fix: ignore non-nil but empty error strings in Describe/Alter client quotas responses

admin.go

@@ -1125,7 +1125,7 @@ func (ca *clusterAdmin) DescribeClientQuotas(components []QuotaFilterComponent,
 		return nil, err
 	}
 
-	if rsp.ErrorMsg != nil {
+	if rsp.ErrorMsg != nil && len(*rsp.ErrorMsg) > 0 {
 		return nil, errors.New(*rsp.ErrorMsg)
 	}
 	if rsp.ErrorCode != ErrNoError {
@@ -1157,6 +1157,9 @@ func (ca *clusterAdmin) AlterClientQuotas(entity []QuotaEntityComponent, op Clie
 	}
 
 	for _, entry := range rsp.Entries {
+		if entry.ErrorMsg != nil && len(*entry.ErrorMsg) > 0 {
+			return errors.New(*entry.ErrorMsg)
+		}
 		if entry.ErrorCode != ErrNoError {
 			return entry.ErrorCode
 		}

functional_admin_test.go

@@ -0,0 +1,125 @@
+//go:build functional
+// +build functional
+
+package sarama
+
+import (
+	"testing"
+)
+
+func TestFuncAdminQuotas(t *testing.T) {
+	checkKafkaVersion(t, "2.6.0.0")
+	setupFunctionalTest(t)
+	defer teardownFunctionalTest(t)
+
+	kafkaVersion, err := ParseKafkaVersion(FunctionalTestEnv.KafkaVersion)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	config := NewTestConfig()
+	config.Version = kafkaVersion
+	adminClient, err := NewClusterAdmin(FunctionalTestEnv.KafkaBrokerAddrs, config)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Check that we can read the quotas, and that they are empty
+	quotas, err := adminClient.DescribeClientQuotas(nil, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(quotas) != 0 {
+		t.Fatalf("Expected quotas to be empty at start, found: %v", quotas)
+	}
+
+	// Put a quota on default user
+	// /config/users/<default>
+	defaultUser := []QuotaEntityComponent{{
+		EntityType: QuotaEntityUser,
+		MatchType:  QuotaMatchDefault,
+	}}
+	produceOp := ClientQuotasOp{
+		Key:   "producer_byte_rate",
+		Value: 1024000,
+	}
+	if err = adminClient.AlterClientQuotas(defaultUser, produceOp, false); err != nil {
+		t.Fatal(err)
+	}
+
+	// Check that we now have a quota entry
+	quotas, err = adminClient.DescribeClientQuotas(nil, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(quotas) == 0 {
+		t.Fatal("Expected not empty quotas")
+	}
+	if len(quotas) > 1 {
+		t.Fatalf("Expected one quota entry, found: %v", quotas)
+	}
+
+	// Put a quota on specific client-id for a specific user
+	// /config/users/<user>/clients/<client-id>
+	specificUserClientID := []QuotaEntityComponent{
+		{
+			EntityType: QuotaEntityUser,
+			MatchType:  QuotaMatchExact,
+			Name:       "sarama",
+		},
+		{
+			EntityType: QuotaEntityClientID,
+			MatchType:  QuotaMatchExact,
+			Name:       "sarama-consumer",
+		},
+	}
+	consumeOp := ClientQuotasOp{
+		Key:   "consumer_byte_rate",
+		Value: 2048000,
+	}
+	if err = adminClient.AlterClientQuotas(specificUserClientID, consumeOp, false); err != nil {
+		t.Fatal(err)
+	}
+
+	// Check that we can query a specific quota entry
+	userFilter := QuotaFilterComponent{
+		EntityType: QuotaEntityUser,
+		MatchType:  QuotaMatchExact,
+		Match:      "sarama",
+	}
+	clientFilter := QuotaFilterComponent{
+		EntityType: QuotaEntityClientID,
+		MatchType:  QuotaMatchExact,
+		Match:      "sarama-consumer",
+	}
+	quotas, err = adminClient.DescribeClientQuotas([]QuotaFilterComponent{userFilter, clientFilter}, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(quotas) == 0 {
+		t.Fatal("Expected not empty quotas")
+	}
+	if len(quotas) > 1 {
+		t.Fatalf("Expected one quota entry, found: %v", quotas)
+	}
+	if quotas[0].Values[consumeOp.Key] != consumeOp.Value {
+		t.Fatalf("Expected specific quota value to be %f, found: %v", consumeOp.Value, quotas[0].Values[consumeOp.Key])
+	}
+
+	// Remove quota entries
+	deleteProduceOp := ClientQuotasOp{
+		Key:    produceOp.Key,
+		Remove: true,
+	}
+	if err = adminClient.AlterClientQuotas(defaultUser, deleteProduceOp, false); err != nil {
+		t.Fatal(err)
+	}
+
+	deleteConsumeOp := ClientQuotasOp{
+		Key:    consumeOp.Key,
+		Remove: true,
+	}
+	if err = adminClient.AlterClientQuotas(specificUserClientID, deleteConsumeOp, false); err != nil {
+		t.Fatal(err)
+	}
+}