semvec/pypi-packages huggingface dataset:
dj-obj-update 0.6.0
`dj-obj-update` helps you update an object but only saves if something changed.
Requires Python: >=3.4

# Django Object Update

[![Build Status](https://travis-ci.org/crccheck/dj-obj-update.svg?branch=master)](https://travis-ci.org/crccheck/dj-obj-update)

`dj-obj-update` is a module that helps you do two things while updating
an object:

1.  Only do a save if something changed
2.  Log what changed (the logger name is `obj_update` and only outputs
    `logging.DEBUG`)

## Installation

    pip install dj-obj-update

## Usage

### Updating an object

    from obj_update import obj_update

    new_data = {
        'flavor': 'chocolate',
    }
    for obj in queryset:
        obj_update(obj, new_data)

### Dry run updating an object

    from obj_update import obj_update

    logger.setLevel(logging.DEBUG)  # see "Logging changes" below

    new_data = {
        'flavor': 'chocolate',
    }
    for obj in queryset:
        obj_update(obj, new_data, update_fields=[])

### Replacement for [`update_or_create`]

    from obj_update import obj_update_or_create

    choice, created = obj_update_or_create(
        Choice,
        question=question,
        defaults={'choice_text': 'Flour or corn?'},
    )

[`update_or_create`]: https://docs.djangoproject.com/en/stable/ref/models/querysets/#update-or-create

### Dealing with `auto_now` fields

By default, `dj-obj-update` constructs an `update_fields` when it saves.
This means fields like the primary key, `auto_now`, and `auto_now_add`
might not get saved. If you need these, you should set
`update_fields=None`. Usage is the same as Django's [`update_fields`]

[`update_fields`]: https://docs.djangoproject.com/en/stable/ref/models/instances/#specifying-which-fields-to-save

### Logging changes

Using `python-json-logger`:

    import logging
    from pythonjsonlogger.jsonlogger import JsonFormatter

    logger = logging.getLogger('obj_update')
    handler = logging.FileHandler('log/my_obj_changes.log')
    handler.setFormatter(JsonFormatter())
    logger.addHandler(handler)
    logger.setLevel(logging.DEBUG)

With JSON logging, you'll get messages like:

    {"message": "[text hello->hello2]", "model": "FooModel", "pk": 1, "changes": {"text": {"old": "hello", "new": "hello2"}}}

With a normal logger, you'll still get output, but it won't have as much
information:

    [text hello->hello2]

You can selectively log object creation or updates. For example, if you don't
expect objects to be created, you can only enable the `obj_update.create`
logger. Likewise, you can only enable the `obj_update.update` logger to ignore
creation. See the `logging.config` example at the top of
[test_obj_update](./test_obj_update) for an example.