Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
import Web3 from "web3";
import Knex from "knex";
import {
loadTokenList,
marketContract,
borrowAndSupplyRate,
rateToApy
} from "./compound.js";
import { subscribeNewBlocks } from "../libs/eth.js";
import config from "../config.js";
// initialize
const web3 = new Web3(`wss://mainnet.infura.io/ws/v3/${config.dev.PROJECT_ID}`);
const knex = Knex(config.dev.db);
// effect
let tokenList;
loadTokenList()
.then(tl => (tokenList = tl))
.catch(err => {
throw err;
});
// subscription
const subscription = subscribeNewBlocks(web3, async (err, blockHeader) => {
// error handling
if (err !== null) {
// TODO push blockNumber onto error queue and retry at a later time
console.error(err);
return;
}
console.log(blockHeader);
const projectName = "compound";
// error handling
// hack. Just skip if tokenList hasn't been loaded yet
if (tokenList === null) {
console.warn(
`token list not yet loaded...skipping block ${blockHeader.number}`
);
return;
}
/*
* written in this style, we assume that we need borrowAndSupplyRate
* to all respond before moving on. There's no data dependency between
* the different tokens, so we shouldn't have to do that.
*
* also, by using Promise.all, if one fails, they all fail.
*/
const tokenApys = await Promise.all(
tokenList.tokens
// filter
.filter(tokenRecord => tokenRecord.chainId === 1)
// filter
.filter(tokenRecord => tokenRecord.symbol.match(/c.*/))
// map effects
.map(async tokenRecord => {
// effect
// FIXME this is I/O what happens to other tokens if one fetch fails?
const rates = await borrowAndSupplyRate(web3, tokenRecord.symbol);
return {
market_name: tokenRecord.symbol,
borrow_rate: rates.borrowRate,
supply_rate: rates.supplyRate
};
})
);
// map effect
// This is just for printing. Do no processing in ingestion
tokenApys.map(tokenApy => {
const borrowApy = rateToApy(tokenApy.borrow_rate); // pure function
const supplyApy = rateToApy(tokenApy.supply_rate); // pure function
const marketName = tokenApy.market_name;
console.log(
`${marketName}: Supply APY = ${supplyApy.toFormat(
18
)}%, Borrow APY = ${borrowApy.toFormat(18)}%`
);
});
// map pure
// transform to data we want to persist
// meader mapping?
const apyRecords = tokenApys.map(data => {
return {
blocknumber: blockHeader.number,
project_name: projectName,
data,
block_at: new Date(blockHeader.timestamp * 1000),
created_at: new Date(),
updated_at: new Date()
};
});
// persist in source db
// map effects
await Promise.all(
apyRecords.map(apyRecord => {
// effect
return knex("annual_percentage_yields")
.insert(apyRecord)
.catch(err => {
// TODO push blockNumber onto error queue and retry at a later time
console.error(err);
});
})
);
console.log("-----");
});
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment