Add initial telemetry for schema compare (#5595)

* add initial telemetry to schema compare

* addressing comments

extensions/schema-compare/src/telemetry.ts

@@ -0,0 +1,102 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+import * as vscode from 'vscode';
+import TelemetryReporter from 'vscode-extension-telemetry';
+
+import * as Utils from './utils';
+
+const packageJson = require('../package.json');
+
+export interface ITelemetryEventProperties {
+	[key: string]: string;
+}
+
+export interface ITelemetryEventMeasures {
+	[key: string]: number;
+}
+
+/**
+ * Filters error paths to only include source files. Exported to support testing
+ */
+export function filterErrorPath(line: string): string {
+	if (line) {
+		let values: string[] = line.split('/out/');
+		if (values.length <= 1) {
+			// Didn't match expected format
+			return line;
+		} else {
+			return values[1];
+		}
+	}
+}
+
+export class Telemetry {
+	private static reporter: TelemetryReporter;
+	private static disabled: boolean;
+
+	/**
+	 * Disable telemetry reporting
+	 */
+	public static disable(): void {
+		this.disabled = true;
+	}
+
+	/**
+	 * Initialize the telemetry reporter for use.
+	 */
+	public static initialize(): void {
+		if (typeof this.reporter === 'undefined') {
+			// Check if the user has opted out of telemetry
+			if (!vscode.workspace.getConfiguration('telemetry').get<boolean>('enableTelemetry', true)) {
+				this.disable();
+				return;
+			}
+
+			let packageInfo = Utils.getPackageInfo(packageJson);
+			this.reporter = new TelemetryReporter(packageInfo.name, packageInfo.version, packageInfo.aiKey);
+		}
+	}
+
+	/**
+		 * Send a telemetry event for a general error
+		 * @param err The error to log
+		 */
+	public static sendTelemetryEventForError(err: string, properties?: ITelemetryEventProperties): void {
+		this.sendTelemetryEvent('Error', { error: err, ...properties });
+	}
+
+	/**
+	 * Send a telemetry event using application insights
+	 */
+	public static sendTelemetryEvent(
+		eventName: string,
+		properties?: ITelemetryEventProperties,
+		measures?: ITelemetryEventMeasures): void {
+
+		if (typeof this.disabled === 'undefined') {
+			this.disabled = false;
+		}
+
+		if (this.disabled || typeof (this.reporter) === 'undefined') {
+			// Don't do anything if telemetry is disabled
+			return;
+		}
+
+		if (!properties || typeof properties === 'undefined') {
+			properties = {};
+		}
+
+		try {
+			this.reporter.sendTelemetryEvent(eventName, properties, measures);
+		} catch (telemetryErr) {
+			// If sending telemetry event fails ignore it so it won't break the extension
+			console.error('Failed to send telemetry event. error: ' + telemetryErr);
+		}
+	}
+}
+
+Telemetry.initialize();