django 有没有什么监控 model 字段修改的插件。

某个字段修改，记录下修改人修改前后的值，现在我在 ModelForm clean 函数里处理了下，感觉。。。。挺蛋疼的。

class SynthesisStepForm(BootstrapModelForm):
    class Meta:
        model = SynthesisStep
        fields = ('title', 'version', 'condition', 'yield_rate', 'testing', 'stype')
        widgets = {
            'testing': forms.Textarea(attrs={'rows': '4', 'cols': '100', 'style': 'width:auto;'}),
            'condition': forms.Textarea(attrs={'rows': '4', 'cols': '100', 'style': 'width:auto;'})
        }

    def clean(self):
        """
        用于监控字段被修改
        :return:
        """
        update_fields = ('title', 'version', 'condition', 'yield_rate', 'testing', 'stype')
        cleaned_data = super(BootstrapModelForm, self).clean()
        update_note = supervisory_update_fields(self, cleaned_data, update_fields)
        self._update_note = update_note

        return cleaned_data

def supervisory_update_fields(form_obj, cleaned_data, update_fields):
    """
    用于监控 form 提交字段的变化
    :param form_obj:
    :param cleaned_data:
    :param update_fields:
    :return:
    """
    update_note = ''
    if form_obj.instance.pk:  # new instance only
        changed_data = form_obj.changed_data
        for data in changed_data:
            if data in update_fields:
                try:
                    old_field = eval('form_obj.instance.{0}'.format(data))
                    new_field = cleaned_data[data]
                    if old_field != new_field:
                        update_note = update_note + '{2} is modified , from "{0}" to "{1}"\n'.format(old_field,new_field, data)
                except Exception as e:
                    pass

    return update_note