Comment 0 for bug 1843486

gss currently uses a shell wrapper to source Juju proxy settings from a certain file.

cat /usr/share/glance-simplestreams-sync/glance-simplestreams-sync.sh
#!/bin/bash
if [ -f /etc/juju-proxy.conf ]; then
    source /etc/juju-proxy.conf
elif [ -f /home/ubuntu/.juju-proxy ]; then
    source /home/ubuntu/.juju-proxy
fi
exec /usr/share/glance-simplestreams-sync/glance-simplestreams-sync.py

However, Juju only saves those files for legacy proxy settings:

Provisioning time
https://github.com/juju/juju/blob/juju-2.6.8/cloudconfig/userdatacfg_unix.go#L280-L286

Proxy updater on model proxy settings changes
https://github.com/juju/juju/blob/juju-2.6.8/worker/proxyupdater/proxyupdater.go#L186-L190
https://github.com/juju/juju/blob/juju-2.6.8/worker/proxyupdater/proxyupdater.go#L150-L157
https://github.com/juju/juju/blob/juju-2.6.8/worker/proxyupdater/proxyupdater.go#L101-L110

Therefore, the charm needs to be reworked to support juju-http-proxy, juju-https-proxy, juju-no-proxy.