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Azure SDK diagnostics

NOTE: Samples in this file apply only to packages that follow Azure SDK Design Guidelines. Names of such packages usually start with Azure. The samples make use of the SecretClientOptions type, but the same functionality is available for any of the Azure. packages that contain client options types that derive from ClientOptions, e.g. BlobClientOptions, TextAnalyticsClientOptions, etc.

Logging

Azure SDKs produce various log messages that include information about:

  1. Requests and responses
  2. Authentication attempts
  3. Retries

The simplest way to see the logs is to enable the console logging.

// Setup a listener to monitor logged events.
using AzureEventSourceListener listener = AzureEventSourceListener.CreateConsoleLogger();

Enabling content logging

By default only URI and headers are logged. To enable content logging, set the Diagnostics.IsLoggingContentEnabled client option:

SecretClientOptions options = new SecretClientOptions()
{
    Diagnostics =
    {
        IsLoggingContentEnabled = true
    }
};

NOTE: The content is logged at the Verbose level so you might need to change the listener settings for content logs to appear.

Changing log level

The CreateConsoleLogger method has an optional parameter that specifies a minimum log level to display messages for.

using AzureEventSourceListener listener = AzureEventSourceListener.CreateConsoleLogger(EventLevel.Warning);

Logging redacted headers and query parameters

Some sensitive headers and query parameters are not logged by default and are displayed as "REDACTED", to include them in logs use the Diagnostics.LoggedHeaderNames and Diagnostics.LoggedQueryParameters client options.

SecretClientOptions options = new SecretClientOptions()
{
    Diagnostics =
    {
        LoggedHeaderNames = { "x-ms-request-id" },
        LoggedQueryParameters = { "api-version" }
    }
};

You can also disable redaction completely by adding a "*" to collections mentioned above.

SecretClientOptions options = new SecretClientOptions()
{
    Diagnostics =
    {
        LoggedHeaderNames = { "*" },
        LoggedQueryParameters = { "*" }
    }
};

ASP.NET Core applications

If your are using Azure SDK libraries in ASP.NET Core application consider using the Microsoft.Extensions.Azure package that provides integration with Microsoft.Extensions.Logging library. See Microsoft.Extensions.Azure readme for more details.

Custom logging callback

The AzureEventSourceListener class can also be used with a custom callback that allows log messages to be written to destination of your choice.

using AzureEventSourceListener listener = new AzureEventSourceListener(
    (e, message) => Console.WriteLine("[{0:HH:mm:ss:fff}][{1}] {2}", DateTimeOffset.Now, e.Level, message),
    level: EventLevel.Verbose);

When targeting .NET Standard 2.1, .NET Core 2.2, or newer, you might instead use e.TimeStamp to log the time the event was written instead of rendered, like above. It's in UTC format, so if you want to log the local time like in the example call ToLocaleTime() first. For help diagnosing multi-threading issues, you might also log e.OSThreadId which is also available on those same targets.

ActivitySource support

Azure SDKs released after October 2021 include experimental support for ActivitySource, which is a simplified way to create and listen to activities added in .NET 5. Azure SDKs produce the following kinds of Activities:

  • HTTP calls: every HTTP call originating from Azure SDKs
  • client method calls: for example, BlobClient.DownloadTo or SecretClient.StartDeleteSecret.
  • messaging events: Event Hubs and Service Bus message creation is traced and correlated with its sending, receiving, and processing.

Because ActivitySource support is experimental, the shape of Activities may change in the future without notice. This includes:

  • the kinds of operations that are tracked
  • relationships between telemetry spans
  • attributes attached to telemetry spans

More detailed distributed tracing convention can be found at https://github.com/Azure/azure-sdk/blob/main/docs/tracing/distributed-tracing-conventions.yml .

ActivitySource support can be enabled through either of these three steps:

  • Set the AZURE_EXPERIMENTAL_ENABLE_ACTIVITY_SOURCE environment variable to true.
  • Set the Azure.Experimental.EnableActivitySource context switch to true in your application code:
AppContext.SetSwitch("Azure.Experimental.EnableActivitySource", true);
  • Add the RuntimeHostConfigurationOption setting to your .csproj.
 <ItemGroup>
    <RuntimeHostConfigurationOption Include="Azure.Experimental.EnableActivitySource" Value="true" />
  </ItemGroup>

You'll need System.Diagnostics.DiagnosticSource package with version 5.0 or later consume Azure SDK Activities.

 <ItemGroup>
    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="5.0.1" />
  </ItemGroup>

The following sample shows how ActivityListener can be used to listen to Azure SDK Activities.

using ActivityListener listener = new ActivityListener()
{
    ShouldListenTo = a => a.Name.StartsWith("Azure"),
    Sample = (ref ActivityCreationOptions<ActivityContext> _) => ActivitySamplingResult.AllData,
    SampleUsingParentId = (ref ActivityCreationOptions<string> _) => ActivitySamplingResult.AllData,
    ActivityStarted = activity => Console.WriteLine("Start: " + activity.DisplayName),
    ActivityStopped = activity => Console.WriteLine("Stop: " + activity.DisplayName)
};
ActivitySource.AddActivityListener(listener);

var secretClient = new SecretClient(new Uri("https://example.com"), new DefaultAzureCredential());
secretClient.GetSecret("<secret-name>");

Distributed tracing

Azure SDKs are instrumented for distributed tracing using ApplicationsInsights or OpenTelemetry.

ApplicationInsights with Azure Monitor

Application Insights, a feature of Azure Monitor, is an extensible Application Performance Management (APM) service for developers and DevOps professionals. Use it to monitor your live applications. It will automatically detect performance anomalies, and includes powerful analytics tools to help you diagnose issues and to understand what users actually do with your app

If your application already uses ApplicationInsights, automatic collection of Azure SDK traces is supported since version 2.12.0 (Microsoft.ApplicationInsights on NuGet).

To setup ApplicationInsights tracking for your application follow the Start Monitoring Application guide.

OpenTelemetry with Azure Monitor, Zipkin and others

OpenTelemetry relies on ActivitySource to collect distributed traces. Follow steps in [ActivitySource support](#ActivitySource support) section before proceeding to OpenTelemetry configuration.

Follow the OpenTelemetry configuration guide to configure collecting distribute tracing event collection using the OpenTelemetry library.

Sample

To see an example of distributed tracing in action, take a look at our sample app that combines several Azure SDKs.

Setting x-ms-client-request-id value sent with requests

By default x-ms-client-request-id header gets a unique value per client method call. If you would like to use a specific value for a set of requests use the HttpPipeline.CreateClientRequestIdScope method.

var secretClient = new SecretClient(new Uri("http://example.com"), new DefaultAzureCredential());

using (HttpPipeline.CreateClientRequestIdScope("<custom-client-request-id>"))
{
    // The HTTP request resulting from the client call would have x-ms-client-request-id value set to <custom-client-request-id>
    secretClient.GetSecret("<secret-name>");
}