Preview pane telemetry (microsoft#1299)

* Added telemetry base class and markdown telemetry class

* Updated docstring for telemetry event.

* Added telemetry to markdown for error

* Added try catch for markdown preview handler and display error bar

* Updated markdown telemetry to make event names global variable

* Updated parameter name to camel casing and telemetry event name naming.

* Corrected assembbly version for svg renderer

src/modules/previewpane/MarkDownPreviewHandler/MarkDownPreviewHandler.csproj

@@ -60,6 +60,7 @@
     <Compile Include="MarkdownPreviewHandlerControl.cs">
       <SubType>Form</SubType>
     </Compile>
+    <Compile Include="MarkdownTelemetry.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Properties\Resources.Designer.cs">
       <AutoGen>True</AutoGen>

src/modules/previewpane/MarkdownPreviewHandler/MarkdownPreviewHandlerControl.cs

@@ -12,7 +12,6 @@
 using System.Xml.Linq;
 using Common;
 using Markdig;
-using Markdig.Helpers;
 using MarkdownPreviewHandler.Properties;
 
 namespace MarkdownPreviewHandler
@@ -55,7 +54,7 @@ public class MarkdownPreviewHandlerControl : FormHandlerControl
         /// <summary>
         /// True if external image is blocked, false otherwise.
         /// </summary>
-        private bool imagesBlocked = false;
+        private bool infoBarDisplayed = false;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="MarkdownPreviewHandlerControl"/> class.
@@ -75,47 +74,51 @@ public override void DoPreview<T>(T dataSource)
         {
             this.InvokeOnControlThread(() =>
             {
-                this.imagesBlocked = false;
+                try
+                {
+                    this.infoBarDisplayed = false;
 
-                StringBuilder sb = new StringBuilder();
-                string filePath = dataSource as string;
-                string fileText = File.ReadAllText(filePath);
-                this.extension.BaseUrl = Path.GetDirectoryName(filePath);
+                    StringBuilder sb = new StringBuilder();
+                    string filePath = dataSource as string;
+                    string fileText = File.ReadAllText(filePath);
+                    this.extension.BaseUrl = Path.GetDirectoryName(filePath);
 
-                MarkdownPipeline pipeline = this.pipelineBuilder.Build();
-                string parsedMarkdown = Markdown.ToHtml(fileText, pipeline);
-                sb.AppendFormat("{0}{1}{2}", this.htmlHeader, parsedMarkdown, this.htmlFooter);
-                string markdownHTML = this.RemoveScriptFromHTML(sb.ToString());
+                    MarkdownPipeline pipeline = this.pipelineBuilder.Build();
+                    string parsedMarkdown = Markdown.ToHtml(fileText, pipeline);
+                    sb.AppendFormat("{0}{1}{2}", this.htmlHeader, parsedMarkdown, this.htmlFooter);
+                    string markdownHTML = this.RemoveScriptFromHTML(sb.ToString());
 
-                this.browser = new WebBrowser
-                {
-                    DocumentText = markdownHTML,
-                    Dock = DockStyle.Fill,
-                    IsWebBrowserContextMenuEnabled = false,
-                    ScriptErrorsSuppressed = true,
-                    ScrollBarsEnabled = true,
-                };
-                this.browser.Navigating += this.WebBrowserNavigating;
-                this.Controls.Add(this.browser);
-
-                if (this.imagesBlocked)
-                {
-                    this.infoBar = new RichTextBox
+                    this.browser = new WebBrowser
                     {
-                        Text = Resources.BlockedImageInfoText,
-                        BackColor = Color.LightYellow,
-                        Multiline = true,
-                        Dock = DockStyle.Top,
-                        ReadOnly = true,
+                        DocumentText = markdownHTML,
+                        Dock = DockStyle.Fill,
+                        IsWebBrowserContextMenuEnabled = false,
+                        ScriptErrorsSuppressed = true,
+                        ScrollBarsEnabled = true,
                     };
-                    this.infoBar.ContentsResized += this.RTBContentsResized;
-                    this.infoBar.ScrollBars = RichTextBoxScrollBars.None;
-                    this.infoBar.BorderStyle = BorderStyle.None;
+                    this.browser.Navigating += this.WebBrowserNavigating;
+                    this.Controls.Add(this.browser);
+
+                    if (this.infoBarDisplayed)
+                    {
+                        this.infoBar = this.GetTextBoxControl(Resources.BlockedImageInfoText);
+                        this.Controls.Add(this.infoBar);
+                    }
+
+                    this.Resize += this.FormResized;
+                    base.DoPreview(dataSource);
+                    MarkdownTelemetry.Log.MarkdownFilePreviewed();
+                }
+                catch (Exception e)
+                {
+                    MarkdownTelemetry.Log.MarkdownFilePreviewError(e.Message);
+                    this.infoBarDisplayed = true;
+                    this.infoBar = this.GetTextBoxControl(Resources.MarkdownNotPreviewedError);
+                    this.Resize += this.FormResized;
+                    this.Controls.Clear();
                     this.Controls.Add(this.infoBar);
+                    base.DoPreview(dataSource);
                 }
-
-                this.Resize += this.FormResized;
-                base.DoPreview(dataSource);
             });
         }
 
@@ -139,6 +142,28 @@ public string RemoveScriptFromHTML(string html)
             return doc.ToString();
         }
 
