Investigate & fix bug: Gas data is not available on "mainnet" network

[florianstoecker]

Goal
Know where the bug came from & have it fixed.

Context
This Sunday at around 2pm, I got a Twitter notification that an auction has started. After visiting auctions.makerdao.com/collateral, an error was shown in the auctions table (See assets for screenshot of the auctions table & console message). I've tested it out on mobile & computer. The error was shown on both devices for me.

Re-visiting the page after some time, the error disappeared for me.

Tasks

• Investigate the error & document your findings here.
• Fix the error.

Assets

[valiafetisov]

The issue is obviously thrown at getGasPrice:

unified-auctions-ui/core/src/gas.ts

Lines 23 to 33 in bb2c0a4

	export const getGasPrice = async function (network: string): Promise<BigNumber> {
	const networkConfig = getNetworkConfigByType(network);
	if (networkConfig.gasPrice) {
	return new BigNumber(networkConfig.gasPrice).shiftedBy(-ETH_NUMBER_OF_DIGITS);
	}
	try {
	return await getCurrentGasPrice();
	} catch (error) {
	throw new Error(`Gas data is not available on "${network}" network`);
	}
	};

And we use getGasPrice when calculating auction fees.

Since we expect that gas price endpoint can be down (and it is periodically down, since it's a free service), we should not depend the whole website on it. What we can do:

• A fallback to some other endpoint if the first one is down
• B fallback to provider.getGasPrice() https://docs.ethers.io/v5/api/providers/provider/#Provider-getGasPrice (but we need fast gas price, not just average from the latest block)
• C don't throw an error and handle fees unknown state
• D calculate out own average gas price https://stackoverflow.com/a/67668790 (unlikely till we have database to store average)

I think a combination of B + C or A + B + C would be good.