doit - example of how to detect obsolote targets in tasks

obsolete.py

DOIT_CONFIG = {'verbosity': 2}


def targets_diff(task, values):
    """to be used as uptodate check - check if targets changed
    it also save the 'tdiff' to be used by other actions
    """
    now_list = task.targets

    # set value to be saved if execution is successful
    def save_list():
        return {'target_list': now_list}
    task.value_savers.append(save_list)

    # get value saved on last successful execution
    last_success = values.get('target_list', None)

    # calculate diff between previous list and now
    set_new = set(now_list)
    if last_success is not None:
        set_old = set(last_success)
        diff_dict = {
            'added': (set_new - set_old),
            'removed': (set_old - set_new),
            }
    else:
        diff_dict = {
            'added': set_new,
            'removed': set(),
            }

    # hack - add calculated diff to task.options to be used by its actions
    task.options = {'tdiff': diff_dict}

    return now_list == last_success


def task_x():
    def print_diff(tdiff):
        """example of action that use target change info,
        could remove obsolote targets"""
        print tdiff

    # simulate targets changing
    targets = ['1','2','3']
    #targets = ['2','3','4']

    return {
        'targets': targets,
        'actions': ['echo execute task', print_diff],
        'uptodate': [targets_diff],
        }