The core of Invoke’s execution model involves one or more Collection objects. While these may be created programmatically, in typical use Invoke will create them for you from Python modules it finds or is told to use.
Task module discovery¶
With no other configuration, simply calling
invoke will look for a single
Python module or package named
tasks, and will treat it as the root
tasks (or any other name given via loading configuration
options) is searched for in the following ways:
First, if a valid tasks module by that name already exists on Python’s sys.path, no more searching is done – that module is selected.
Failing that, search towards the root of the local filesystem, starting with the user’s current working directory (os.getcwd) and try importing again with each directory temporarily added to
Due to how Python’s import machinery works, this approach will always favor a package directory (
__init__.py) over a module file (
tasks.py) in the same location.
If a candidate is found and successfully imported, its parent directory will stay on
sys.pathduring the rest of the Python session – this allows task code to make convenient assumptions concerning sibling modules’ importability.
Candidate modules/packages are introspected to make sure they can actually be
used as valid task collections. Any that fail are discarded, the
munging done to import them is reverted, and the search continues.
Configuring the loading process¶
You can configure the above behavior, requesting that Invoke alter the collection name searched for and/or the path where filesystem-level loading starts looking.
For example, you may already have a project-level
tasks.py that you can’t
easily rename; or you may want to host a number of tasks collections stored
outside the project root and make it easy to switch between them; or any number
Both the sought collection name and the search root can be specified via configuration file options or as runtime CLI flags:
Change the collection name: Set the
tasks.collection_nameconfiguration option, or use
--collection. It should be a Python module name and not a file name (so
Change the root search path: Configure
--search-root. This value may be any valid directory path.