Make it easy to use dataclass like models using familiar apis #6912
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Hi @philippjfr . Would you take a look at the design spec, i.e. the current files? Thanks. |
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #6912 +/- ##
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+ Coverage 81.71% 81.94% +0.22%
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Files 326 331 +5
Lines 48082 48861 +779
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+ Hits 39292 40040 +748
- Misses 8790 8821 +31 ☔ View full report in Codecov by Sentry. |
| await sleep(0.250) | ||
| return json.loads(model.json()) | ||
| exclude = list(layout_params) | ||
| def view_model(*args): |
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Why exclude attributes of a Pydantic model?
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Don't think there was a good reason.
No worries. I'm happy. |
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Not sure I love |
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Docs build now working. |
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When I click the run with pyodide button I see
It seems we need to add sqlite as a dependency. |
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FIXED I can see that the ipywidgets import panel as pn
import ipyleaflet as ipyl
pn.extension("ipywidgets")
leaflet_map = ipyl.Map(zoom=4)
viewer = pn.dataclass.ModelViewer(model=leaflet_map, sizing_mode="stretch_both")
pn.Row(pn.Column(viewer.param, scroll=True), viewer, height=400).servable()The problem is that the
If I change to use
then it can error ValueError: Attribute 'length' of Tuple parameter 'Map.bounds' is not of the correct length (0 instead of 2).
Traceback (most recent call last):
File "/home/jovyan/repos/private/panel/panel/_dataclasses/base.py", line 156, in sync_with_parameterized
setattr(model, field, parameter_value)
File "/home/jovyan/repos/private/panel/.venv/lib/python3.11/site-packages/traitlets/traitlets.py", line 715, in __set__
raise TraitError('The "%s" trait is read-only.' % self.name)
traitlets.traitlets.TraitError: The "bounds" trait is read-only.
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/jovyan/repos/private/panel/panel/io/handlers.py", line 389, in run
exec(self._code, module.__dict__)
File "/home/jovyan/repos/private/panel/script.py", line 8, in <module>
viewer = pn.dataclass.ModelViewer(model=leaflet_map, sizing_mode="stretch_both")
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/jovyan/repos/private/panel/panel/dataclass.py", line 159, in __init__
super().__init__(**params)
File "/home/jovyan/repos/private/panel/panel/viewable.py", line 302, in __init__
super().__init__(**params)
File "/home/jovyan/repos/private/panel/panel/dataclass.py", line 106, in __init__
utils.sync_with_parameterized(self.model, self, names=names)
File "/home/jovyan/repos/private/panel/panel/_dataclasses/base.py", line 159, in sync_with_parameterized
setattr(parameterized, parameter, field_value)
File "/home/jovyan/repos/private/panel/.venv/lib/python3.11/site-packages/param/parameterized.py", line 528, in _f
instance_param.__set__(obj, val)
File "/home/jovyan/repos/private/panel/.venv/lib/python3.11/site-packages/param/parameterized.py", line 530, in _f
return f(self, obj, val)
^^^^^^^^^^^^^^^^^
File "/home/jovyan/repos/private/panel/.venv/lib/python3.11/site-packages/param/parameterized.py", line 1498, in __set__
self._validate(val)
File "/home/jovyan/repos/private/panel/.venv/lib/python3.11/site-packages/param/parameters.py", line 1192, in _validate
self._validate_length(val, self.length)
File "/home/jovyan/repos/private/panel/.venv/lib/python3.11/site-packages/param/parameters.py", line 1185, in _validate_length
raise ValueError(
ValueError: Attribute 'length' of Tuple parameter 'Map.bounds' is not of the correct length (0 instead of 2). |
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FIXED
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FIXED Ahh. The dataclass functionality for Pydantic does not add specific parameter types yet. |
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Fixed by adding Our code instantiates pydantic models. Often they don't have default values. Instead initial values are required. This makes it a bit hard to use our features. Especially for creating forms with validation which a popular use case (c.f. pydantic-panel, streamlit-pydantic, dash-pydantic-form). For example the below test will currently raise an exception def test_to_parameterized_no_defaults():
from pydantic import BaseModel
class ExampleModel(BaseModel):
some_text: str
some_number: int
class ExampleModelParameterized(ModelParameterized):
_model_class = ExampleModel
ExampleModelParameterized()Something like the import panel as pn
from pydantic import BaseModel
import param
from panel._dataclasses.pydantic import PydanticUtils
pn.extension()
class ModelForm(pn.viewable.Viewer):
value = param.ClassSelector(class_=BaseModel, allow_None=True)
submit_button_visible = param.Boolean(default=True, label="Show Submit Button")
