feat: update rates regularly (#22)

bin/boltzm

@@ -33,6 +33,10 @@ const { argv } = require('yargs').options({
     describe: 'Port of the boltz-middleware REST API',
     type: 'number',
   },
+  'api.interval': {
+    descibe: 'The interval at which your rates should be updated in minutes',
+    type: 'string',
+  },
   'boltz.host': {
     describe: 'Host of the Boltz gRPC interface',
     type: 'string',

lib/BoltzMiddleware.ts

@@ -26,7 +26,7 @@ class BoltzMiddleware {
     this.db = new Database(this.logger, this.config.dbpath);
     this.boltzClient = new BoltzClient(this.logger, this.config.boltz);
 
-    this.service = new Service(this.logger, this.db, this.boltzClient);
+    this.service = new Service(this.logger, this.db, this.boltzClient, this.config.api.interval);
     this.api = new Api(this.logger, this.config.api, this.service);
   }
 

lib/Config.ts

@@ -37,6 +37,8 @@ class Config {
     this.api = {
       host: '127.0.0.1',
       port: 9001,
+
+      interval: 15,
     };
 
     this.boltz = {

lib/Utils.ts

@@ -22,31 +22,44 @@ export const splitPairId = (pairId: string): { quote: string, base: string } =>
 };
 
 /**
- * Gets the current date in the LocaleString format.
+ * Get the current date in the LocaleString format.
  */
 export const getTsString = (): string => (new Date()).toLocaleString('en-US', { hour12: false });
 
 /**
- * Concats an error code and its prefix
+ * Concat an error code and its prefix
  */
 export const concatErrorCode = (prefix: number, code: number) => {
   return `${prefix}.${code}`;
 };
 
 /**
- * Stringifies any object or array
+ * Stringify any object or array
  */
 export const stringify = (object: any) => {
   return JSON.stringify(object, undefined, 2);
 };
 
 /**
- * Turns a map into an array
+ * Turn a map into an array
  */
 export const mapToArray = (map: Map<any, any>) => {
   return Array.from(map.entries());
 };
 
+/**
+ * Turn a map into an object
+ */
+export const mapToObject = (map: Map<any, any>) => {
+  const object: any = {};
+
+  map.forEach((value, index) => {
+    object[index] = value;
+  });
+
+  return object;
+};
+
 /**
  * Check whether a variable is a non-array object
  */
@@ -56,7 +69,7 @@ export const isObject = (val: any): boolean => {
 
 /**
  * Recursively merge properties from different sources into a target object, overriding any
- * existing properties.
+ * existing properties
  *
  * @param target The destination object to merge into.
  * @param sources The sources objects to copy from.

lib/api/Api.ts

@@ -8,6 +8,8 @@ import Service from '../service/Service';
 type ApiConfig = {
   host: string;
   port: number;
+
+  interval: number;
 };
 
 class Api {

lib/rates/RateProvider.ts

@@ -4,42 +4,54 @@ import { PairInstance } from 'lib/consts/Database';
 import { getPairId, stringify, mapToArray } from '../Utils';
 
 // TODO: add unit tests
+// TODO: make rate update interval configurable
 class RateProvider {
-  private cryptoCompare: CryptoCompare;
+  // A map between pair ids and their rates
+  public rates = new Map<string, number>();
 
-  constructor(private logger: Logger) {
+  // A map between quote and their base assets
+  private baseAssetsMap = new Map<string, string[]>();
+
+  private cryptoCompare = new CryptoCompare();
+
+  constructor(private logger: Logger, private rateUpdateInterval: number) {
     this.cryptoCompare = new CryptoCompare();
   }
 
   /**
    * Gets a map of of rates for the provided pairs
    */
-  public getRates = async (pairs: PairInstance[]) => {
-    // A map between the quote and their base assets
-    const baseAssetsMap = new Map<string, string[]>();
-
+  public init = async (pairs: PairInstance[]) => {
     pairs.forEach((pair) => {
-      const baseAssets = baseAssetsMap.get(pair.quote);
+      const baseAssets = this.baseAssetsMap.get(pair.quote);
 
       if (baseAssets) {
         baseAssets.push(pair.base);
       } else {
-        baseAssetsMap.set(pair.quote, [pair.base]);
+        this.baseAssetsMap.set(pair.quote, [pair.base]);
       }
     });
 
-    this.logger.silly(`Prepared data for requests to CryptoCompare: ${stringify(mapToArray(baseAssetsMap))}`);
+    this.logger.silly(`Prepared data for requests to CryptoCompare: ${stringify(mapToArray(this.baseAssetsMap))}`);
+
+    await this.updateRates();
 
