Potential memory leak after upgrading to 3.0.1 from 2.0.0

What happened: After upgrading from grafana-image-renderer 2.0.0 to 3.0.1 we are seeing increased memory usage across some of our instances. Additionally the increase happens gradually over time, indicating possibly a memory leak.

Notes on the picture above:

• we have an instance of grafana-image-renderer per customer. Each line in the graph represents one instance
• all instances were upgraded around the same time. We are not seeing the issue across all instances. However this can be due to the fact, that we only use the image-renderer on one page and usage of that page might differ between customers

here is a more fine-grained chart of one of the instances

What you expected to happen: Memory consumption to be roughly the same as before the upgrade

How to reproduce it (as minimally and precisely as possible):

I am having a tough time reproducing this issue in a controlled environment. I have decided to try to explain what we are doing, please let me know if there is any additional info I can fetch to help you out.

First off, we are only doing one call to get a chart. The chart query is not too fancy and takes around 2 seconds to finish. Here is an example using curl

curl -w "@/tmp/curl-format.txt" -s '<<sanitized>>/render/d-solo/_eAFi6uWk/meshfed?refresh=1m&orgId=1&panelId=13&theme=light&width=1000&height=500&tz=Europe/Berlin' --user "${UNAME}:${PW}"

     time_namelookup:  0.001459s
        time_connect:  0.023928s
     time_appconnect:  0.071088s
    time_pretransfer:  0.071160s
       time_redirect:  0.000000s
  time_starttransfer:  2.251392s
                     -----------
          time_total:  2.251415s

I have already tried to manually put a high-load on the system calling the aforementioned command in a loop, but no indication of memory leaks, the renderer frees the memory after the load again, dropping consumption back to its idle state.

Anything else we need to know?:

Environment:

• Grafana Image Renderer version: 3.0.1
• Grafana version: v8.0.6
• Installed plugin or remote renderer service: // not sure what is meant here. We are running the standard docker image as a remote renderer service
• OS Grafana Image Renderer is installed on: alpine (we are running the standard docker image)

[SimonTheLeg]

Hi @AgnesToulet. Sounds good! I have tried it with 3.2.0 and the leak did not occur anymore. Thank you for your work!

[AgnesToulet]

@SimonTheLeg Version 3.1.0 is released. I’m closing this issue as it should be fixed by upgrading the plugin but feel free to open it again if this didn’t fix it.