/// <summary>
/// Wait for the given number of metric requests to appear.
/// </summary>
/// <param name="count">The expected number of metric requests.</param>
/// <param name="timeout">The timeout</param>
/// <returns>The list of metric requests.</returns>
public IImmutableList <ExportMetricsServiceRequest> WaitForMetrics(
int count,
TimeSpan?timeout = null)
{
timeout ??= DefaultWaitTimeout;
var deadline = DateTime.Now.Add(timeout.Value);
IImmutableList <ExportMetricsServiceRequest> relevantMetricRequests = ImmutableList <ExportMetricsServiceRequest> .Empty;
while (DateTime.Now < deadline)
{
relevantMetricRequests =
MetricsMessages
.Where(m => MetricFilters.All(shouldReturn => shouldReturn(m)))
.ToImmutableList();
if (relevantMetricRequests.Count >= count)
{
break;
}
Thread.Sleep(500);
}
return(relevantMetricRequests);
}
private void HandleHttpRequests()
{
while (_listener.IsListening)
{
try
{
var ctx = _listener.GetContext();
OnRequestReceived(ctx);
if (ctx.Request.RawUrl.Equals("/healthz", StringComparison.OrdinalIgnoreCase))
{
CreateHealthResponse(ctx);
continue;
}
if (ctx.Request.RawUrl.Equals("/v1/metrics", StringComparison.OrdinalIgnoreCase))
{
if (ShouldDeserializeMetrics)
{
var metricsMessage = ExportMetricsServiceRequest.Parser.ParseFrom(ctx.Request.InputStream);
OnRequestDeserialized(metricsMessage);
lock (this)
{
// we only need to lock when replacing the metric collection,
// not when reading it because it is immutable
MetricsMessages = MetricsMessages.Add(metricsMessage);
RequestHeaders = RequestHeaders.Add(new NameValueCollection(ctx.Request.Headers));
}
}
// NOTE: HttpStreamRequest doesn't support Transfer-Encoding: Chunked
// (Setting content-length avoids that)
ctx.Response.ContentType = "application/x-protobuf";
ctx.Response.StatusCode = (int)HttpStatusCode.OK;
var responseMessage = new ExportMetricsServiceResponse();
ctx.Response.ContentLength64 = responseMessage.CalculateSize();
responseMessage.WriteTo(ctx.Response.OutputStream);
ctx.Response.Close();
continue;
}
// We received an unsupported request
ctx.Response.StatusCode = (int)HttpStatusCode.NotImplemented;
ctx.Response.Close();
}
catch (HttpListenerException)
{
// listener was stopped,
// ignore to let the loop end and the method return
}
catch (ObjectDisposedException)
{
// the response has been already disposed.
}
catch (InvalidOperationException)
{
// this can occur when setting Response.ContentLength64, with the framework claiming that the response has already been submitted
// for now ignore, and we'll see if this introduces downstream issues
}
catch (Exception) when(!_listener.IsListening)
{
// we don't care about any exception when listener is stopped
}
}
}