doit task decorator


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doit uses plain python dictionaries to define tasks. Many, many people ask for a decorator based syntax. So here it is:

##########################################################
## the decorator

def task(*args, **meta):
    """decorator to attach task metadata to a function
    decorated function will become the task's action
    """
    def make_task(func):
        func._doit_task = True
        func._doit_meta = meta
        return func

    if args:
        # decorator without parameters
        return make_task(args[0])
    else:
        # decorator with task metadata
        return make_task


###########################################################
## task definition

DOIT_CONFIG = {'verbosity': 2}


@task
def simple():
    print "ho"

@task(file_dep=['dodo.py'])
def hello():
    print "hi"




############################################################
### boilerplate - convert decorated stuff to default doit style tasks

def task_all():
    for name, obj in globals().iteritems():
        if getattr(obj, '_doit_task', False):
            task_dict = {'basename': name, 'actions': [obj]}
            task_dict.update(obj._doit_meta)
            yield task_dict

Note that this will work with any version of doit there is no need to have any modification in doit internal code.

doit is a generic tool that aims to by different kinds of applications. There is no one task definition interface that will make everyone happy. doit provides the most basic and flexible one based on dicts...

I must agree that this decorator interface looks more readable :) But it has many limitations and can be used only for trivial tasks.

Limitations:

  • only one action per task
  • no support for command line (shell) actions
  • not easy to create several tasks with same actions

You could go one step further and create a custom task loader, so you could get rid of the task_all. I might add something like this for next doit release...

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