Motor Tailable Cursor Example

This example describes using Motor with Tornado. Beginning in version 0.5 Motor can also integrate with asyncio instead of Tornado.

A cursor on a capped collection can be tailed using fetch_next():

@gen.coroutine
def tail_example():
    results = []
    collection = db.my_capped_collection
    cursor = collection.find(cursor_type=CursorType.TAILABLE, await_data=True)
    while True:
        if not cursor.alive:
            now = datetime.datetime.utcnow()
            # While collection is empty, tailable cursor dies immediately
            yield gen.sleep(1)
            cursor = collection.find(cursor_type=CursorType.TAILABLE, await_data=True)

        if (yield cursor.fetch_next):
            results.append(cursor.next_object())
            print results

See also

Tailable cursors