Add entry points documentation for RecordFactory

doc/lsst.daf.butler/dev/entryPoints.rst

@@ -0,0 +1,34 @@
+.. _lsst.daf.butler-dev_entry_points:
+
+.. py:currentmodule:: lsst.daf.butler
+
+Support Entry Points
+--------------------
+
+Some functionality is enabled by utilizing the Python entry points system.
+Entry points are managed by the ``project.entry_points`` section of the ``pyproject.toml`` file.
+
+
+Command Line Subcommands
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+The entry points that support command-line subcommands are documented in :ref:`daf_butler_cli-entry-points`.
+
+ObsCore RecordFactory
+^^^^^^^^^^^^^^^^^^^^^
+
+`lsst.daf.butler.registry.obscore.RecordFactory` is the class that generates ObsCore records from Butler datasets.
+This conversion generally requires decisions to be made that depend on the dimension universe for the butler.
+The default implementation only works with the ``daf_butler`` dimension universe namespace.
+Alternative implementations can be registered using the ``butler.obscore_factory`` entry point group.
+The label associated with the entry point should correspond to the universe namespace.
+
+For example, a hypothetical entry point for the default namespace could be written in the ``pyproject.toml`` file as:
+
+.. code-block:: TOML
+
+    [project.entry-points.'butler.obscore_factory']
+    daf_butler = "lsst.daf.butler.registry.obscore._records.DafButlerRecordFactory"
+
+The function listed for the entry point should return the Python type that should be used to generate records.
+It is required to be a subclass of `lsst.daf.butler.registry.obscore.RecordFactory`.

doc/lsst.daf.butler/index.rst

@@ -85,6 +85,7 @@ You can find Jira issues for this module under the `daf_butler <https://jira.lss
    :maxdepth: 1
 
    dev/dataCoordinate.rst
+   dev/entryPoints.rst
 
 Butler Command Line Interface Development
 -----------------------------------------