Plugin not found on CentOS 7 and 8

[timn]

I have tried to install the plugin on CentOS 7. First, the encoding="utf-8" in setup.py must be removed, then the package could be installed with pip from the modified tarball. Certbot is version 1.7.0 which can be installed from Fedora EPEL for CentOS. I use this to renew HTTP-based certificates just fine. I then wanted to use certbot-external-auth to issue a wildcard cert with a DNS-01 challenge. CentOS 7 uses Python 2.7, as does the certbot package.

Running certbot plugins shows other plugins, but not the external-auth plugin. I have used strace -f -e trace=open certbot ... to see wihch Python modules are opened. All plugins open fine, also the external-auth plugin.py is opened. However, the plugin does not show up.

I suspected there might be problems with the old CentOS 7. I therefore also tried with CentOS 8 in a docker container docker run --rm -ti centos:8 /bin/bash. Inside the container I did:

yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
yum install -y certbot
pip-3 install certbot-ext-auth
certbot plugins

The output of the latter command shows standalone and webroot, but not external-auth.The debug log does not yield more info.

I have also tried installing certbot and certbot-ext-auth from pip within a CentOS 8 container (also requires to pip install future or an error that past could not be found occurs). This didn't work either, plugin still not shown.

Am I missing anything? Does the plugin need some adjustments for newer certbot versions?