feat(node): [NET-1455] Autostaker plugin

[teogeb]

Summary

An experimental plugin that automatically manages sponsorship stakings. It periodically checks which sponsorships offer good payouts and stakes tokens to those sponsorships when possible (i.e. if there are unstaked tokens available or tokens can be unstaked from another sponsorship with a worse payout).

Features

• Uses a payout-proportional strategy, see details in the comment of payoutProportionalStrategy.ts
• Simple error handling: if an error occurs during staking or unstaking, all subsequent actions in that run are skipped (this is acceptable because the actions will be retried in the next scheduled run)
• Uses an approximate scheduler
• Operators select different sponsorships if multiple sponsorships have the same payoutPerSec
• Filters out:
  • small transactions (the minimum transaction size is configurable via minTransactionDataTokenAmount)
  • sponsorships with too small payouts
  • sponsorships with a non-zero minimumStakingPeriodSeconds
  • sponsorships that require too many operators to join before payouts start (configurable via maxAcceptableMinOperatorCount)
  • sponsorships that have already reached the maximum number of operator stakes

Authentication

As the plugin does transaction on behalf of the operator, it needs either operator's private key or a CONTROLLER role assigned to it so that it can act as a staking agent. Granting the role is the preferred approach since controllers don't have permission to withdraw funds from the Operator contract

Future Improvements

• Support sponsorships with minimumStakingPeriodSeconds by implementing logic to prevent premature unstaking, instead of filtering them out.
• Convert the smoke test to an integration test and run it in CI. The test is currently quite slow.
• Consider combining the rounding logic and the filtering of small transactions. A possible approach: 1) skip rounding, 2) filter out transactions that are too small, 3) balance the net change by removing or reducing the smallest stakes. This would stake all available tokens but might do too many transactions overall.

[linear]

NET-1455 Autostaker plugin

[harbu]

Two things that need solving still

• Handling of minimumStakingPeriodSeconds. I suggest we just ignore / skip sponsorships that have this set (in the spirit of MVP). Future improvement here is to add support for such sponsorships.
• Handling of minOperatorCount (or whatever the variable is named). I suggest there is a config setting (e.g. maxAcceptableMinOperatorCount) that controls what is the maximum acceptable number for this config for a sponsorship. Any sponsorship requiring a higher amount of operators is simply ignored / skipped.