add EURS on Stellar, and some Stellar-specific helper functions

src/adapters/peggedAssets/helper/stellar.ts

@@ -0,0 +1,24 @@
+const axios = require("axios");
+const retry = require("async-retry");
+
+const stellarExpertEndpoint = (assetCode: string, assetIssuer: string): string =>
+  `https://api.stellar.expert/explorer/public/asset/${assetCode}-${assetIssuer}`;
+
+export async function getAsset(assetID: string) {
+  // assetID is concatenation of the assetCode and assetIssuer, separated by a colon
+  const [assetCode, assetIssuer] = assetID.split(":");
+  const asset = await retry(
+    async (_bail: any) =>
+      await axios.get(stellarExpertEndpoint(assetCode, assetIssuer))
+  );
+  const data = asset.data;
+  return data;
+}
+
+export async function getTotalSupply(assetID: string) {
+  // assetID is concatenation of the assetCode and assetIssuer, separated by a colon
+  const asset = await getAsset(assetID);
+  const decimals = 7;
+  const supply = asset?.supply;
+  return supply / 10 ** decimals;
+}

src/adapters/peggedAssets/stasis-eurs/index.ts

@@ -10,6 +10,7 @@ import {
   PeggedIssuanceAdapter,
   Balances,  ChainContracts,
 } from "../peggedAsset.type";
+import * as stellar from "../helper/stellar";
 const axios = require("axios");
 const retry = require("async-retry");
 
@@ -152,6 +153,19 @@ async function algorandMinted() {
   };
 }
 
+async function stellarMinted() {
+  return async function (
+    _timestamp: number,
+    _ethBlock: number,
+    _chainBlocks: ChainBlocks
+  ) {
+    let balances = {} as Balances;
+    const supply = await stellar.getTotalSupply("EURS:GC5FGCDEOGOGSNWCCNKS3OMEVDHTE3Q5A5FEQWQKV3AXA7N6KDQ2CUZJ")
+    sumSingleBalance(balances, "peggedEUR", supply, "issued", false)
+    return balances;
+  }
+}
+
 const adapter: PeggedIssuanceAdapter = {
   ethereum: {
     minted: chainMinted("ethereum", 2),
@@ -191,6 +205,9 @@ const adapter: PeggedIssuanceAdapter = {
       "peggedEUR"
     ),
   },
+  stellar: {
+    minted: stellarMinted(),
+  },
 };
 
 export default adapter;