Crate sp_block_production_log 

Primitives and support crate for pallet_block_production_log.

This crate defines the primitive types and the inherent data provider for the block production log feature.

Usage

This crate supports operation of pallet_block_production_log. Consult the pallet’s documentation on how to include it in the runtime.

Adding to the node

Defining the types

The feature requires two types to be defind by the chain builders in their code:

• Author: the type representing the block author, as it’s configured in the feature’s pallet
• Moment: a moment in time when the block was produced, which carries enough information to calculate the block’s author. Typcally, this type can be a timestamp, or a slot, depending on the consensus mechanism used, but can be a richer type if needed.

Implementing the runtime API

The block production log feature requires BlockProductionLogApi to be implemented by the Partner Chain runtime so the current block author can be identified. The concrete implementation must use or match the mechanism of block author selection used by the particular Partner Chain’s consensus mechanism.

An example for a Partner Chain using Aura consensus looks like this:

impl_runtime_apis! {
    impl BlockProductionLogApi<Block, CommitteeMember, Slot> for Runtime {
        fn get_author(slot: Slot) -> Option<CommitteeMember> {
            SessionCommitteeManagement::get_current_authority_round_robin(u64::from(*slot) as usize)
        }
    }
}

using the pallet_session_committee_management::Pallet::get_current_authority_round_robin function which performs the same round-robin author selection that Aura does internally.

Adding the inherent data provider

The inherent data provider should be added to the node’s CreateInherentDataProviders implementation for both proposal and validation of blocks. eg.:

// Create the inherent data provider. `slot` must be the slot number of the block currently being produced/verified
let block_author_idp = BlockAuthorInherentProvider::new(client.as_ref(), parent_hash, slot)?;
...
// Return the inherent data provider together with other IDPs
Ok((timestamp_idp, slot_idp, ..., block_author_idp, ...))

Notice that the IDP must be passed the current Moment, which in this instance is Slot.

The inherent data provider created using BlockAuthorInherentProvider::new will check whether BlockProductionLogApi is available in the runtime and will only provide inherent data if the API is present.

Structs

BlockAuthorInherentProvider

Inherent data provider providing the block author of the current block Type parameters:

BlockProductionInherentDataV1

Current block producer data used as inherent data

Enums

InherentError

Error type used for failing calls of the block production log feature’s inherent.

Constants

INHERENT_IDENTIFIER

Inherent identifier used by the Block Production Log pallet

Traits

BlockProductionLogApi

Runtime API exposing data required for the BlockAuthorInherentProvider to operate. Type parameters: