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/httpserver/server.go

@@ -6,10 +6,11 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/fission/fission/pkg/utils/manager"
 	"go.uber.org/zap"
 )
 
-func StartServer(ctx context.Context, log *zap.Logger, svc string, port string, handler http.Handler) {
+func StartServer(ctx context.Context, log *zap.Logger, mgr manager.Interface, svc string, port string, handler http.Handler) {
 	if !strings.Contains(port, ":") {
 		port = fmt.Sprintf(":%s", port)
 	}
@@ -19,13 +20,13 @@ func StartServer(ctx context.Context, log *zap.Logger, svc string, port string,
 	}
 	l := log.With(zap.String("service", svc), zap.String("addr", server.Addr))
 	l.Info("starting server")
-	go func() {
+	mgr.Add(ctx, func(ctx context.Context) {
 		if err := server.ListenAndServe(); err != nil {
 			if err != http.ErrServerClosed {
 				l.Error("server error", zap.Error(err))
 			}
 		}
-	}()
+	})
 	<-ctx.Done()
 	l.Info("shutting down server")
 	if err := server.Shutdown(ctx); err != nil {

pkg/utils/httpserver/server_test.go

@@ -12,9 +12,13 @@ import (
 	"go.uber.org/zap"
 
 	"github.com/fission/fission/pkg/utils/loggerfactory"
+	"github.com/fission/fission/pkg/utils/manager"
 )
 
 func TestStartServer(t *testing.T) {
+	mgr := manager.New()
+	defer mgr.Wait()
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	logger := loggerfactory.GetLogger()
@@ -26,7 +30,10 @@ func TestStartServer(t *testing.T) {
 			logger.Error("failed to write response", zap.Error(err))
 		}
 	}))
-	go StartServer(ctx, logger, "test", "8999", m)
+
+	mgr.Add(ctx, func(ctx context.Context) {
+		StartServer(ctx, logger, mgr, "test", "8999", m)
+	})
 
 	tests := []struct {
 		Name       string