Add the forgotten utils module

pkg/utils/parallel.go

@@ -0,0 +1,43 @@
+package utils
+
+import (
+	"github.com/pkg/errors"
+	"sync"
+)
+
+// RunParallelFunctions runs a list of functions in parallel
+// returns nil if all functions return nil
+// returns an error which wraps all errors that occurred within the functions
+func RunParallelFunctions(functions []func() error) error {
+	var wg sync.WaitGroup
+	var mu sync.Mutex
+	var errorList []error
+
+	for _, function := range functions {
+		wg.Add(1)
+
+		// create an intermediate variable so each goroutine uses the correct function and doesn't get overwritten
+		function := function
+		go func(wg *sync.WaitGroup, mu *sync.Mutex) {
+			defer wg.Done()
+			err := function()
+			if err != nil {
+				mu.Lock()
+				errorList = append(errorList, err)
+				mu.Unlock()
+			}
+		}(&wg, &mu)
+	}
+
+	wg.Wait()
+
+	if len(errorList) > 0 {
+		err := errors.New("not all functions returned nil error")
+		for _, errorItem := range errorList {
+			err = errors.Wrap(err, errorItem.Error())
+		}
+		return err
+	}
+
+	return nil
+}