Add SDR calculation

feeder/Dockerfile

@@ -10,6 +10,8 @@ ENV ORACLE_FEEDER_KEY_PATH=voter.json
 ENV ORACLE_FEEDER_COIN_TYPE=330
 ENV ORACLE_FEEDER_ADDR_PREFIX=terra
 
+ENV ORACLE_SDR_BASKET=USD:0.57813,EUR:0.37379,JPY:13.452,CNY:1.0993,GBP:0.080870
+
 WORKDIR /app
 
 COPY package*.json ./

feeder/src/index.ts

@@ -64,6 +64,12 @@ function registerCommands(parser: ArgumentParser): void {
     defaultValue: `voter`,
   })
 
+  voteCommand.addArgument(['-s', '--sdr-basket'], {
+    help: `SDR basket information`,
+    dest: `sdrBasket`,
+    defaultValue: '',
+  })
+
   // Updating Key command
   const keyCommand = subparsers.addParser(`add-key`, { addHelp: true })
 
@@ -123,6 +129,16 @@ async function main(): Promise<void> {
       args.validators || (process.env.ORACLE_FEEDER_VALIDATORS && process.env.ORACLE_FEEDER_VALIDATORS.split(','))
     args.keyName = process.env.ORACLE_FEEDER_KEY_NAME ? process.env.ORACLE_FEEDER_KEY_NAME : args.keyName
 
+    args.sdrBasket = args.sdrBasket || process.env.ORACLE_SDR_BASKET || ''
+    // convert basket data into json object
+    if (args.sdrBasket !== '') {
+      args.sdrBasket = args.sdrBasket.split(',').reduce((acc: { string: string }, curr: string) => {
+        const [key, value] = curr.split(':')
+        acc[key] = value
+        return acc
+      }, {})
+    }
+
     await vote(args)
   } else if (args.subparser_name === `add-key`) {
     await addKey(args.keyPath, args.coinType, args.keyName)

feeder/src/vote.ts

@@ -74,7 +74,49 @@ interface Price {
   price: string
 }
 
-async function getPrices(sources: string[]): Promise<Price[]> {
+function calculateSDR(prices: Price[], sdrBasket: string): Price | undefined {
+  if (!sdrBasket) {
+    return undefined
+  }
+
+  // check if all prices from the basket are available
+  for (const denom of Object.keys(sdrBasket)) {
+    if (denom === 'USD') {
+      continue
+    }
+    if (!prices.find((p) => p.denom === denom)) {
+      logger.error(`getPrices: price for ${denom} not found`)
+      return undefined
+    }
+  }
+
+  // calculate SDR price
+  let sdrPrice: BigNumber | undefined = undefined
+
+  try {
+    sdrPrice = Object.entries(sdrBasket).reduce((acc, [denom, weight]) => {
+      const price = denom === 'USD' ? { price: '1.0' } : prices.find((p) => p.denom === denom)
+      if (!price) {
+        throw new Error(`price for ${denom} not found`)
+      }
+      return acc.plus(new BigNumber(price.price).times(weight))
+    }, new BigNumber(0))
+  } catch (err) {
+    logger.error(`getPrices: error calculating SDR price: ${err.message}`)
+    return undefined
+  }
+
+  if (!sdrPrice) {
+    return undefined
+  }
+
+  return {
+    denom: 'SDR',
+    price: sdrPrice.toString(),
+  }
+}
+
+async function getPrices(sources: string[], sdrBasket: string): Promise<Price[]> {
   const results = await Bluebird.some(
     sources.map((s) => ax.get(s)),
     1
@@ -99,6 +141,18 @@ async function getPrices(sources: string[]): Promise<Price[]> {
     return []
   }
 
+  if (results[0].data.prices.find((p) => p.denom === 'SDR')) {
+    logger.info(`[VOTE] SDR price found from price server`)
+    return results[0].data.prices
+  }
+
+  const sdr = calculateSDR(results[0].data.prices, sdrBasket)
+  logger.info(`[VOTE] SDR price: ${sdr?.price}`)
+
+  if (sdr) {
+    results[0].data.prices.push(sdr)
+  }
+
   return results[0].data.prices
 }
 
@@ -189,7 +243,7 @@ export async function processVote(
 
   // Print timestamp before start
   logger.info(`[VOTE] Requesting prices from price server ${args.dataSourceUrl.join(',')}`)
-  const _prices = await getPrices(args.dataSourceUrl)
+  const _prices = await getPrices(args.dataSourceUrl, args.sdrBasket)
 
   // Removes non-whitelisted currencies and abstain for not fetched currencies
   const prices = preparePrices(_prices, oracleWhitelist)
@@ -302,6 +356,7 @@ interface VoteArgs {
   password: string
   keyPath: string
   keyName: string
+  sdrBasket: string
 }
 
 function buildLCDClientConfig(args: VoteArgs, lcdIndex: number): Record<string, LCDClientConfig> {