How to customize block header structure

[JackPiri]

Hi,
I come from great Cosmos-SDK experience, where transactions/messages customization is made available using ignite cli; what you have to do is just leveraging command scaffold, then some auto-generated code is made available and you just have to add your custom validations, logics and interactions. In this way you don't need to fork from Cosmos-SDK codebase, with obvious maintenance benefits.

Now the questions are: is there a similar scaffolding feature for cometbft? in particular, is it possible to customize the block header structure (type Header struct in block.go) without forking from cometbft codebase? is there any good tutorial available for a step-by-step experience?

Thanks a lot!

[melekes]

in particular, is it possible to customize the block header structure (type Header struct in block.go) without forking from cometbft codebase?

Unfortunately, this is not possible with the current implementation. The structure of the Header is fixed.

However, you can attach an event (or a list of events) to each block or even an individual transaction - https://docs.cometbft.com/v0.37/app-dev/indexing-transactions (spec: https://github.com/cometbft/cometbft/blob/v0.37.x/spec/abci/abci++_basic_concepts.md#events). These can later be used to query blocks/transactions via RPC. You can also have a special transaction in your application (see #448 (comment)). Also, votes can be extended with arbitrary information (https://github.com/cometbft/cometbft/blob/v0.37.x/spec/abci/abci%2B%2B_methods.md#extendedvoteinfo). While none of these methods provide complete control over Header structure, it's still possible to implement some custom use-cases.

Does that work for you? Could you describe what you're trying to do?