Provisioning: Fix admin reloading of dashboard configuration (#92462)

* Set dashboard provisioner before provisioning dashboards
* Test provisioner instantiation during dashboard provisioning

pkg/services/provisioning/provisioning.go

@@ -235,13 +235,18 @@ func (ps *ProvisioningServiceImpl) ProvisionPlugins(ctx context.Context) error {
 }
 
 func (ps *ProvisioningServiceImpl) ProvisionDashboards(ctx context.Context) error {
+	err := ps.setDashboardProvisioner()
+	if err != nil {
+		return fmt.Errorf("%v: %w", "Failed to create provisioner", err)
+	}
+
 	ps.mutex.Lock()
 	defer ps.mutex.Unlock()
 
 	ps.cancelPolling()
 	ps.dashboardProvisioner.CleanUpOrphanedDashboards(ctx)
 
-	err := ps.dashboardProvisioner.Provision(ctx)
+	err = ps.dashboardProvisioner.Provision(ctx)
 	if err != nil {
 		// If we fail to provision with the new provisioner, the mutex will unlock and the polling will restart with the
 		// old provisioner as we did not switch them yet.

pkg/services/provisioning/provisioning_test.go

@@ -108,6 +108,19 @@ func TestProvisioningServiceImpl(t *testing.T) {
 
 		assert.True(t, errors.Is(serviceTest.serviceError, provisioningErr))
 	})
+	t.Run("Should set dashboard provisioner when provisioning dashboards", func(t *testing.T) {
+		// The first dashboard provisioner instantiation takes place when
+		// setDashboardProvisioner() is called in setup(t).
+		serviceTest := setup(t)
+		// The second dashboard provisioner instantiation takes place when
+		// Run(ctx) is executed.
+		serviceTest.startService()
+
+		serviceTest.cancel()
+		serviceTest.waitForStop()
+
+		assert.Equal(t, 2, serviceTest.dashboardProvisionerInstantiations)
+	})
 }
 
 type serviceTestStruct struct {
@@ -121,6 +134,8 @@ type serviceTestStruct struct {
 	startService func()
 	cancel       func()
 
+	dashboardProvisionerInstantiations int
+
 	mock    *dashboards.ProvisionerMock
 	service *ProvisioningServiceImpl
 }
@@ -141,6 +156,7 @@ func setup(t *testing.T) *serviceTestStruct {
 
 	service, err := newProvisioningServiceImpl(
 		func(context.Context, string, dashboardstore.DashboardProvisioningService, org.Service, utils.DashboardStore, folder.Service) (dashboards.DashboardProvisioner, error) {
+			serviceTest.dashboardProvisionerInstantiations++
 			return serviceTest.mock, nil
 		},
 		nil,