cellmap_flow.finetune.json_files
================================

.. py:module:: cellmap_flow.finetune.json_files

.. autoapi-nested-parse::

   Writing a JSON file that another process, perhaps on another host, reads.

   A finetune run's metadata.json is the case in point: the training job and the
   dashboard's job monitor both update it, each from its own host. Written in
   place, with open('w') and json.dump, the file can be read while it is empty
   or cut short. Both import it from here: the training job cannot import the job manager,
   which is the dashboard's.



Functions
---------

.. autoapisummary::

   cellmap_flow.finetune.json_files.write_json_atomically


Module Contents
---------------

.. py:function:: write_json_atomically(path, data) -> None

   Write ``data`` to ``path`` as indented JSON, replacing the file whole.

   The JSON goes into a temporary file beside ``path``, named for this one
   write, which then replaces ``path``. So a reader finds the old file or
   the new one, never part of one: the trainer on its own host, another
   dashboard, or another thread of this one. And two writers never share a
   temporary file. Raises what serializing or writing raises (TypeError,
   OSError), with ``path`` left as it was and no temporary file behind.