[Documentation Feedback] Needing more documentation on custom type handlers.

[CelianInfo]

The last example of this page show a custom IO manager that can handle multiple types by defining a static function named "type_handlers" that returns a list of type handler object.

But we lack in the documentation how we correctly define a type handler class. We don't know if we should use inheritance from a base class, use isinstance() or not.

We might raise an error when our type handler encounter the wrong type of data, but we don't know if raising an error with make our IO manager switch to the next type handler or simply fail.

A simple example of type handler is needed. I don't think it is really complicated and it will help greatly.

[garethbrickman]

Could you share the link to the page you mean?

[CelianInfo]

The screenshot I made is the last example of the following page : https://docs.dagster.io/integrations/duckdb/reference

To further explain what I'm looking for here is exactly what I need :

On this documentation page (dagster-duckdb library), we have in the first example the following code :

class MyDuckDBIOManager(DuckDBIOManager):
    @staticmethod
    def type_handlers() -> Sequence[DbTypeHandler]:
        return [DuckDBPandasTypeHandler()]

We don't have anywhere in the documentation the type DbTypeHandler. I would like to know how to define a DbTypeHandler. It is currently missing inside the documentation and is quite troublesome for my use case.

I need my IO manager to handle the returned asset, selecting the right logic depending on the returned object's type, at runtime.

There are multiples DbTypeHandler that dagster offer, in our case the example use DuckDBPandasTypeHandler().
Since dagster use DbTypeHandler on multiple occasions, is there documentation already made that cover this topic that you could share ?