/// <summary>
/// Invokes the next <see cref="RequestDelegate"/> and traces the time
/// taken for the next delegate to run, reporting the results to the
/// Google Cloud Trace API.
/// </summary>
/// <param name="httpContext">The current HTTP context.</param>
/// <param name="traceContext">Trace information from the current request. Must not be null.</param>
/// <param name="fallback">Predicate to be used if the trace context has no information about whether
/// the request should be traced or not.</param>
/// <param name="traceContextPropagator">Trace context propagator to be used to set the trace context
/// on the <see cref="HttpResponse"/>. Must not be null.</param>
public async Task Invoke(
HttpContext httpContext, ITraceContext traceContext, TraceDecisionPredicate fallback, Action <HttpResponse, ITraceContext> traceContextPropagator)
{
GaxPreconditions.CheckNotNull(traceContext, nameof(traceContext));
GaxPreconditions.CheckNotNull(traceContextPropagator, nameof(traceContextPropagator));
// Applies the trace decision fallback, if needed.
traceContext = WithShouldTraceFallback(traceContext, fallback.ShouldTrace(httpContext.Request));
// Create a tracer for the given request and set it on the context manager so
// the tracer can be used in other places.
var tracer = _tracerFactory(traceContext);
ContextTracerManager.SetCurrentTracer(tracer);
if (tracer.GetCurrentTraceId() == null)
{
await _next(httpContext).ConfigureAwait(false);
}
else
{
if (traceContext.TraceId != null)
{
// Set the current trace context on the response.
var currentTraceContext = ContextTracerManager.GetCurrentTraceContext();
traceContextPropagator.Invoke(httpContext.Response, currentTraceContext);
}
// Trace the delegate and annotate it with information from the current
// HTTP context.
var traceName = await _nameProvider.GetTraceNameAsync(httpContext).ConfigureAwait(false);
var span = tracer.StartSpan(traceName);
try
{
await _next(httpContext).ConfigureAwait(false);
}
catch (Exception exception)
{
try
{
StackTrace stackTrace = new StackTrace(exception, true);
tracer.SetStackTrace(stackTrace);
}
catch (Exception innerException)
{
throw new AggregateException(innerException, exception);
}
throw;
}
finally
{
tracer.AnnotateSpan(Labels.AgentLabel);
tracer.AnnotateSpan(Labels.FromHttpContext(httpContext));
span.Dispose();
}
}
}
/// <summary>
/// Invokes the next <see cref="RequestDelegate"/> and traces the time
/// taken for the next delegate to run, reporting the results to the
/// Stackdriver Trace API.
/// </summary>
/// <param name="httpContext">The current HTTP context.</param>
/// <param name="traceHeaderContext">Information from the current request header. Must not be null.</param>
public async Task Invoke(HttpContext httpContext, TraceHeaderContext traceHeaderContext)
{
GaxPreconditions.CheckNotNull(traceHeaderContext, nameof(traceHeaderContext));
// Create a tracer for the given request and set it on the context manager so
// the tracer can be used in other places.
var tracer = _tracerFactory(traceHeaderContext);
ContextTracerManager.SetCurrentTracer(tracer);
if (tracer.GetCurrentTraceId() == null)
{
await _next(httpContext).ConfigureAwait(false);
}
else
{
if (traceHeaderContext.TraceId != null)
{
// Set the trace updated trace header on the response.
var updatedHeaderContext = TraceHeaderContext.Create(
tracer.GetCurrentTraceId(), tracer.GetCurrentSpanId() ?? 0, true);
httpContext.Response.Headers.Add(
TraceHeaderContext.TraceHeader, updatedHeaderContext.ToString());
}
// Trace the delegate and annotate it with information from the current
// HTTP context.
var traceName = await _nameProvider.GetTraceNameAsync(httpContext).ConfigureAwait(false);
var span = tracer.StartSpan(traceName);
try
{
await _next(httpContext).ConfigureAwait(false);
}
catch (Exception exception)
{
try
{
StackTrace stackTrace = new StackTrace(exception, true);
tracer.SetStackTrace(stackTrace);
}
catch (Exception innerException)
{
throw new AggregateException(innerException, exception);
}
throw;
}
finally
{
tracer.AnnotateSpan(Labels.AgentLabel);
tracer.AnnotateSpan(Labels.FromHttpContext(httpContext));
span.Dispose();
}
}
}
