Unexpected and Unpredictable Shiny App Terminations with Shinyproxy

Hello everyone,

I am reaching out for insights or solutions to an issue we are encountering with our ShinyProxy deployment. We are running ShinyProxy version 3.0.2 on an AWS EC2 instance with AWS Linux 2023, and we’ve been observing that occassionally our Shiny app stops unexpectedly and unpredictably after running normally for some (or better, the most of) time. Afterwards, the users are always able to reload the app successfully.

There are no errors in the container logs, and the container monitoring suggests that the containers are simply being stopped. However, we have noticed the following error messages in the ShinyProxy logs:

  1. A DockerRequestException indicating that Shinyproxy is attempting to access information about a Docker container that appears to be non-existent:
Caused by: com.spotify.docker.client.exceptions.DockerRequestException: Request error: GET unix://localhost:80/containers/{container_id}/json: 404, body: {
    “message”: “No such container: {container_id}”
  1. An error related to a failed proxy request, potentially due to a prematurely closed connection:
ERROR 7801 --- [XNIO-1 I/O-2] io.undertow.proxy : UT005028: Proxy request to /proxy_endpoint/{session_id}/highcharts-x.y.z/modules/timeline.js failed
java.io.IOException: UT001000: Connection closed

In the ShinyProxy logs, we found additionally some reoccurring errors, which are (at least time-)independent to the “lost” containers (still, we have the suspicion they have the same root):

023-11-06 14:10:33.672 ERROR 7816 --- [pool-1-thread-13] e.o.containerproxy.service.ProxyService  : [user=user_id proxyId=proxy_id specId=spec_id] Failed to remove proxy


eu.openanalytics.containerproxy.ContainerProxyException: Failed to stop container

We also observed several Exception handling request to..., e.g.:

023-10-10 21:43:52.779 ERROR 7990 --- [XNIO-1 task-2] io.undertow.request                      : UT005023: Exception handling request to /proxy_endpoint/moin_static170rc3/favicon.ico

This error occurred with a range of other files (which are, by the way, not part of our app) as well, such as:


We have already double-checked the Docker and ShinyProxy configurations, found no significant resource constraints, and verified network settings. Nonetheless, the problem persists.

Has anyone experienced similar issues or could provide insights into what might be causing this problem? Any advice or suggestions would be greatly appreciated. Thank you in advance for your support! :slight_smile:

Best regards,

While waiting and hoping for an answer, I posted on SO as well

I am glad you reposted. I am having similar issues regarding UT005028 type errors. The issues I am trouble shooting, happen during startup. However, they are intermittent.

I’m not sure how to go about trouble shooting them, as they are happening in users browsers. Mine tend to be all related to DT::datatables content and downloading the css/js files not the same one each time. I suspect corrupted cookies and http problems like oversized headers. Maybe load balancer issues, or even issues in shiny iteslf handling https requests. I occasionally get these types of errors, and deleting the cookies seems to clear them up. Too many cookies? I looked at the har file for one of the users, and they have around one hundred and fifty SAML cookies.