503 Response being returned from Shinyproxy after page reload

[AlexisLenoirSoma]

Hi,

I can't reload my application page, it crashes systematically when I reload the page. My application pod is automatically deleted.
My environment:

• R Shiny application deployed on a kubernetes AKS cluster with ShinyProxy Operator behind Nginx ingress controller.

On the browser side:

• I get the message “This app has crashed and has been stopped.”
• The request my-host/app_proxy/d55fe0ad-acf7-42c3-9122-e33e700b2071/ returns a server error 503.

On the Nginx side:

 10.240.0.33 - - [13/Feb/2025:16:36:11 +0000] "GET /app_proxy/850e3590-7e07-48d5-89a1-27d02321547f/ HTTP/2.0" 503 38
2025/02/13 16:36:11 [warn] 8219#8219: *289309708 upstream sent more data than specified in "Content-Length" header while reading response header from upstream

On the ShinyProxy side:

2025-02-13T16:36:11.081Z ERROR 1 --- [   XNIO-1 I/O-2] io.undertow.proxy                        : UT005028: Proxy request to /proxy_endpoint/3846ac98-8ee31-4250-8d5e-99f4d21e6c24/ failed
                                                                                                                                                          
java.io.IOException: UT001000: Connection closed                                                                                                        
  at io.undertow.client.http.HttpClientConnection$ClientReadListener.handleEvent(HttpClientConnection.java:600) ~[undertowcore-2.3.13.Final.jar!/:2.3 
  at io.undertow.client.http.HttpClientConnection$ClientReadListener.handleEvent(HttpClientConnection.java:535) ~[undertowcore-2.3.13.Final.jar!/:2.3 
  at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]                             
  at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]       
  at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89) ~[xnio-nio-3.8.8.Final.jar!/:3.8.8.Final]                                    
  at org.xnio.nio.WorkerThread.run(WorkerThread.java:591) ~[xnio-nio-3.8.8.Final.jar!/:3.8.8.Final]


2025-02-13T16:36:11.081Z ERROR 1 --- [   XNIO-1 I/O-2] io.undertow.proxy                        : UT005028: Proxy request to /proxy_endpoint/3846ac98-8ee31-4250-8d5e-99f4d21e6c24/ failed

java.nio.channels.ClosedChannelException: null                                                                                                          
  at io.undertow.client.http.HttpClientConnection$5.handleEvent(HttpClientConnection.java:194) ~[undertow-core-2.3.13.Final.jar!/:2.3.13.Final]
  at io.undertow.client.http.HttpClientConnection$5.handleEvent(HttpClientConnection.java:177) ~[undertow-core-2.3.13.Final.jar!/:2.3.13.Final]
  at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]                     
  at org.xnio.StreamConnection.invokeCloseListener(StreamConnection.java:132) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]                                
  at org.xnio.Connection.close(Connection.java:142) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]                                                          
  at org.xnio.IoUtils.safeClose(IoUtils.java:152) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]                                                            
  at io.undertow.util.ConnectionUtils.doDrain(ConnectionUtils.java:90) ~[undertow-core-2.3.13.Final.jar!/:2.3.13.Final]                                
  at io.undertow.util.ConnectionUtils.cleanClose(ConnectionUtils.java:74) ~[undertow-core-2.3.13.Final.jar!/:2.3.13.Final]                             
  at io.undertow.client.http.HttpClientConnection.close(HttpClientConnection.java:491) ~[undertow-core-2.3.13.Final.jar!/:2.3.13.Final]
  at org.xnio.IoUtils.safeClose(IoUtils.java:152) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]
  at io.undertow.client.http.HttpClientConnection$ClientReadListener.handleEvent(HttpClientConnection.java:605) ~[undertow-core-2.3.13.Final.jar!/:2.3
  at io.undertow.client.http.HttpClientConnection$ClientReadListener.handleEvent(HttpClientConnection.java:535) ~[undertow-core-2.3.13.Final.jar!/:2.3 
  at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]
  at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66) ~[xnio-api-3.8.8.Final.jar!/:3.8.8.Final]
  at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89) ~[xnio-nio-3.8.8.Final.jar!/:3.8.8.Final]
  at org.xnio.nio.WorkerThread.run(WorkerThread.java:591) ~[xnio-nio-3.8.8.Final.jar!/:3.8.8.Final]  

2025-02-13T16:36:11.084Z  INFO 1 --- [   XNIO-1 I/O-2] e.o.c.util.ProxyMappingManager  Proxy unreachable/crashed, stopping it now, failed request: GET https://airpc-dev-test.dactika.com/proxy_endpoint/3846ac98-8e31-4250-8d

An error that's in the FAQ?
I checked to see if the error was related to Shiny's validation of the header size, as indicated in the FAQ “The assets of my Shiny app sometimes fail to load (HTTP error 503)” https://www.shinyproxy.io/faq/ . I've added these instructions to my Dockerfile and I still have the same problem. What's more, my problem doesn't happen sometimes, but always and only when the page reloads.

I thank you in advance !