How do I get a sample of a Pandas DataFrame to show up in the Dagster UI, Dagit?

[sryza]

Asked on Slack: https://dagster.slack.com/archives/C01U954MEER/p1662064675411779

[sryza]

To do this for a single asset, you can do something like:

@asset
def asset1():
    df = ...
    return Output(value=df, {"df": MetadataValue.md(df.head().to_markdown())})

Alternatively, if many assets that are outputted as dataframes are handled by the same IO manager, you can put the code in the IO manager to have it work across all of them:

class MyIOManager(IOManager):
    def handle_output(self, context, obj)
        ...
        context.add_output_metadata({"df": MetadataValue.md(obj.head().to_markdown())})