FABN-1014: Use ChannelEventHub.connect callback

In EventHubFactory, use the callback parameter to ChannelEventHub.connect
to wrap it as an async function and await the connect completion, rather
than listen for block events to identify when a connect has completed.

Change-Id: I42f1c562a35b04c38919e2317850085ff39385bc
Signed-off-by: Mark S. Lewis <mark_lewis@uk.ibm.com>

fabric-network/lib/impl/event/eventhubfactory.js

@@ -6,6 +6,8 @@
 
 'use strict';
 
+const util = require('util');
+
 const logger = require('fabric-network/lib/logger').getLogger('EventHubFactory');
 
 /**
@@ -67,22 +69,14 @@ class EventHubFactory {
      * @param {ChannelEventHub} eventHub An event hub.
      */
 	async connectEventHub(eventHub) {
-		const connectPromise = new Promise((resolve) => {
-			const regId = eventHub.registerBlockEvent(
-				() => {
-					logger.debug('connectEventHub:', 'successfully connected event hub:', eventHub.getName());
-					eventHub.unregisterBlockEvent(regId);
-					resolve();
-				},
-				() => {
-					logger.info('connectEventHub:', 'failed to connect event hub:', eventHub.getName());
-					eventHub.unregisterBlockEvent(regId);
-					resolve();
-				}
-			);
-		});
-		eventHub.connect();
-		await connectPromise;
+		try {
+			// Need to wrap in an arrow function to protect the value of this in connect()
+			const connect = util.promisify((callback) => eventHub.connect({}, callback));
+			await connect();
+			logger.debug('connectEventHub:', 'successfully connected event hub:', eventHub.getName());
+		} catch (error) {
+			logger.info('connectEventHub:', 'failed to connect event hub:', eventHub.getName(), error);
+		}
 	}
 }
 

fabric-network/test/impl/event/eventhubfactory.js

@@ -48,13 +48,16 @@ describe('EventHubFactory', () => {
 		stubEventHub2 = sinon.createStubInstance(ChannelEventHub);
 		stubEventHub2._stubInfo = 'eventHub2';
 		stubEventHub2.getName.returns('eventHub2');
-		// Fake a connection success event
-		stubEventHub2.registerBlockEvent.callsFake((block, error) => { // eslint-disable-line no-unused-vars
-			Promise.resolve().then(block);
-			return 2;
-		});
 		stubEventHub2.isconnected.returns(false);
-
+		// Fake a connection success callback
+		stubEventHub2.connect.callsFake((fullBlocks, callback) => {
+			// Invoke callback manually rather than using stub.callsArgWith() to ensure the code will hang rather than
+			// error if the callback is not passed correctly. An error will be swallowed by the code in EventHubFactory
+			// and produce a false positive test result.
+			if (typeof callback === 'function') {
+				callback(null, stubEventHub2);
+			}
+		});
 		stubChannel = sinon.createStubInstance(Channel);
 		stubChannel.getName.returns('channel');
 		stubChannel.getChannelEventHub.withArgs(stubPeer1.getName()).returns(stubEventHub1);
@@ -108,10 +111,11 @@ describe('EventHubFactory', () => {
 		});
 
 		it('does not fail on error connecting event hub', async () => {
-			// Fake a connection failure event
-			stubEventHub2.registerBlockEvent.callsFake((block, error) => {
-				Promise.resolve().then(error);
-				return 2;
+			// Fake a connection failure callback
+			stubEventHub2.connect.callsFake((fullBlocks, callback) => {
+				if (typeof callback === 'function') {
+					callback(new Error('connect failed'));
+				}
 			});
 			const results = await factory.getEventHubs([stubPeer2]);
 			expect(results[0].connect.called).to.be.true;