================
 Batch Handlers
================

A :term:`batch handler` is responsible for the full lifecycle of a
:term:`batch`, e.g.:

* create new batch
* identify batch data file paths
* populate batch from data source
* modify batch per user request (e.g. via web app)
* execute batch

Whereas there is just "one" configured handler for most aspects of the
app (e.g. auth, email), since there is (often) more than one
:term:`batch type` there will be one handler configured for each batch
type.

Note that whereas WuttJamaican *does* define the batch/handler
interface, it does not actually come with any batch types, nor batch
handlers.

The :term:`app handler` is responsible for creating the batch handler
via :meth:`~wuttjamaican.app.AppHandler.get_batch_handler()`.  You
must specify the desired batch type "key" here (corresponds to
:attr:`~wuttjamaican.batch.BatchHandler.batch_type` on the handler)::

   app = config.get_app()
   handler = app.get_batch_handler("poser_foo")

Please see :doc:`/narr/batch/handlers` for further reading on these.