public override AsyncUnaryCall <TResponse> AsyncUnaryCall <TRequest, TResponse>(TRequest request,
ClientInterceptorContext <TRequest, TResponse> context,
AsyncUnaryCallContinuation <TRequest, TResponse> continuation)
{
var currentRetry = 0;
string headerTimeout = context.GetHeaderStringValue(GrpcConstants.TimeoutMetadataKey, true);
int timeout = headerTimeout == null ? GrpcConstants.DefaultRequestTimeout : int.Parse(headerTimeout);
var timeoutSpan = TimeSpan.FromMilliseconds(timeout);
string headerRetryCount = context.GetHeaderStringValue(GrpcConstants.RetryCountMetadataKey, true);
int retryCount = headerRetryCount == null
? NetworkConstants.DefaultRequestRetryCount
: int.Parse(headerRetryCount);
async Task <TResponse> RetryCallback(Task <TResponse> responseTask)
{
var response = responseTask;
// if no problem occured return
if (!response.IsFaulted)
{
return(response.Result);
}
// if a problem occured but reached the max retries
if (currentRetry == retryCount)
{
return(response.Result);
}
currentRetry++;
// try again
var retryContext = BuildNewContext(context, timeoutSpan);
var result = GetResponseAsync(continuation(request, retryContext), timeoutSpan)
.ContinueWith(RetryCallback).Unwrap();
return(await result);
}
var newContext = BuildNewContext(context, timeoutSpan);
var responseContinuation = continuation(request, newContext);
var responseAsync = GetResponseAsync(responseContinuation, timeoutSpan).ContinueWith(RetryCallback)
.Unwrap();
return(new AsyncUnaryCall <TResponse>(
responseAsync,
responseContinuation.ResponseHeadersAsync,
responseContinuation.GetStatus,
responseContinuation.GetTrailers,
responseContinuation.Dispose));
}
public void GetHeader_Test()
{
var context = new ClientInterceptorContext <string, string>(null, null, new CallOptions());
context.GetHeaderStringValue(GrpcConstants.RetryCountMetadataKey).ShouldBeNull();
context = new ClientInterceptorContext <string, string>(null, null, new CallOptions(new Metadata()));
context.GetHeaderStringValue(GrpcConstants.RetryCountMetadataKey).ShouldBeNull();
Metadata data = new Metadata
{
{ GrpcConstants.TimeoutMetadataKey, "TimeoutMetadata" },
{ GrpcConstants.RetryCountMetadataKey, "2" }
};
context = new ClientInterceptorContext <string, string>(null, null, new CallOptions(data));
context.GetHeaderStringValue(GrpcConstants.TimeoutMetadataKey).ShouldBe("TimeoutMetadata");
context.GetHeaderStringValue(GrpcConstants.RetryCountMetadataKey).ShouldBe("2");
context.GetHeaderStringValue(GrpcConstants.TimeoutMetadataKey, true).ShouldBe("TimeoutMetadata");
context.GetHeaderStringValue(GrpcConstants.RetryCountMetadataKey, true).ShouldBe("2");
context.GetHeaderStringValue(GrpcConstants.TimeoutMetadataKey).ShouldBeNull();
context.GetHeaderStringValue(GrpcConstants.RetryCountMetadataKey).ShouldBeNull();
}
