[pbs-devel] [pve-devel] [RFC many v2 00/12] notifications: add support for webhook endpoints

[Lukas Wagner]

On  2024-07-17 17:34, Max Carrara wrote:
> On Fri Jul 12, 2024 at 1:27 PM CEST, Lukas Wagner wrote:
>> Sending as an RFC because I don't want this merged yet; that being
>> said, the feature should be mostly finished at this point, I'd
>> appreciate any reviews and feedback.
>>
>> This series adds support for webhook notification targets to PVE
>> and PBS.
>>
>> A webhook is a HTTP API route provided by a third-party service that
>> can be used to inform the third-party about an event. In our case,
>> we can easily interact with various third-party notification/messaging
>> systems and send PVE/PBS notifications via this service.
>> The changes were tested against ntfy.sh, Discord and Slack.
>>
>> The configuration of webhook targets allows one to configure:
>>   - The URL
>>   - The HTTP method (GET/POST/PUT)
>>   - HTTP Headers
>>   - Body
>>
>> One can use handlebar templating to inject notification text and metadata
>> in the url, headers and body.
>>
>> One challenge is the handling of sensitve tokens and other secrets.
>> Since the endpoint is completely generic, we cannot know in advance
>> whether the body/header/url contains sensitive values.
>> Thus we add 'secrets' which are stored in the protected config only
>> accessible by root (e.g. /etc/pve/priv/notifications.cfg). These
>> secrets are accessible in URLs/headers/body via templating:
>>
>>   Url: https://example.com/{{ secrets.token }}
>>
>> Secrets can only be set and updated, but never retrieved via the API.
>> In the UI, secrets are handled like other secret tokens/passwords.
>>
>> Bumps for PVE:
>>   - libpve-rs-perl needs proxmox-notify bumped
>>   - pve-manager needs bumped proxmox-widget-toolkit and libpve-rs-perl bumped
>>   - proxmox-mail-forward needs proxmox-notify bumped
>>
>> Bumps for PBS:
>>   - proxmox-backup needs proxmox-notify bumped
>>   - proxmox-mail-forward needs proxmox-notify bumped
> 
> Since this is an RFC, I mainly just did some proofreading; I haven't
> really spotted anything out of the ordinary, apart from a few *very
> small* things I commented on inline.
> 
> I like the overall idea of adding webhooks, so this looks pretty solid
> to me. At first I thought that this might be a bit of a niche use case,
> but I feel like it might actually be quite interesting for orgs that are
> e.g. on Slack: You could e.g. just "route" all notifications via a
> webhook to Slack, and Slack then sends a push notification to one's
> phone. The same can obviously done with other applications / services as
> well. So, pretty cool stuff :)
> 
> Not sure if this has been discussed somewhere already (off list etc.),
> but could you elaborate on why you don't want this merged yet? The
> patches look pretty solid to me, IMHO. Then again, I haven't really
> tested them yet due to all the required package bumps, so take this with
> a grain of salt.
> 
> If you want to have this RFC tested, I can of course give it a shot - do
> let me know if that's the case :)
> 

I posted this as an RFC because while I consider this as mostly finished,
it did not yet go through my own rigorous self-review/testing.
I had to switch to some other task and wanted to get this version out to get some
general feedback.

There are no changes planned unless I or somebody else discovers any issues,
so I'd very much welcome any testing :)

-- 
- Lukas