Application Insights for Blazor web applications

Install

• Add BlazorApplicationInsights Nuget
  • dotnet add package BlazorApplicationInsights
• Add call to Program.cs
  • builder.Services.AddBlazorApplicationInsights();
• Add using statement to _Imports.razor
  • @using BlazorApplicationInsights;
• Add component to App.razor
  • <ApplicationInsightsComponent />
• Add Application Insights JS to head in index.html
  • Source
  • Set 'ld: -1' so that the page will be blocked until the JS is loaded and enter your instrumentationKey

    // This script is a simplified example, please click on Source above to get the full working script
    <script type="text/javascript">
    !function(T,l,y){ // Removed for brevity...
    src: "https://js.monitor.azure.com/scripts/b/ai.2.min.js", 
    ld: -1,  // Set this to -1
    crossOrigin: "anonymous",
    cfg: {
        instrumentationKey: "YOUR_INSTRUMENTATION_KEY_GOES_HERE"
    }});
    </script>

• Add JS Interop to the bottom of body in index.html

  <script src="_content/BlazorApplicationInsights/JsInterop.js"></script>

Example Project

Features

• Automatically triggers Track Page View on route changes
• ILoggerProvider which sends all the logs to App Insights (Wasm only)
• Supported APIs
  • AddTelemetryInitializer
  • ClearAuthenticatedUserContext
  • Flush
  • SetAuthenticatedUserContext
  • StartTrackEvent
  • StartTrackPage
  • StopTrackEvent
  • StopTrackPage
  • TrackDependencyData
  • TrackEvent
  • TrackException
  • TrackMetric
  • TrackPageView
  • TrackPageViewPerformance
  • TrackTrace

TrackEvent

@page "/"

<button class="btn btn-primary" @onclick="TrackEvent">Track Event</button>

@code {
    [Inject] private IApplicationInsights AppInsights { get; set; }

    private async Task TrackEvent()
    {
        await AppInsights.TrackEvent("My Event");
    }
}

Set User Name

• Edit Authentication.razor

@page "/authentication/{action}"

<RemoteAuthenticatorView Action="@Action" OnLogInSucceeded="OnLogInSucceeded" OnLogOutSucceeded="OnLogOutSucceeded" />

@code{
    [Parameter] public string Action { get; set; }

    [CascadingParameter] public Task<AuthenticationState> AuthenticationState { get; set; }

    [Inject] private IApplicationInsights AppInsights { get; set; }

    public async Task OnLogInSucceeded()
    {
        var user = (await AuthenticationState).User;

        await AppInsights.SetAuthenticatedUserContext(user.FindFirst("preferred_username")?.Value);
    }

    public async Task OnLogOutSucceeded()
    {
        await AppInsights.ClearAuthenticatedUserContext();
    }
}

Set Role and Instance

• Edit Program.cs

public static async Task Main(string[] args)
{
    var builder = WebAssemblyHostBuilder.CreateDefault(args);
    builder.RootComponents.Add<App>("app");

    builder.Services.AddTransient(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

    builder.Services.AddBlazorApplicationInsights(async applicationInsights =>
    {
        var telemetryItem = new TelemetryItem()
        {
            Tags = new Dictionary<string, object>()
            {
                { "ai.cloud.role", "SPA" },
                { "ai.cloud.roleInstance", "Blazor Wasm" },
            }
        };

        await applicationInsights.AddTelemetryInitializer(telemetryItem);
    });

    await builder.Build().RunAsync();
}

Set Instrumentation Key

• Edit Index.html and remove instrumentationKey from cfg

<script type="text/javascript">
!function(T,l,y){ // Removed for brevity...
src: "https://js.monitor.azure.com/scripts/b/ai.2.min.js", 
ld: -1,  // Set this to -1
crossOrigin: "anonymous",
cfg: {}
});
</script>

• Edit Program.cs

public static async Task Main(string[] args)
{
    var builder = WebAssemblyHostBuilder.CreateDefault(args);
    builder.RootComponents.Add<App>("app");

    builder.Services.AddTransient(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

    builder.Services.AddBlazorApplicationInsights(async applicationInsights =>
    {
        await applicationInsights.SetInstrumentationKey("YOUR_INSTRUMENTATION_KEY_GOES_HERE");
        await applicationInsights.LoadAppInsights();
    });

    await builder.Build().RunAsync();
}