chore: add a method for getting latest round if for a given price feed

Agoric#182

packages/synthetic-chain/src/lib/econHelpers.js

@@ -1,6 +1,12 @@
 import { executeOffer, waitForBlock } from './commonUpgradeHelpers.js';
 import { ATOM_DENOM, CHAINID, VALIDATORADDR } from './constants.js';
-import { agd, agops, executeCommand, agopsLocation } from './cliHelper.js';
+import {
+  agd,
+  agops,
+  executeCommand,
+  agopsLocation,
+  agoric as agoricAmbient,
+} from './cliHelper.js';
 import { GOV1ADDR, GOV2ADDR, GOV3ADDR } from './constants.js';
 import { queryVstorage, getQuoteBody, getInstanceBoardId } from './vstorage.js';
 
@@ -198,6 +204,16 @@ export const pushPrices = async (price, brandIn, oraclesByBrand, round) => {
   }
 };
 
+export const getRoundId = async (price, io = {}) => {
+  const {
+    agoric = { follow: agoricAmbient.follow },
+    prefix = 'published.',
+  } = io;
+  const path = `:${prefix}priceFeed.${price}-USD_price_feed.latestRound`;
+  const round = await agoric.follow('-lF', path);
+  return parseInt(round.roundId);
+};
+
 export const getPriceQuote = async price => {
   const path = `published.priceFeed.${price}-USD_price_feed`;
   const body = await getQuoteBody(path);

packages/synthetic-chain/test/snapshots/test-exports.ts.md

@@ -68,6 +68,7 @@ Generated by [AVA](https://avajs.dev).
       getPriceQuote: AsyncFunction {},
       getProvisionPoolMetrics: AsyncFunction [],
       getQuoteBody: AsyncFunction {},
+      getRoundId: AsyncFunction {},
       getUser: AsyncFunction {},
       getVatDetails: AsyncFunction {},
       getVaultPrices: AsyncFunction {},