-    const rates = new Map<string, number>();
+    this.logger.silly(`Updating rates every ${this.rateUpdateInterval} minutes`);
 
+    setInterval(async () => {
+      await this.updateRates();
+    }, this.rateUpdateInterval * 60 * 1000);
+  }
+
+  private updateRates = async () => {
     const promises: Promise<any>[] = [];
 
-    baseAssetsMap.forEach((baseAssets, quoteAsset) => {
+    this.baseAssetsMap.forEach((baseAssets, quoteAsset) => {
       promises.push(new Promise(async (resolve) => {
         const baseAssetsRates = await this.cryptoCompare.getPriceMulti(baseAssets, [quoteAsset]);
 
         baseAssets.forEach((baseAsset) => {
-          rates.set(getPairId({ base: baseAsset, quote: quoteAsset }), baseAssetsRates[baseAsset][quoteAsset]);
+          this.rates.set(getPairId({ base: baseAsset, quote: quoteAsset }), baseAssetsRates[baseAsset][quoteAsset]);
         });
 
         resolve();
@@ -48,10 +60,9 @@ class RateProvider {
 
     await Promise.all(promises);
 
-    this.logger.debug(`Got updated rates: ${stringify(mapToArray(rates))}`);
-
-    return rates;
+    this.logger.debug(`Updated rates: ${stringify(mapToArray(this.rates))}`);
   }
+
 }
 
 export default RateProvider;

lib/service/Service.ts

@@ -7,7 +7,7 @@ import { OrderSide, OutputType, CurrencyInfo } from '../proto/boltzrpc_pb';
 import PairRepository from './PairRepository';
 import RateProvider from '../rates/RateProvider';
 import { PairInstance, PairFactory } from '../consts/Database';
-import { splitPairId, stringify, mapToArray } from '../Utils';
+import { splitPairId, stringify, mapToArray, mapToObject } from '../Utils';
 import Errors from './Errors';
 
 type PairConfig = {
@@ -19,8 +19,6 @@ type Pair = {
   id: string;
   base: string;
   quote: string;
-
-  rate: number;
 };
 
 type PendingSwap = {
@@ -43,14 +41,10 @@ class Service extends EventEmitter {
 
   private pairs = new Map<string, Pair>();
 
-  // This object is needed because a stringifyied Map is an empty object
-  // tslint:disable-next-line:no-null-keyword
-  private pairsObject = {};
-
-  constructor(private logger: Logger, db: Database, private boltz: BoltzClient) {
+  constructor(private logger: Logger, db: Database, private boltz: BoltzClient, rateInterval: number) {
     super();
 
-    this.rateProvider = new RateProvider(this.logger);
+    this.rateProvider = new RateProvider(this.logger, rateInterval);
     this.pairRepository = new PairRepository(db.models);
   }
 
@@ -110,24 +104,19 @@ class Service extends EventEmitter {
       }
     };
 
-    const rates = await this.rateProvider.getRates(dbPairs);
+    await this.rateProvider.init(dbPairs);
 
     dbPairs.forEach((pair) => {
       try {
         verifyBackendSupport(pair.base);
         verifyBackendSupport(pair.quote);
 
-        const rate = rates.get(pair.id)!;
-
         this.pairs.set(pair.id, {
           // The values have to be set manually to avoid "TypeError: Converting circular structure to JSON" errors
-          rate,
           id: pair.id,
           base: pair.base,
           quote: pair.quote,
         });
-
-        this.pairsObject[pair.id] = rate;
       } catch (error) {
         this.logger.warn(`Could not initialise pair ${pair.id}: ${error.message}`);
       }
@@ -158,7 +147,7 @@ class Service extends EventEmitter {
    * Gets all supported pairs and their conversion rates
    */
   public getPairs = () => {
-    return this.pairsObject;
+    return mapToObject(this.rateProvider.rates);
   }
 
   /**
@@ -182,12 +171,13 @@ class Service extends EventEmitter {
     const { base, quote } = splitPairId(pairId);
 
     const pair = this.pairs.get(pairId);
+    const rate = this.rateProvider.rates.get(pairId);
 
-    if (pair === undefined) {
+    if (!pair || !rate) {
       throw Errors.PAIR_NOT_SUPPORTED(pairId);
     }
 
-    const swapResponse = await this.boltz.createSwap(base, quote, orderSide, pair.rate, invoice, refundPublicKey, OutputType.COMPATIBILITY);
+    const swapResponse = await this.boltz.createSwap(base, quote, orderSide, rate, invoice, refundPublicKey, OutputType.COMPATIBILITY);
     await this.boltz.listenOnAddress(this.getChainCurrency(orderSide, base, quote), swapResponse.address);
 
     const id = uuidv4();