public void Handle(IHttpRequest request, IHttpResponse response)
{
// Largely cribbed from https://github.com/prometheus-net/prometheus-net/blob/master/Prometheus.NetStandard/MetricServer.cs
MetricFamily[] metrics;
try
{
metrics = _registry.CollectAll().ToArray();
_logger.Trace($"{nameof(MetricsActivityHandler)}.{nameof(Handle)}",
new LogItem("Event", "CollectAll result"),
new LogItem("MetricsCount", metrics.Length));
var acceptHeader = request.RequestHeader["Accept"];
var acceptHeaders = acceptHeader?.Split(',');
var contentType = ScrapeHandler.GetContentType(acceptHeaders);
response.HttpStatusCode = HttpStatusCode.OK;
response.HttpContent = new MetricsHttpContent(_logger, metrics, contentType);
}
catch (Exception ex)
{
_logger.Error($"{nameof(MetricsActivityHandler)}.{nameof(Handle)}",
new LogItem("Event", "ScrapeFailed"),
new LogItem("Exception", ex.Message),
new LogItem("StackTrace", ex.StackTrace));
response.HttpStatusCode = HttpStatusCode.ServiceUnavailable;
response.SetStringContent(ex.Message);
}
}
public IActionResult Index()
{
try
{
var metrics = _registry.CollectAll().ToArray();
_logger.Trace($"{nameof(MetricsController)}.{nameof(Handle)}",
new LogItem("Event", "CollectAll result"),
new LogItem("MetricsCount", metrics.Length));
var acceptHeader = Request.Headers["Accept"];
var acceptHeaders = acceptHeader.ToArray();
var contentType = ScrapeHandler.GetContentType(acceptHeaders);
var metricsContent = new MetricsHttpContent(_logger, metrics, contentType);
Response.StatusCode = (int)HttpStatusCode.OK;
Response.ContentType = contentType;
metricsContent.WriteToStream(Response.Body);
return(new EmptyResult());
}
catch (Exception ex)
{
_logger.Error($"{nameof(MetricsController)}.{nameof(Handle)}",
new LogItem("Event", "ScrapeFailed"),
new LogItem("Exception", ex.Message),
new LogItem("StackTrace", ex.StackTrace));
return(StatusCode((int)HttpStatusCode.ServiceUnavailable, ex.Message));
}
}
private void StartLoop(IScheduler scheduler)
{
//delegate allocations below - but that's fine as it's not really on the "critical path" (polled relatively infrequently) - and it's much more readable this way
scheduler.Schedule(repeatAction => _httpListener.BeginGetContext(ar =>
{
try
{
var httpListenerContext = _httpListener.EndGetContext(ar);
var request = httpListenerContext.Request;
var response = httpListenerContext.Response;
response.StatusCode = 200;
var acceptHeader = request.Headers.Get("Accept");
var acceptHeaders = acceptHeader == null ? null : acceptHeader.Split(',');
var contentType = ScrapeHandler.GetContentType(acceptHeaders);
response.ContentType = contentType;
using (var outputStream = response.OutputStream)
{
var collected = _registry.CollectAll();
ScrapeHandler.ProcessScrapeRequest(collected, contentType, outputStream);
}
response.Close();
}
catch (Exception e)
{
Trace.WriteLine(string.Format("Error in MetricsServer: {0}", e));
}
repeatAction.Invoke();
}, null));
}
public void Configure(IApplicationBuilder app)
{
app.Run(context =>
{
if (context.Request.Path == _url)
{
var response = context.Response;
var request = context.Request;
response.StatusCode = 200;
var acceptHeader = request.Headers["Accept"];
var contentType = ScrapeHandler.GetContentType(acceptHeader);
response.ContentType = contentType;
using (var outputStream = response.Body)
{
var collected = _registry.CollectAll();
ScrapeHandler.ProcessScrapeRequest(collected, contentType, outputStream);
}
return(Task.FromResult(true));
}
context.Response.StatusCode = 404;
return(Task.FromResult(true));
});
}
protected static Stream CollectionToStreamWriter(ICollectorRegistry registry)
{
var metrics = registry.CollectAll();
var stream = new MemoryStream();
ScrapeHandler.ProcessScrapeRequest(metrics, ContentType, stream);
stream.Position = 0;
return(stream);
}
public static MemoryStream Process(ICollectorRegistry registry)
{
// leave open
var stream = new MemoryStream();
var collected = registry.CollectAll();
TextFormatter.Format(stream, collected.ToArray());
stream.Position = 0;
return(stream);
}
public async Task WriteAsync(StreamWriter writer)
{
if (writer is null)
{
throw new ArgumentNullException(nameof(writer));
}
var collected = _registry.CollectAll();
await Serializer.SerializeAsync(writer, collected).ConfigureAwait(false);
}
public async Task Invoke(HttpContext context)
{
// We just handle the root URL (/metrics or whatnot).
if (!string.IsNullOrWhiteSpace(context.Request.Path.Value))
{
await _next(context);
return;
}
var request = context.Request;
var response = context.Response;
var acceptHeaders = request.Headers["Accept"];
var contentType = ScrapeHandler.GetContentType(acceptHeaders);
response.ContentType = contentType;
IEnumerable <MetricFamily> metrics;
try
{
metrics = _registry.CollectAll();
}
catch (ScrapeFailedException ex)
{
response.StatusCode = 503;
if (!string.IsNullOrWhiteSpace(ex.Message))
{
using (var writer = new StreamWriter(response.Body))
await writer.WriteAsync(ex.Message);
}
return;
}
response.StatusCode = 200;
using (var outputStream = response.Body)
ScrapeHandler.ProcessScrapeRequest(metrics, contentType, outputStream);
}
public static void Process(ICollectorRegistry registry, Stream outputStream)
{
var collected = registry.CollectAll();
TextFormatter.Format(outputStream, collected.ToArray());
}
public override void Act()
{
_pushService.PushAsync(_metrics.CollectAll(), "http://localhost:9091",
"pushgateway", Environment.MachineName, null).GetAwaiter().GetResult();
}
private Task StartServer(CancellationToken cancel)
{
_httpListener.Start();
return(Task.Factory.StartNew(delegate
{
try
{
while (!cancel.IsCancellationRequested)
{
var getContext = _httpListener.GetContextAsync();
getContext.Wait(cancel);
var context = getContext.Result;
var request = context.Request;
var response = context.Response;
try
{
if (authMode == "None" || CheckAuthenticate(context))
{
IEnumerable <MetricFamily> metrics;
metrics = _registry.CollectAll();
var acceptHeader = request.Headers.Get("Accept");
var acceptHeaders = acceptHeader?.Split(',');
var contentType = ScrapeHandler.GetContentType(acceptHeaders);
response.ContentType = contentType;
response.StatusCode = 200;
using (var outputStream = response.OutputStream)
ScrapeHandler.ProcessScrapeRequest(metrics, contentType, outputStream);
}
else
{
throw new InvalidHeader();
}
}
catch (InvalidHeader ex)
{
response.StatusCode = 404;
//tell something about invalid header
}
catch (Exception ex) when(!(ex is OperationCanceledException))
{
Trace.WriteLine(string.Format("Error in MetricsServer: {0}", ex));
response.StatusCode = 404;
}
finally
{
response.Close();
}
}
}
finally
{
_httpListener.Stop();
_httpListener.Close();
}
}, TaskCreationOptions.LongRunning));
}
