Aave

https://docs.aave.com/developers/developing-on-aave/the-protocol/price-oracle
https://github.com/aave/aave-protocol/blob/master/contracts/misc/ChainlinkProxyPriceProvider.sol

MCDEX

https://github.com/mcdexio/mai-protocol-v2/blob/2fcbf4b44f4595e5879ff5efea4e42c529ef0ce1/contracts/oracle/ChainlinkAdapter.sol

This Band Protocol integration may also be worth checkin out:
https://github.com/FinNexus/chainLinkBridge/tree/master/contracts

from dev.

@cvalkan are you going to implement one of these, or will we make a design doc first?

from dev.

I've gone through all projects listed on https://feeds.chain.link that are using ChainLink's ETH:USD, and I only found Aave to be using a fallback solution, but only for complete outages as it seems (where price = 0).

According to page 4 of this whitepaper, Lien Protocol is using a proper fallback mechanism, but the project seems to be closed source .

I fear that we won't be able to use/copy any existing fallback solution.

from dev.

There's a line I liked from mai, but I'm not sure what AAVE is doing.
https://liquity.slack.com/archives/CR0CYAUBD/p1606522241108900

from dev.

It seems that at some point AAVE was using Uniswap v1 as its main oracle and Chainlink as a fallback (at least on Kovan):

ConsenSys Diligence audited the code and had some criticism: https://consensys.net/diligence/audits/2020/05/aave-cpm-price-provider/

from dev.

ConsenSys Diligence audited the code and had some criticism: https://consensys.net/diligence/audits/2020/05/aave-cpm-price-provider/

"detects manipulation by comparing the price derived from the state of the Uniswap exchange to the price provided by the Chainlink oracle. If the prices differ significantly, the Chainlink price is taken as correct..."

"In the case that Uniswap is more current than Chainlink, the error margin would be limited to the size of the price change in real world markets..." not sure what they mean here

from dev.