Hub proxy returns graceful responses when an instance is unavailable instead of a generic bad gateway error (#956)

1 files changed, 27 insertions, 3 deletions

diff --git a/src/zenserver/hub/httpproxyhandler.cpp b/src/zenserver/hub/httpproxyhandler.cpp
index 25842623a..235d7388f 100644
--- a/src/zenserver/hub/httpproxyhandler.cpp
+++ b/src/zenserver/hub/httpproxyhandler.cpp
@@ -202,7 +202,7 @@ HttpProxyHandler::HandleProxyRequest(HttpServerRequest& Request, std::string_vie
 
 	if (!m_ValidatePort(Port))
 	{
-		Request.WriteResponse(HttpResponseCode::BadGateway, HttpContentType::kText, "target instance not available");
+		Request.WriteResponse(HttpResponseCode::NotFound, HttpContentType::kText, "target instance not available");
 		return;
 	}
 
@@ -271,9 +271,33 @@ HttpProxyHandler::HandleProxyRequest(HttpServerRequest& Request, std::string_vie
 
 	if (Response.Error)
 	{
+		if (!m_ValidatePort(Port))
+		{
+			Request.WriteResponse(HttpResponseCode::NotFound, HttpContentType::kText, "target instance not available");
+			return;
+		}
+
 		ZEN_WARN("proxy request to port {} failed: {}", Port, Response.Error->ErrorMessage);
-		Request.WriteResponse(HttpResponseCode::BadGateway, HttpContentType::kText, "upstream request failed");
-		return;
+		switch (Response.Error->ErrorCode)
+		{
+			case HttpClientErrorCode::kConnectionFailure:
+			case HttpClientErrorCode::kHostResolutionFailure:
+				return Request.WriteResponse(HttpResponseCode::NotFound,
+											 HttpContentType::kText,
+											 fmt::format("instance not reachable: {}", Response.Error->ErrorMessage));
+			case HttpClientErrorCode::kOperationTimedOut:
+				return Request.WriteResponse(HttpResponseCode::GatewayTimeout,
+											 HttpContentType::kText,
+											 fmt::format("upstream request timed out: {}", Response.Error->ErrorMessage));
+			case HttpClientErrorCode::kRequestCancelled:
+				return Request.WriteResponse(HttpResponseCode::ServiceUnavailable,
+											 HttpContentType::kText,
+											 fmt::format("upstream request cancelled: {}", Response.Error->ErrorMessage));
+			default:
+				return Request.WriteResponse(HttpResponseCode::BadGateway,
+											 HttpContentType::kText,
+											 fmt::format("upstream request failed: {}", Response.Error->ErrorMessage));
+		}
 	}
 
 	HttpContentType ContentType = Response.ResponsePayload.GetContentType();