
+				break FetchLoop
 			}
 
 			if qm.keyStore.Length() < int(qm.maxKeyFillLevel) {
@@ -233,9 +241,8 @@ func (qm *ETSI014HTTPQuantumModule) doKeyFetching() {
 
 				failedAttemps = 0
 			}
-		case <-qm.stopFetch:
-			break
+		case <-ctx.Done():
+			break FetchLoop
 		}
 	}
-
 }