added manger to keep track of go routines in the services (#2869)

- added manager to wait for all go routines to end before exit
- code refactor
- renamed Manafer to Interface and GoRoutineManager to GroupManager
- replaced some go routine calls with manager Add func
- added unit tests for manager

pkg/utils/manager/manager.go

@@ -0,0 +1,62 @@
+package manager
+
+import (
+	"context"
+	"sync"
+	"time"
+)
+
+var _ Interface = &GroupManager{}
+
+// Interface keeps track of the go routines in the system and can be used to gracefully shutdown the
+// the system by waiting for completion of go routines added to it.
+type Interface interface {
+	// Add will start a go routine for the given "function" and adds it to the list of go routines
+	// and will also remove the "function" from the list when it completes
+	Add(ctx context.Context, function func(context.Context))
+
+	// Wait blocks the execution of the process until all the go routines in the manager are completed.
+	Wait()
+
+	// WaitWithTimeout blocks the execution of the process until timeout or till all all the go routines in the manager are completed
+	WaitWithTimeout(timeout time.Duration) error
+}
+
+type GroupManager struct {
+	wg sync.WaitGroup
+}
+
+func New() Interface {
+	return &GroupManager{
+		wg: sync.WaitGroup{},
+	}
+}
+func (g *GroupManager) Add(ctx context.Context, f func(context.Context)) {
+	g.wg.Add(1)
+	go func() {
+		defer g.wg.Done()
+		f(ctx)
+	}()
+}
+
+func (g *GroupManager) Wait() {
+	g.wg.Wait()
+}
+
+func (g *GroupManager) WaitWithTimeout(timeout time.Duration) error {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	done := make(chan struct{})
+	go func() {
+		g.wg.Wait()
+		close(done)
+	}()
+
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-done:
+		return nil
+	}
+}

pkg/utils/manager/manager_test.go

@@ -0,0 +1,65 @@
+package manager
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestAddAndWait(t *testing.T) {
+	mgr := New()
+
+	value := 10
+	expectedValue := 11
+
+	mgr.Add(context.Background(), func(ctx context.Context) {
+		time.Sleep(1 * time.Second)
+		value = expectedValue
+	})
+
+	mgr.Wait()
+	require.Equal(t, expectedValue, value, "manager did not wait for go routine to complete")
+}
+
+func TestAddWithContextCancel(t *testing.T) {
+	mgr := New()
+
+	value := 10
+	expectedValue := 11
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	mgr.Add(ctx, func(ctx context.Context) {
+		<-ctx.Done()
+		value = 11
+	})
+
+	go cancel()
+	mgr.Wait()
+	require.Equal(t, expectedValue, value, "manager did not wait for go routine to complete when context is cancelled")
+}
+
+func TestAddAndWaitWithTimeout(t *testing.T) {
+	mgr := New()
+
+	value := 10
+
+	mgr.Add(context.Background(), func(ctx context.Context) {
+		time.Sleep(2 * time.Second)
+	})
+
+	err := mgr.WaitWithTimeout(1 * time.Second)
+	require.NotNil(t, err, "manager WaitWithTimeout did not return an error when timeout exceeded")
+
+	expectedValue := 11
+	mgr.Add(context.Background(), func(ctx context.Context) {
+		time.Sleep(100 * time.Millisecond)
+		value = expectedValue
+	})
+
+	err = mgr.WaitWithTimeout(1 * time.Second)
+	require.Nil(t, err, "manager returned error even though all go routins completed successfully before timeout")
+	require.Equal(t, expectedValue, value)
+}