def __init__(self, model_class, submit_button_visible: bool=True, **params):
self._model_class = model_class
self._fields = list(model_class.model_fields.keys())
super().__init__(**params)
fields = model_class.model_fields
default_values = {field: PydanticUtils.create_parameter(model_class, field).default for field, info in fields.items() if info.is_required()}
model=model_class(**default_values)
self._model = model=model_class(**default_values)
parameters = list(ExampleModel.model_fields.keys())
parameterized = pn.dataclass.to_viewer(model)
parameterized.param.watch(self._update_value_on_parameter_change, parameters)
submit = pn.widgets.Button(name="Submit", button_type="primary", on_click=self._update_value, visible=self.param.submit_button_visible)
self._form = pn.Column(
pn.Param(parameterized, parameters=parameters),
submit)
def _update_value(self, *args):
self.value = self._model.copy(deep=True)
def _update_value_on_parameter_change(self, *args):
if not self.submit_button_visible:
self.value = self._model.copy(deep=True)
def __panel__(self):
return self._form
@param.depends("value")
def value_as_dict(self):
if not self.value:
return {}
return self.value.dict()
class ExampleModel(BaseModel):
some_text: str
some_number: int
some_boolean: bool
form = ModelForm(model_class=ExampleModel)
pn.Column(form, pn.pane.JSON(form.value_as_dict), form.param.submit_button_visible).servable() |
| return tuple(rx_values) | ||
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| class ModelForm(Viewer): |
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I added the ModelForm to support the form use case. This is the use case that pydantic-panel, streamlit-pydantic and dash-pydantic-form all support.
Its really a more general request as in #3687. We can solve this is several ways:
- not solve :-)
- document how to solve
- make general Panel form functionality
- add this dataclass specific form functionality.
What do you recommend @philippjfr ?
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Its worth noting that I achieve the form functionality a bit differently than the packages mentioned above. They translate pydantic fields to widgets while I translate pydantic fields to Parameters which Panel can translate to widgets. I.e. in my version we instantiate a Parameterized and then use Param. In the packages they can avoid instantiating a model before the user has filled out the form including required values.
Is my version the right way to go @philippjfr ?
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Great work! And the form use case should definitely be supported.
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I've tried to achieve almost feature parity with pydantic-panel. What is missing is Pydantic BaseModel attributes and pandas intervals.
pip install pydantic-panelimport pydantic
import panel as pn
from typing import List
from pydantic_panel.dispatchers import infer_widget
from datetime import datetime, date
import numpy as np
import pandas as pd
pn.extension("tabulator")
class ChildModel(pydantic.BaseModel):
name: str = "child"
class SomeModel(pydantic.BaseModel):
name: str = "some model"
child_field: ChildModel = ChildModel()
date_field: date = date(2024,1,2)
dateframe: pd.DataFrame = pd.DataFrame({"x": [1], "y": ["a"]})
datetime_field: datetime = datetime(2024,1,1)
dict_field: dict = {"a": 1}
float_field: float = 42
int_field: int = pydantic.Field(default=2, lt=10, gt=0, multiple_of=2)
list_field: list = [1, "two"]
nparray_field: np.ndarray = np.array([1, 2, 3])
str_field: str = pydantic.Field(default = "to", min_length=2, max_length=10)
tuple_field: tuple = ("a", 1)
class Config:
arbitrary_types_allowed = True # to allow np.array
model = SomeModel()
pydantic_panel_editor = pn.panel(model, sizing_mode="fixed") # Pydantic(model).layout[0]
print(type(pydantic_panel_editor))
panel_editor = pn.Param(pn.dataclass.to_parameterized(model))
pn.Row(
pydantic_panel_editor,
panel_editor,
).servable() |
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What else should be done here? |
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I'm still fully on board with the aims of this PR but it's simply too large a PR to make it into 1.5.0 at this point. |
Superseedes #6892.
Also motivated by me trying to demonstrate that you can just as well use Panel for geospatial applications as Solara by creating apps similar to https://github.com/opengeos/solara-geospatial/tree/main/pages. But currently Panel is harder to use because it requires adding more code for using
observerpattern.Scope: Currently ipywidgets, Pydantic models
Easy to view docs
Todo
panel.ipywidget.devdocs:TypeError: Cannot read properties of undefined (reading 'loader').self.param.add_parameter(parameter, param.Parameter())create_parameterof ipywidgets.create_parameterfor pydantic to add appropriate types of parameters.Maybe later
ModelForm.Promotion
Note: Features have been moved to
panel.dataclassmodule since this video was made.WidgetViewerhas been renamed toModelViewer.wrapping_ipywidgets.mp4
Design Principles
ModelViewerclass andcreate_rxfunction such that there are no dead ends and its testable.