Manage Validators in a Contract

[heikoheiko]

Currently the list of validators is managed in the configuration.

Task:

• Write a smart contract that keeps track of the validators
• Write an abstraction to retrieve the list of validators

Contract:
Stores

• validators = Map(validator_address : (begin_block, end_block))
  while last_block can be zero if validation does not expire
• proposals = Map(validator_address : (begin_block, end_block, voting_end_block))
• proposal_votes Map(validator_address : [votes])

Logic:
The contract is consulted to get the list of validators for a certain block height.
New validators are proposed by anyone and voted on by the current set of validators. Validators are removed by proposing them with an end_block in the past. With every vote transaction the quorum (another contract member, settable as a fraction of the number of validators) is checked and if reached the validator is added/removed to the validator list. Also with every tx pending proposals are checked for voting_end_block.

Notes:

• think about caching access to the validator set in the contract, since there are many requests to the validator set and looking it up in the contract is slow.