Karaoke

For this exercise you may use substrate-node-template application.

Implement:

• a new inherent data provider that puts a new line of song to an every block,

• a new karaoke pallet that reads every song line from a block's inherents and emits an event that contains the line.

Relevant substrate parts:

• pallet timestamp as an inspiration for how to read block's inherents,

• pallet template as a baseline for the solution,

• runtime template - here all the chosen pallets are combined to form a runtime of the blockchain,

• node template - here all the blockchain functionalities are initialized and run.

Implementation hints:

• Implement custom InherentDataProvider that proposes song lines. Use it in the aura block provider in service.rs,

• implement a new pallet and implement ProvideInherent trait for it that takes a new line from the block and puts it into the blockchain storage, and then emits and event. Add this pallet to the runtime.

Note: prior to Substrate v4, it was only possible to do this task via implementing a wrapper for Proposer and ProposerFactory that puts a line of song to InherentData and use sc_basic_authorship::Proposer and sc_basic_authorship::ProposerFactory respectively to generate a block proposition, followed by using this wrapper instead of sc_basic_authorship::ProposerFactory in bin/node-template/node/src/service.