bug#46961: Nginx and certbot cervices don't play well togther

[Carlo Zancanaro]

Hi Clément,

Thanks for taking the time to review my change. I've responded inline
below.

On Mon, Jan 29 2024, Clément Lassieur wrote:
> This is great, thank you!  I tested it, it worked.  Could you please
> just make sure lines fit within 80 columns?

Yep, no worries.

> Would it make sense now to run ‘update-certificates’ at end of the
> activation stuff?

We can't run it during activation, because nginx won't have started yet.
However, I am planning a follow-up to add a one-shot service to run
certbot after nginx starts. I'll see if I can add it to this series, but
if I run into any issues I'll leave it for later.

> And would it make sense to reload nginx after ‘update-certificates’ is
> run?

This would be a sensible default. There is an example in the manual of
configuring certbot to reload nginx, so this should be straightforward
to add.

> gnu/services/certbot.scm:203:26: warning: "subjectAltName=~{DNS:~a~^,~}": 
> unsupported format option ~{, use (ice-9 format) instead

Ha! I import (ice-9 format), but within the gexp (and then I don't use
it, whoops!). Must be a leftover from a previous iteration. I'll fix
this up.

>> +             ;; Due to the way certbot runs, we need to
>> +             ;; create the self-signed certificates in the
>> +             ;; archive folder and symlink them into the live
>> +             ;; folder. This mimics what certbot does well
>> +             ;; enough to make acquiring new certificates
>> +             ;; work.
>
> In another mail you say it doesn't work as well as you thought it did?
> What doesn't work?

This comment doesn't describe the code any more. In my first attempt I
was trying to generate certificates in /etc/letsencrypt/live/ and get
certbot to write over them when it ran. Unfortunately, it refused to do
so. I then tried writing to /etc/letsencrypt/archive/ and symlinking
into /etc/letsencrypt/live/ (which is what this comment describes), but
that also failed. Certbot refuses to write over any existing files when
fetching a certificate.

It looks like other acme clients might be happier to overwrite existing
files, but changing away from certbot seemed like more work than adding
a deploy hook to do what we need.

I'll follow up with a v2 of this patch when I get a chance.

Carlo