Smarter Notifications for --monitor-only Mode

[Turakar]

Is your feature request related to a problem? Please describe.
I use the --monitor-only flag together with Gotify notifications. This makes it very easy for me to monitor container updates on my personal home server. If a container has an update, Watchtower sends a Gotify notification every 10 minutes (my configured interval). This spamming is annoying and not very useful.

Describe the solution you'd like
Watchtower should not resend the same information. Instead, it should only notify of each update once.

Describe alternatives you've considered

• Implementing a filter in between, acting like a proxy.
• Lowering the check interval. This increases latency of notifications and does not really solve the problem.
• Enabling automatic updates. Seems too risky too me.

Additional remarks
If each update is only notified of once, the number of unread notifications in Gotify would be a helpful indicator for the amount of admin work necessary. Currently its more like a boolean flag.

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[simskij]

Hi, and welcome to the community! 🎉

I kind of get what you're after, but at the same time, that would break behavior that people might already rely on either in their monitoring or for being reminded there's still work left to do. If this suggestion was to enter watchtower, it would have to be as a non-default toggle, and as we don't persist any information between container instances, it would have to be repeated in case the watchtower container was recreated or restarted.

Does this sound reasonable? I kind of want other people to weigh in as well before we decide in any direction.

Best,
Simme

[Turakar]

Hi, thanks for your answer!

I was not aware of these consequences. Implementing it as a non-default toggle is no problem (I think). So I mainly see two problems:

• Loss of attention on updates where the corresponding notification is deleted.
• Persistence

The first problem could be solved by adding a second interval reminder. If Watchtower finds an update for a container it has already notified the admin of, but reminder passed since the last notification, it resends the notification. I, personally, would be fine without this solution, as Gotify makes it easy to manage notifications and delete them individually. I do understand, that this is not the case for Slack or Telegram and some others.

The persistence problem could be solved with either a SQL database or a JSON file. I would prefer the latter for simplicity as there seems to be no need for more advanced storage systems. The not so elegant solution would be to keep the state only in memory. This is acceptable in my opinion, as it is not a big problem if Watchtower notifies of an update multiple times - under the assumption that the Watchtower container is not removed frequently, e.g. only on updates.

[piksel]

Regarding persistence, I have been thinking about giving the shoutrrr CLI a role similar to this, where it would run in a separate container and do things like buffering notifications, bulking them, filtering duplicates and even send a notification if the consumer stops responding. It's just in a draft stage ATM, but it's issues like this that might justify it's existence.

[simskij]

Converting this to a discussion until we decide on something.