public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
{
Debug.Assert(!string.IsNullOrEmpty(this.RequestName));
AsyncOperation asyncOp = new AsyncOperation(cb, context, extraData, this, ServicePath, RequestName.ToLower());
if (!asyncOp.IsAsync)
{
// Continue tracing if traceId & spanId are provided in request header
var traceIdString = context.Request.Headers[ServiceUtils.TRACE_ID_HTTP_HEADER] ?? context.Request.Headers[ServiceUtils.ESB_TRACE_ID_HTTP_HEADER];
if (!string.IsNullOrWhiteSpace(traceIdString))
{
context.Response.AddHeader(ServiceUtils.TRACE_ID_HTTP_HEADER, traceIdString);
}
var parentSpanIdString = context.Request.Headers[ServiceUtils.SPAN_ID_HTTP_HEADER] ?? context.Request.Headers[ServiceUtils.ESB_SPAN_ID_HTTP_HEADER];
if (traceIdString != null && parentSpanIdString != null)
{
try
{
var traceId = long.Parse(traceIdString);
var parentSpanId = long.Parse(parentSpanIdString);
}
catch (Exception)
{
// no tracing
}
}
asyncOp.ContinueCatTransaction();
}
else
{
HostContext.Instance.Request.Items[ServiceCatConstants.SOA2AsyncServiceStartTimeKey] = DateTime.Now;
}
try
{
//检查单个IP的连接数是否超标
CheckConnectionMaxRequestCount(context);
//电容保护针对每个方法
var hystrixCommand = EndpointHost.Config.MetadataMap[ServicePath].GetHystrixCommandByOpName(this.RequestName);
var hystrixMetrics = hystrixCommand.Metrics;
var hystrixCircuitBreaker = hystrixCommand.CircuitBreaker;
// We fallback if circuit is open
if (!hystrixCircuitBreaker.AllowRequest())
{
hystrixMetrics.MarkShortCircuited();
//设置_slaErrorSent
asyncOp.SendSyncSLAErrorResponse(HystrixEventType.ShortCircuited);
if (asyncOp.IsAsync)
{
// var message = "Circuit Breaker is open. Server entered into self-protecting mode";
}
return(asyncOp);
}
if (asyncOp.IsAsync)
{
// The circuit is healthy, We can start async work
hystrixMetrics.IncrementConcurrentExecutionCount();
EndpointHost.Config.MetadataMap[ServicePath].IncrementConcurrentExecutionCount();
asyncOp.StartAsyncWork();
}
else // sync mode
{
asyncOp.StartSyncWork();
}
return(asyncOp);
}
catch (Exception)
{
throw;
}
finally
{
}
}
