Proof of Yield - Pre-Dripper accounting backend

[franckc]

Requirements doc

[micahalcorn]

Latest design: https://www.figma.com/file/eN26ytHYvZ7bhCaHy5K0iv/OUSD-Proof-of-Yield?node-id=233%3A22895&t=ePHblOSpt4C6ExIt-4

The doc linked above is rather long-winded, so here's a summary of what I think we're going to want.

• First, it's worth noting that some yield is pre-Dripper (e.g. harvests) and other yield is neither pre-Dripper nor post-Dripper (e.g. lending interest). Even after we start fully utilizing the Dripper for 100% of yield, there will be historical data involving non-Dripper yield. We want to account for all of it. The important distinction here is that, for yield that does go through the Dripper, we don't need to trace it from rebase back to its original yield source(s). Dripper is almost like a mixer that complicates the mapping of yield generation to yield distribution. We don't need to know which yield sources were responsible for the latest rebase, but we do want to know which yield sources were responsible for the latest harvest, interest, fees, etc.
• We want a variety of data for a given "time period". It would be nice to support periods as short as just the latest block and as long as everything since the relaunch in January 2021. I'm not sure whether a time period should be defined as beginning and ending block numbers or timestamps. We have agreed that there should be a standard "day" as far as the front-end is concerned, which should either be UTC or correspond to the Keeper rebase schedule.
• It's unclear at this point whether data for "December 31, 2022" means a snapshot as of the end of that day or a weighted average over that 24-hour period. For example, the total supply of OUSD could easily change from 45M early in the day to 50M later in the day. Similarly, the rate earned on Compound DAI could change from 1% to 2% throughout the day. If it's feasible, I believe that a time-weighted average of each data point would be the most meaningful.

Inventory of data

Post-Dripper (very straightforward)

• Total yield distributed
• Total fees collected
• APY
• Total supply
• Pre-boosted APY
• Multiplier
• Non-rebasing supply
• Rebasing supply
• Details for each rebase

Pre-Dripper and Non-Dripper (for each yield source)

• APY (for strategies)
• Yield amount generated (all sources)
• Percent contribution to yield generated

[sparrowDom]

To consolidate notes from the meeting doc here:

• Chainlink can perform upkeep somewhere between windowStart: 25165 and windowEnd: 26065 periods. Those are UTC seconds in a day. A couple of minutes after the windowEnd will be selected as a new day has begun marker. Ensuring that the rebase event happens somewhere at the end of the day
• We will implement 2 ways of accounting for pre dripper yield reward tokens:
  • Take current strategy reward token emission and current reward token price and simulate to the best of our ability what actual yield will be with the future harvest event
  • Do the exact account at the time of reward token harvest. Correcting all the estimated APYs in the daily snapshots
• Strategies can have varying amount of funds in them within the same harvest interval. When accounting for yield reward tokens need to be accounted for according to the amount of funds in the strategy at any time.