asynchronously fetch token data

[bh2smith]

The previous implementation was naive and this one is much much faster!

closes #868 (Note that it was suggested to use web3-BatchRequest, but this is efficient as is and the web3 option seems to require passing around additional artifacts).

Test Plan
Can't really be tested without a wrapper script. The only script using this within the project is scripts/ensure_owl_liquidity.ts

[fedgiac]

Looks good!

This would be a perfect candidate to test out batch web3 requests at some point.

[bh2smith]

This would be a perfect candidate to test out batch web3 requests at some point.

Yes! I had forgotten. Maybe I should do that now!

[fleupold]

The previous implementation was naive and this one is much much faster!

Would be awesome to quantify how much faster - maybe just using the unix time tool before and after to get an idea.

[bh2smith]

@fleupold

This would be a perfect candidate to test out batch web3 requests at some point.

Old Script:
Fetching info for 18 tokens
Execution Time: 66.557 seconds

New Script:
Fetching info for 18 tokens
Execution Time: 3.478 seconds

Appears to be about 22x faster.

This was executed with the following script:

import { fetchTokenInfoFromExchange } from "../src/fee_token_liquidity";
import { getBatchExchange } from "./util";

module.exports = async (callback: Truffle.ScriptCallback) => {
  try {
    const exchange = await getBatchExchange(artifacts);
    const numTokens = (await exchange.numTokens()).toNumber();
    const tokens = Array(numTokens)
      .fill(0)
      .map((_, i) => i);
    console.log(`Fetching info for ${numTokens} tokens`);
    console.time("Execution Time");
    await fetchTokenInfoFromExchange(exchange, tokens, artifacts);
    console.timeEnd("Execution Time");
    callback();
  } catch (error) {
    callback(error);
  }
};

using

npx truffle exec build/common/scripts/test_script.js --network rinkeby

[fleupold]

Awesome speed improvement!