+        /// <summary>
+        /// Gets a textbox control.
+        /// </summary>
+        /// <param name="message">Message to be displayed in textbox.</param>
+        /// <returns>An object of type <see cref="RichTextBox"/>.</returns>
+        private RichTextBox GetTextBoxControl(string message)
+        {
+            RichTextBox richTextBox = new RichTextBox
+            {
+                Text = message,
+                BackColor = Color.LightYellow,
+                Multiline = true,
+                Dock = DockStyle.Top,
+                ReadOnly = true,
+            };
+            richTextBox.ContentsResized += this.RTBContentsResized;
+            richTextBox.ScrollBars = RichTextBoxScrollBars.None;
+            richTextBox.BorderStyle = BorderStyle.None;
+
+            return richTextBox;
+        }
+
         /// <summary>
         /// Callback when RichTextBox is resized.
         /// </summary>
@@ -157,7 +182,7 @@ private void RTBContentsResized(object sender, ContentsResizedEventArgs e)
         /// <param name="e">Provides data for the event.</param>
         private void FormResized(object sender, EventArgs e)
         {
-            if (this.imagesBlocked)
+            if (this.infoBarDisplayed)
             {
                 this.infoBar.Width = this.Width;
             }
@@ -168,7 +193,7 @@ private void FormResized(object sender, EventArgs e)
         /// </summary>
         private void ImagesBlockedCallBack()
         {
-            this.imagesBlocked = true;
+            this.infoBarDisplayed = true;
         }
 
         /// <summary>

src/modules/previewpane/MarkdownPreviewHandler/MarkdownTelemetry.cs

@@ -0,0 +1,71 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics.Tracing;
+using PreviewHandlerCommon.Telemetry;
+
+namespace MarkdownPreviewHandler
+{
+    /// <summary>
+    /// Telemetry helper class for markdown renderer.
+    /// </summary>
+    public class MarkdownTelemetry : TelemetryBase
+    {
+        /// <summary>
+        /// Name for ETW event.
+        /// </summary>
+        private const string EventSourceName = "Microsoft.PowerToys";
+
+        /// <summary>
+        /// ETW event name when markdown is previewed.
+        /// </summary>
+        private const string MarkdownFilePreviewedEventName = "PowerPreview_MDRenderer_Previewed";
+
+        /// <summary>
+        /// ETW event name when error is thrown during markdown preview.
+        /// </summary>
+        private const string MarkdownFilePreviewErrorEventName = "PowerPreview_MDRenderer_Error";
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MarkdownTelemetry"/> class.
+        /// </summary>
+        public MarkdownTelemetry()
+            : base(EventSourceName)
+        {
+            return;
+        }
+
+        /// <summary>
+        /// Gets an instance of the <see cref="MarkdownTelemetry"/> class.
+        /// </summary>
+        public static MarkdownTelemetry Log { get; } = new MarkdownTelemetry();
+
+        /// <summary>
+        /// Publishes ETW event when markdown is previewed successfully.
+        /// </summary>
+        public void MarkdownFilePreviewed()
+        {
+            this.Write(MarkdownFilePreviewedEventName, new EventSourceOptions()
+            {
+                Keywords = ProjectKeywordMeasure,
+                Tags = ProjectTelemetryTagProductAndServicePerformance,
+            });
+        }
+
+        /// <summary>
+        /// Publishes ETW event when markdown could not be previewed.
+        /// </summary>
+        public void MarkdownFilePreviewError(string message)
+        {
+            this.Write(
+                MarkdownFilePreviewErrorEventName,
+                new EventSourceOptions()
+                {
+                    Keywords = ProjectKeywordMeasure,
+                    Tags = ProjectTelemetryTagProductAndServicePerformance,
+                },
+                new { Message = message, });
+        }
+    }
+}

src/modules/previewpane/MarkdownPreviewHandler/Properties/Resources.resx

@@ -121,4 +121,8 @@
     <value>Some pictures have been blocked to help prevent the sender from identifying this computer. Open this item to view pictures.</value>
     <comment>This text is displayed if image is blocked from being displayed.</comment>
   </data>
+  <data name="MarkdownNotPreviewedError" xml:space="preserve">
+    <value>The markdown could not be preview due to an internal error.</value>
+    <comment>This text is displayed if markdown fails to preview</comment>
+  </data>
 </root>

src/modules/previewpane/common/PreviewHandlerCommon.csproj

@@ -79,6 +79,7 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="handlers\StreamBasedPreviewHandler.cs" />
     <Compile Include="examplehandler\TestCustomHandler.cs" />
+    <Compile Include="Telemetry\TelemetryBase.cs" />
     <Compile Include="Utilities\StreamWrapper.cs" />
   </ItemGroup>
   <ItemGroup>

src/modules/previewpane/common/Telemetry/TelemetryBase.cs

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics.Eventing.Reader;
+using System.Diagnostics.Tracing;
+
+namespace PreviewHandlerCommon.Telemetry
+{
+    /// <summary>
+    /// Base class for telemetry events.
+    /// </summary>
+    public class TelemetryBase : EventSource
+    {
+        /// <summary>
+        /// The event tag for this event source.
+        /// </summary>
+        public const EventTags ProjectTelemetryTagProductAndServicePerformance = (EventTags)0x0u;
+
+        /// <summary>
+        /// The event keyword for this event source.
+        /// </summary>
+        public const EventKeywords ProjectKeywordMeasure = (EventKeywords)0x0;
+
+        /// <summary>
+        /// Group ID for Powertoys project.
+        /// </summary>
+        private static readonly string[] PowerToysTelemetryTraits = { "ETW_GROUP", "{42749043-438c-46a2-82be-c6cbeb192ff2}" };
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="TelemetryBase"/> class.
+        /// </summary>
+        /// <param name="eventSourceName">.</param>
+        public TelemetryBase(
+            string eventSourceName)
+            : base(
+            eventSourceName,
+            EventSourceSettings.EtwSelfDescribingEventFormat,
+            PowerToysTelemetryTraits)
+        {
+            return;
+        }
+    }
+}