Fix issue with Live Metrics Initialization (#1216)

Author: hectorhdzg

Tests/applicationInsights.tests.ts

@@ -77,7 +77,10 @@ describe("ApplicationInsights", () => {
             WebSnippet.INSTANCE= undefined;
         });
 
-        afterEach(() => AppInsights.defaultClient = undefined);
+        afterEach(() => {
+            AppInsights.defaultClient = undefined;
+            AppInsights.liveMetricsClient = undefined;
+        });
 
         it("should warn if start is called before setup", () => {
             var warnStub = sandbox.stub(console, "warn");

applicationinsights.ts

@@ -120,7 +120,7 @@ function _setDefaultConfig() {
             defaultClient.config.enableAutoDependencyCorrelation = true;
         }
         if (defaultClient.config.enableSendLiveMetrics == undefined) {
-            defaultClient.config.enableSendLiveMetrics = true;
+            defaultClient.config.enableSendLiveMetrics = false;
         }
         if (defaultClient.config.enableAutoCollectExtendedMetrics == undefined) {
             defaultClient.config.enableAutoCollectExtendedMetrics = true;
@@ -154,8 +154,14 @@ export function start() {
         _serverRequests.enable(defaultClient.config.enableAutoCollectRequests);
         _clientRequests.enable(defaultClient.config.enableAutoCollectDependencies);
         _webSnippet.enable(defaultClient.config.enableWebInstrumentation, defaultClient.config.webInstrumentationConnectionString);
-        if (liveMetricsClient && defaultClient.config.enableSendLiveMetrics) {
-            liveMetricsClient.enable(defaultClient.config.enableSendLiveMetrics);
+        if (defaultClient.config.enableSendLiveMetrics) {
+            if (!liveMetricsClient) {
+                // No qps client exists. Create one and prepare it to be enabled at .start()
+                liveMetricsClient = new QuickPulseClient(defaultClient.config, defaultClient.context, defaultClient.getAuthorizationHandler);
+                _performanceLiveMetrics = new AutoCollectPerformance(liveMetricsClient as any, 1000, true);
+                liveMetricsClient.addCollector(_performanceLiveMetrics);
+                defaultClient.quickPulseClient = liveMetricsClient; // Need this so we can forward all manual tracks to live metrics via PerformanceMetricsTelemetryProcessor
+            }
         }
         _azureFunctions.enable(defaultClient.config.enableAutoCollectIncomingRequestAzureFunctions);
 
@@ -505,7 +511,6 @@ export function dispose() {
     }
     if (liveMetricsClient) {
         liveMetricsClient.enable(false);
-        defaultClient.config.enableSendLiveMetrics = false;
         liveMetricsClient = undefined;
     }
     if (_azureFunctions) {