Hey folks, is it possible to

pulumi import

a resource from custom provider?

As long as the provider implements the Read method yes

Great, thanks. In this definition, what is contained in the input map argument:

Read func(context.Context, map[string]interface{}) (map[string]interface{}, bool, error)

Is there a way for me to pass some args/data when running

pulumi import yyy

to the Read function?

if your importing the input map argument will be empty. Read is also used for refresh in which case the map will contain the inputs the engine currently knows about. The only information import will pass to Read is ID. Some providers encode properties as part of the ID as a way to pass information.