Action Pipeline

PyScaffold organizes the generation of a project into a series of steps with well defined purposes. As shown in the figure bellow, each step is called action and is implemented as a simple function that receives two arguments: a project structure and a dict with options (some of them parsed from command line arguments, other from default values).

An action MUST return a tuple also composed by a project structure and a dict with options. The return values, thus, are usually modified versions of the input arguments. Additionally an action can also have side effects, like creating directories or adding files to version control. The following pseudo-code illustrates a basic action:

def action(project_structure, options):
    new_struct, new_opts = modify(project_structure, options)
    some_side_effect()
    return new_struct, new_opts

The output of each action is used as the input of the subsequent action, forming a pipeline. Initially the structure argument is just an empty dict. Each action is uniquely identified by a string in the format <module name>:<function name>, similarly to the convention used for a setuptools entry point. For example, if an action is defined in the action function of the extras.py file that is part of the pyscaffoldext.contrib project, the action identifier is pyscaffoldext.contrib.extras:action.

By default, the sequence of actions taken by PyScaffold is:

1. pyscaffold.actions:get_default_options

2. pyscaffold.actions:verify_options_consistency

3. pyscaffold.structure:define_structure

4. pyscaffold.actions:verify_project_dir

5. pyscaffold.update:version_migration

6. pyscaffold.structure:create_structure

7. pyscaffold.actions:init_git

8. pyscaffold.actions:report_done

(as given by pyscaffold.actions.DEFAULT)

The project structure is usually empty until define_structure This action just loads the in-memory dict representation, that is only written to disk by the create_structure action.

Note that, this sequence varies according to the command line options. To retrieve an updated list, please use putup --list-actions or putup --dry-run.