[pve-devel] [PATCH proxmox 01/19] notify: switch to file-based templating system

[Lukas Wagner]

On  2024-04-19 10:14, Fiona Ebner wrote:
> Am 09.04.24 um 15:25 schrieb Lukas Wagner:
>> Instead of passing the template strings for subject and body when
>> constructing a notification, we pass only the name of a template.
>> When rendering the template, the name of the template is used to find
>> corresponding template files. For PVE, they are located at
>> /usr/share/proxmox-ve/templates/default. The `default` part is
>> the 'template namespace', which is a preparation for user-customizable
>> and/or translatable notifications.
>>
> 
> Is the plan to create different namespaces there ourselves or tell users
> they can put their custom templates there? In the latter case, I'm not
> sure /usr/share is the best place, rather than some place under /etc/

The idea would be to implement translations as other namespaces, e.g. `de` or `fr`
instead of `default`.
For user-overridable templates we would extend the implementation to search for a template
in another location first and then fall back to the templates provided by us in '/usr/share/...`
I have not made up my mind yet on where these user-provided templates would be located, either
in /usr/local/share/.... or somewhere in /etc (/etc/pve would ensure that we have the same templates
on all nodes, but I'm not sure if it is a good idea to put custom, user-created files in there...)

Combining both ideas: assuming that we want to render a fencing notification translated to German, assuming
that the user-override is in /usr/local/share:
  - First try to load /usr/local/share/proxmox-ve/templates/de/fencing.txt.hbs
  - If not found, try loading the shipped template at /usr/share/proxmox-ve/templates/de/...
  - If that one also does not exist, fall back to `default` namespace
    - first user-location
    - finally shipped template

> 
> Who adds the template files? I don't see a patch for proxmox-ve in this
> series. Does this series require some versioned breaks to some package?

The pve-manager and pve-ha-manager (for fencing notifications) patches add the templates.
I can't use `/usr/share/pve-manager` and `/usr/share/pve-ha-manager` because 
proxmox_notify needs to have a single base directory from where to load template files.
Maybe we should use some other base dir to avoid confusion with the `proxmox-ve` metapackage?

In terms of versions:
pve-{ha}-manager needs to pull in a bumped libpve-notify-perl
libpve-notify-perl needs to pull in bumped libpve-rs-perl/libproxmox-rs-perl
libpve-rs-perl needs to pull in bumped librust-proxmox-notify

I really wish the dep-chain was a bit easier, yet here we are.

-- 
- Lukas