mirror of
https://github.com/p2p-ld/numpydantic.git
synced 2024-11-10 00:34:29 +00:00
144 lines
No EOL
4.2 KiB
Markdown
144 lines
No EOL
4.2 KiB
Markdown
# Interfaces
|
|
|
|
Interfaces are the bridge between the abstract {class}`~numpydantic.NDArray` specification
|
|
and concrete array libraries. They are subclasses of the abstract {class}`.Interface`
|
|
class.
|
|
|
|
They contain methods for coercion, validation, serialization, and any other
|
|
implementation-specific functionality.
|
|
|
|
## Discovery
|
|
|
|
Interfaces are discovered through the {meth}`.Interface.interfaces` method -
|
|
returning all subclasses of `Interface`. To use a custom interface, it just
|
|
needs to be defined/imported by the time you intend to use it when instantiating
|
|
a pydantic model.
|
|
|
|
Each interface implements a {meth}`.Interface.enabled` method that determines
|
|
whether that interface can be used. Typically that means checking if its dependencies
|
|
are present in the environment, but can also control conditional use.
|
|
|
|
## Matching
|
|
|
|
When a pydantic model is instantiated and an `NDArray` is to be validated,
|
|
{meth}`.Interface.match` first, uh, finds the matching interface.
|
|
|
|
Each interface must define a {meth}`.Interface.check` class that accepts the
|
|
array to be validated and returns whether it can be used. Interfaces can
|
|
have any `check`ing logic they want, and so can eg. determine if a path
|
|
is a particular type of file, but should return quickly and do little work
|
|
since they are called frequently.
|
|
|
|
Validation fails if an argument doesn't match any interface.
|
|
|
|
```{note}
|
|
The {class}`.NumpyInterface` is special cased and is only checked if
|
|
no other interface matches. It attempts to cast the input argument to a
|
|
{class}`numpy.ndarray` to see if it is arraylike, and since many
|
|
lazy-loaded array libraries will attempt to load the whole array into memory
|
|
when cast to an `ndarray`, we only try as a last resort.
|
|
```
|
|
|
|
## Validation
|
|
|
|
Validation is a chain of lifecycle methods, each of which can be overridden
|
|
for interfaces to implement custom behavior that matches the array format.
|
|
|
|
{meth}`.Interface.validate` calls the following methods, in order:
|
|
|
|
An initial hook for modifying the input data before validation, eg.
|
|
if it needs to be coerced or wrapped in some proxy class. This method
|
|
should accept all and only the types specified in that interface's
|
|
{attr}`~.Interface.input_types`.
|
|
|
|
- {meth}`.Interface.before_validation`
|
|
|
|
A cluster of methods for validating dtype.
|
|
Separating these methods allow for array formats that store dtype information
|
|
in a nonstandard attribute, require additional coercion, or for implementing
|
|
custom exception handlers or rescuers.
|
|
Check the method signatures and return types
|
|
when overriding and the docstrings for details.
|
|
|
|
- {meth}`.Interface.get_dtype`
|
|
- {meth}`.Interface.validate_dtype`
|
|
- {meth}`.Interface.raise_for_dtype`
|
|
|
|
A halftime hook for modifying the array or bailing early between validation phases.
|
|
|
|
- {meth}`.Interface.after_validate_dtype`
|
|
|
|
A cluster of methods for validating shape, similar to the dtype cluster.
|
|
|
|
- {meth}`.Interface.get_shape`
|
|
- {meth}`.Interface.validate_shape`
|
|
- {meth}`.Interface.raise_for_shape`
|
|
|
|
A final hook for modifying the array before passing it to be assigned to the field.
|
|
This method should return an object matching the interface's {attr}`~.Interface.return_type`.
|
|
- {meth}`.Interface.after_validation`
|
|
|
|
## Diagram
|
|
|
|
```{todo}
|
|
Sorry this is unreadable, need to recall how to change the theme for
|
|
generated mermaid diagrams but it is very late and i want to push this.
|
|
```
|
|
|
|
```{mermaid}
|
|
flowchart LR
|
|
classDef data fill:#2b8cee,color:#ffffff;
|
|
classDef X fill:transparent,border:none,color:#ff0000;
|
|
|
|
input
|
|
|
|
subgraph Interface
|
|
match
|
|
end
|
|
|
|
subgraph Numpy
|
|
numpy_check["check"]
|
|
end
|
|
|
|
subgraph Dask
|
|
direction TB
|
|
|
|
dask_check["check"]
|
|
|
|
subgraph Validation
|
|
direction TB
|
|
|
|
before_validation --> validate_dtype
|
|
validate_dtype --> validate_shape
|
|
validate_shape --> after_validation
|
|
end
|
|
|
|
dask_check --> Validation
|
|
|
|
end
|
|
|
|
subgraph Zarr
|
|
zarr_check["check"]
|
|
end
|
|
|
|
subgraph Model
|
|
output
|
|
end
|
|
|
|
zarr_x["X"]
|
|
numpy_x["X"]
|
|
|
|
input --> match
|
|
match --> numpy_check
|
|
match --> zarr_check
|
|
match --> Dask
|
|
zarr_check --> zarr_x
|
|
numpy_check --> numpy_x
|
|
|
|
Validation --> Model
|
|
|
|
class input data
|
|
class output data
|
|
class zarr_x X
|
|
class numpy_x X
|
|
``` |