add options for GenericParallelContainers function

parallel.go

@@ -7,15 +7,13 @@ import (
 )
 
 const (
-	MaxGenericWorkers = 8
+	defaultWorkersCount = 8
 )
 
-type GenericParallelErrors struct {
-	Errors []GenericContainerRequestError
-}
-
-func (gpe GenericParallelErrors) Error() string {
-	return fmt.Sprintf("%v", gpe.Errors)
+// GenericParallelOptions represents additional options for running
+// * WorkersCount - count of parallel workers. if field empty(zero), default value will be 'defaultWorkersCount'
+type GenericParallelOptions struct {
+	WorkersCount int
 }
 
 // GenericContainerRequestError represents error from parallel request
@@ -24,6 +22,14 @@ type GenericContainerRequestError struct {
 	Error   error
 }
 
+type GenericParallelErrors struct {
+	Errors []GenericContainerRequestError
+}
+
+func (gpe GenericParallelErrors) Error() string {
+	return fmt.Sprintf("%v", gpe.Errors)
+}
+
 func genericContainerRunner(
 	ctx context.Context,
 	requests <-chan GenericContainerRequest,
@@ -45,8 +51,12 @@ func genericContainerRunner(
 }
 
 // GenericParallelContainers creates a generic containers with parameters in parallel mode
-func GenericParallelContainers(ctx context.Context, reqs []GenericContainerRequest) ([]Container, error) {
-	tasksChanSize := MaxGenericWorkers
+func GenericParallelContainers(ctx context.Context, reqs []GenericContainerRequest, opt GenericParallelOptions) ([]Container, error) {
+	if opt.WorkersCount == 0 {
+		opt.WorkersCount = defaultWorkersCount
+	}
+
+	tasksChanSize := opt.WorkersCount
 	if tasksChanSize > len(reqs) {
 		tasksChanSize = len(reqs)
 	}

parallel_test.go

@@ -69,7 +69,7 @@ func TestGenericParallelContainers(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			res, err := GenericParallelContainers(context.Background(), tc.reqs)
+			res, err := GenericParallelContainers(context.Background(), tc.reqs, GenericParallelOptions{})
 
 			if err != nil && tc.expErrors > 0 {
 				e, _ := err.(GenericParallelErrors)