caddy-reverse-proxy: loading png-images hangs for 5 seconds

[3gb1e]

Hi there,
I am running a caddy-reverse-proxy in a podman-container (v2.7.5) behind a podman-apache-container. Loading a png-image (less than 100kB; either inside html and as raw file) results in loading and displaying 12% of the image as fast as expected. Then it hangs for about 5 to 6 seconds, then the rest of the file will be loaded as fast as expected.
The issue occurs with all browsers, I tested with chromium, firefox, curl and wget.

The issue occurs only with png, not with jpg, gif or html-content.
Once the image lies in cache, loading time is as expected.

I think it's because of caddy as loading the png-image is
-> fast with development-apache-container (podman) directly connected
-> fast with production-apache-container (podman) directly connected to the port on server
-> slow as described with production-apache-container (podman) behind caddy-reverse-proxy running in a container (podman) on server

Somewhere I read about KeepAlive. I switched it off in apache and caddy: no success.

Caddyfile:

abc.de {
        reverse_proxy xyz-server:18002
}

www.abc.de {
        redir https://abc.de{uri}
}

Any hints would be appreciated!
Egbert

[mohammed90]

Thanks for your question, and we're thrilled that you're using Caddy! This looks a buffering problem rather than a bug report or feature request.

Since this issue tracker is reserved for actionable development items, I'm going to close this, but we have a community forum where more people will be exposed to your question, including people who may be more expert or experienced with the specific question you're facing. I hope you'll ask your question there, and thanks for understanding! Please don't forget to fill out the template.

[dmd]

Exact same issue here. @3gb1e did you find a solution? Posting here because the community forum thread is now locked with no resolution, and I wanted to reach you.

[3gb1e]

I posted the solution in the caddy community forum: https://caddy.community/t/slow-load-5-seconds-only-with-png-images/21730/12

TLDR: Use --network=host instead of the default --network=slirp4netns in podman. In order to use rootless podman you have to make caddy listen on unprivileged ports using the caddy directives http_port 8080 and https_port 4443.

[dmd]

Aha! That does work (in Docker, for me). Pity though because I definitely do not want to run my containers in net host mode.