TaskFactory

class lsst.pipe.base.TaskFactory

Bases: object

Abstract base class for task factory.

Task factory is responsible for importing PipelineTask subclasses by name and creating instances of these classes.

Methods Summary

loadTaskClass(taskName)	Locate and import PipelineTask class.
makeTask(taskClass, config, overrides, butler)	Create new PipelineTask instance from its class.

Methods Documentation

loadTaskClass(taskName)

Locate and import PipelineTask class.

Returns tuple of task class and its full name, None is returned for both if loading fails.

Parameters:

taskName : str

Name of the PipelineTask class, interpretation depends entirely on activator, e.g. it may or may not include dots.

Returns:

taskClass : type

PipelineTask class object, or None on failure.

taskName : str

Full task class name including package and module, or None on failure.

Raises:

ImportError

Raised if task class cannot be imported.

TypeError

Raised if imported class is not a PipelineTask.

makeTask(taskClass, config, overrides, butler)

Create new PipelineTask instance from its class.

Parameters:

taskClass : type

PipelineTask sub-class.

config : pex.Config or None

Configuration object, if None then use task-defined configuration class (taskClass.ConfigClass) to create new instance.

overrides : ConfigOverrides or None

Configuration overrides, this should contain all overrides to be applied to a default task config, including instrument-specific, obs-package specific, and possibly command-line overrides. This parameter is exclusive with config, only one of the two can be specified as not-None.

butler : Butler or None

Butler instance used to obtain initialization inputs for PipelineTasks. If None, some PipelineTasks will not be usable

Returns:

task : PipelineTask

Instance of a PipelineTask class or None on errors.

Raises:

Any exceptions that are raised by PipelineTask constructor or its

configuration class are propagated back to caller.