Angular calendar ui, load events from database

I started Angular js recently, and for a project, i have to use calendar-ui to manage events from database.

I managed to use the calendar correctly, using first events create manually. I tried now to bind with datas in database, but it's now comes the problem.

Here is my code :

$scope.eventsTab = [];
$scope.events = {};    
$http({
        url: "myurl",
        method: "POST",
        data: postData,
        headers: {'Content-Type': 'application/x-www-form-urlencoded'}
    }).success(function (data) {
            $scope.eventsTab.push({type:'session',title: data.title,start: new Date(y, m, 11, 15, 0),end: new Date(y, m, 20, 17, 30),url: 'http://google.com/'});
            $scope.events = {
                    color: 'orange',
                    textColor: 'white',
                    events: $scope.eventsTab
            };
    });
$scope.eventSources = [$scope.events];

And this is not working, the event is not loaded in my calendar. I think it is a problem dues to asynchronous matters, because if i put the code from "success" function juste before the following line

$scope.eventSources = [$scope.events];   

, the events appears in the calendar.

A last thing, when i use debug, i see correctly the data form the database .

Could you help me please?

Thanks !

Edit 1

If i put the code like this

$http({
    url: "myurl",
    method: "POST",
    data: postData,
    headers: {'Content-Type': 'application/x-www-form-urlencoded'}
}).success(function (data) {
        $scope.eventsTab.push({type:'session',title: data.title,start: new Date(y, m, 11, 15, 0),end: new Date(y, m, 20, 17, 30),url: 'http://google.com/'});
        $scope.events = {
                color: 'orange',
                textColor: 'white',
                events: $scope.eventsTab
        };
        $scope.eventSources = [$scope.events];
});

I got the error TypeError: Cannot read property 'length' of undefined

And with the following code

$http({
    url: "myurl",
    method: "POST",
    data: postData,
    headers: {'Content-Type': 'application/x-www-form-urlencoded'}
}).success(function (data) {
        $scope.eventsTab.push({type:'session',title: data.title,start: new Date(y, m, 11, 15, 0),end: new Date(y, m, 20, 17, 30),url: 'http://google.com/'});
        $scope.events = {
                color: 'orange',
                textColor: 'white',
                events: $scope.eventsTab
        };
        $scope.eventSources = [$scope.events];
});
$scope.eventSources = [$scope.events];

No error, but the same problem : the event is not displayed in the calendar.