Derive Macro WithOptions

#[derive(WithOptions)]
{
    // Attributes available to this derive:
    #[with_option]
}

Annotates that the struct represents the WITH properties for a connector. This implements a marker trait WithOptions. It’s also used to generate the with_option_*.yaml files.

Notes about how to define property structs

Prefer strongly-typed fields

Avoid using HashMap with #[serde(flatten)] to include all unknown fields. Declare all fields explicitly instead.

The only exception now is CDC, which needs to pass a lot of options as-is to Debezium.

Common struct

When there are some fields can be grouped together, and/or can be shared by source and sink, or by multiple connectors, define a struct for them and use the common struct as a #[serde(flatten)] field.

Add #[derive(WithOptions)] to both the outer and the inner struct.

Avoid using nested #[serde(flatten)] field in the common struct, because this will lead to unexpected serde behaviors. Put all flatten fields in the top-level struct instead.