/// <summary>
/// Adds the needed services for Google Cloud Tracing. Used with <see cref="UseGoogleTrace"/>.
/// </summary>
/// <param name="services">The service collection. Cannot be null.</param>
/// <param name="setupAction">Action to set up options. Cannot be null.</param>
/// <remarks>
/// If <see cref="RetryOptions.ExceptionHandling"/> is set to <see cref="ExceptionHandling.Propagate"/>
/// and the <see cref="RequestDelegate"/> executed by this middleware throws ad exception and this
/// diagnostics library also throws an exception trying to report it and <see cref="AggregateException"/>
/// with both exceptions will be thrown. Otherwise only the exception from the <see cref="RequestDelegate"/>
/// will be thrown.
/// </remarks>
public static IServiceCollection AddGoogleTrace(
this IServiceCollection services, Action <TraceServiceOptions> setupAction)
{
GaxPreconditions.CheckNotNull(services, nameof(services));
GaxPreconditions.CheckNotNull(setupAction, nameof(setupAction));
var serviceOptions = new TraceServiceOptions();
setupAction(serviceOptions);
var client = serviceOptions.Client ?? TraceServiceClient.Create();
var options = serviceOptions.Options ?? TraceOptions.Create();
var traceFallbackPredicate = serviceOptions.TraceFallbackPredicate ?? TraceDecisionPredicate.Default;
var projectId = Project.GetAndCheckProjectId(serviceOptions.ProjectId);
var consumer = ManagedTracer.CreateConsumer(client, options);
var tracerFactory = ManagedTracer.CreateTracerFactory(projectId, consumer, options);
services.AddScoped(CreateTraceHeaderContext);
services.AddSingleton(tracerFactory);
// Only add the HttpContextAccessor if it's not already added.
// This is needed to get the `TraceHeaderContext`. See `CreateTraceHeaderContext`.
services.TryAddSingleton <IHttpContextAccessor, HttpContextAccessor>();
services.AddSingleton(ManagedTracer.CreateDelegatingTracer(() => ContextTracerManager.GetCurrentTracer()));
services.AddSingleton(new TraceHeaderPropagatingHandler(() => ContextTracerManager.GetCurrentTracer()));
return(services.AddSingleton(traceFallbackPredicate));
}
private void SetTraceAndSpanIfAny(LogEntry entry)
{
if (_traceTarget is null)
{
return;
}
string traceId = null;
ulong? spanId = null;
// If there's currently a Google trace and span use that one.
// This means that the Google Trace component of the diagnostics library
// has been initialized.
if (ContextTracerManager.GetCurrentTracer() is IManagedTracer tracer && tracer.GetCurrentTraceId() is string googleTraceId)
{
traceId = googleTraceId;
spanId = tracer.GetCurrentSpanId();
}
/// <summary>
/// Creates a singleton <see cref="IManagedTracer"/> that is a <see cref="DelegatingTracer"/>.
/// The <see cref="DelegatingTracer"/> will use an <see cref="IHttpContextAccessor"/> under the hood
/// to get the current tracer which is set by the <see cref="ContextTracerManager"/>.
/// </summary>
internal static IManagedTracer CreateManagedTracer(IServiceProvider provider)
{
var accessor = provider.GetServiceCheckNotNull <IHttpContextAccessor>();
return(new DelegatingTracer(() => ContextTracerManager.GetCurrentTracer(accessor)));
}
