feat(raiden): channel balance by currency

This modifies the logic around querying raiden for channel balances.
Rather than summing up all balances across all tokens, it allows for
specifying a currency and retrieving only the balance for that
currency. Calling `ChannelBalance` without specifying a currency will
return each currency separately.

It also scales the balance returned by raiden to satoshis (10^-8). This
is because the default units of 10^-18 for currencies such as WETH can
exceed the maximum value of a `uint64` used by the gRPC layer.

Closes #1051.

lib/raidenclient/RaidenClient.ts

@@ -41,6 +41,12 @@ class RaidenClient extends SwapClient {
   private host: string;
   private disable: boolean;
 
+  // TODO: Populate the mapping from the database (Currency.decimalPlaces).
+  private static readonly UNITS_PER_CURRENCY: { [key: string]: number } = {
+    WETH: 10 ** 10,
+    DAI: 10 ** 10,
+  };
+
   /**
    * Creates a raiden client.
    */
@@ -272,14 +278,18 @@ class RaidenClient extends SwapClient {
   }
 
   /**
-   * Returns the total balance available across all channels.
+   * Returns the total balance available across all channels for a specified currency.
    */
-  public channelBalance = async (): Promise<ChannelBalance> => {
-    // TODO: refine logic to determine balance per token rather than all combined
-    const channels = await this.getChannels();
+  public channelBalance = async (currency?: string): Promise<ChannelBalance> => {
+    if (!currency) {
+      return { balance: 0, pendingOpenBalance: 0 };
+    }
+
+    const channels = await this.getChannels(this.tokenAddresses.get(currency));
     const balance = channels.filter(channel => channel.state === 'opened')
       .map(channel => channel.balance)
-      .reduce((acc, sum) => sum + acc, 0);
+      .reduce((sum, acc) => sum + acc, 0)
+      / (RaidenClient.UNITS_PER_CURRENCY[currency] || 1);
     return { balance, pendingOpenBalance: 0 };
   }
 

lib/service/Service.ts

@@ -119,23 +119,27 @@ class Service {
   public channelBalance = async (args: { currency: string }) => {
     const { currency } = args;
     const balances = new Map<string, { balance: number, pendingOpenBalance: number }>();
-    const getBalance = async (currency: string) => {
+
+    if (currency) {
+      argChecks.VALID_CURRENCY(args);
+
       const swapClient = this.swapClientManager.get(currency.toUpperCase());
       if (swapClient) {
-        const channelBalance = await swapClient.channelBalance();
-        return channelBalance;
+        const channelBalance = await swapClient.channelBalance(currency);
+        balances.set(currency, channelBalance);
       } else {
         throw swapsErrors.SWAP_CLIENT_NOT_FOUND(currency);
       }
-    };
-
-    if (currency) {
-      argChecks.VALID_CURRENCY(args);
-      balances.set(currency, await getBalance(currency));
     } else {
-      for (const currency of this.orderBook.currencies) {
-        balances.set(currency, await getBalance(currency));
-      }
+      const balancePromises: Promise<any>[] = [];
+      this.swapClientManager.swapClients.forEach((swapClient, currency) => {
+        if (swapClient.isConnected()) {
+          balancePromises.push(swapClient.channelBalance(currency).then((channelBalance) => {
+            balances.set(currency, channelBalance);
+          }));
+        }
+      });
+      await Promise.all(balancePromises);
     }
 
     return balances;

lib/swaps/SwapClient.ts

@@ -44,8 +44,10 @@ abstract class SwapClient extends EventEmitter {
 
   /**
    * Returns the total balance available across all channels.
+   * @param currency the currency whose balance to query for, otherwise all/any
+   * currencies supported by this client are included in the balance.
    */
-  public abstract channelBalance(): Promise<ChannelBalance>;
+  public abstract channelBalance(currency?: string): Promise<ChannelBalance>;
 
   protected setStatus = async (status: ClientStatus): Promise<void> => {
     this.logger.info(`${this.constructor.name} status: ${ClientStatus[status]}`);

test/jest/RaidenClient.spec.ts

@@ -16,6 +16,45 @@ const getValidTokenPaymentResponse = () => {
   };
 };
 
+const channelBalance1 = 25000000;
+const channelBalance2 = 5000000;
+const channelBalanceTokenAddress = '0xEA674fdDe714fd979de3EdF0F56AA9716B898ec8';
+const getChannelsResponse = [
+  {
+    token_network_identifier: '0xE5637F0103794C7e05469A9964E4563089a5E6f2',
+    channel_identifier: 1,
+    partner_address: '0x61C808D82A3Ac53231750daDc13c777b59310bD9',
+    token_address: channelBalanceTokenAddress,
+    balance: channelBalance1,
+    total_deposit: 35000000,
+    state: 'opened',
+    settle_timeout: 100,
+    reveal_timeout: 30,
+  },
+  {
+    token_network_identifier: '0xE5637F0103794C7e05469A9964E4563089a5E6f2',
+    channel_identifier: 2,
+    partner_address: '0x2A4722462bb06511b036F00C7EbF938B2377F446',
+    token_address: channelBalanceTokenAddress,
+    balance: channelBalance2,
+    total_deposit: 35000000,
+    state: 'opened',
+    settle_timeout: 100,
+    reveal_timeout: 30,
+  },
+  {
+    token_network_identifier: '0xE5637F0103794C7e05469A9964E4563089a5E6f2',
+    channel_identifier: 3,
+    partner_address: '0x3b1c3C1568C848b3C12c88e2aF5E5CAa0b62071A',
+    token_address: channelBalanceTokenAddress,
+    balance: 1000000,
+    total_deposit: 35000000,
+    state: 'closed',
+    settle_timeout: 100,
+    reveal_timeout: 30,
+  },
+];
+
 const getValidDeal = () => {
   return {
     proposedQuantity: 10000,
@@ -91,4 +130,12 @@ describe('RaidenClient', () => {
       .rejects.toMatchSnapshot();
   });
 
+  test('channelBalance calculates the total balance of open channels for a currency', async () => {
+    raiden = new RaidenClient(config, raidenLogger);
+    await raiden.init();
+    raiden.tokenAddresses.get = jest.fn().mockReturnValue(channelBalanceTokenAddress);
+    raiden['getChannels'] = jest.fn()
+        .mockReturnValue(Promise.resolve(getChannelsResponse));
+    await expect(raiden.channelBalance('ABC')).resolves.toHaveProperty('balance', channelBalance1 + channelBalance2);
+  });
 });