Bootstrap the JSON/RPC interface

[peterbroadhurst]

A natural API surface area for Paladin that is natural for Etherum users is JSON/RPC.

• Synchronous RPC for requests such as:
  • Submitting a new transaction to the off-chain mempool / distributed TX manager
  • Querying the status of a transaction
  • Requesting cancellation of a transaction
  • Issuing a state query
• Streaming requests such as:
  • Processing events from smart contracts

However, the Ethereum specific (eth_ / net_) methods that are exposed by Besu and other EVM derivations do not support private transactions.

So we need to create:

• Runtime endpoint(s) for handling JSON/RPC in Paladin over HTTPS & WebSockets
• A new set of ptx_ (or similar) JSON/RPC methods that allow Paladin private transaction management

[peterbroadhurst]

There are multiple hardened implementations of JSON/RPC servers available for us to extend. We have the choice of Golang and Java within our runtime engine.

I did some exploration of the Hyperledger Besu JSON/RPC framework, as we are very closely aligned with that community (embedding key code modules like the Besu EVM). However, the JSON/RPC framework in Besu is not intended for re-use as some other components are - with a tightly coupled view of the set of implemented JSON/RPC methods.

So I've eliminated that as a potential direction.