Add SSL Certificate Expiration Checks for HTTPS

[asreich]

What would you like to be added:

I would like there to be some default AlertRules generated for SSL Certificate Expiration Checks for HTTPS applications similar to what is described here.

Why is this needed:

Synthetic Monitoring is great and I can create these rules myself but it would be nice to have these baked in and get them for free with whatever HTTPS endpoints are added.

Additional context

If this already exists, I haven't been able to find an alert rule for it. Looking at making this for myself, it seems like the probe_ssl_earliest_cert_expiry metric is still generated for things that are Ignoring the SSL validation, so we'd need to somehow differentiate that.

[mem]

Thank you! We are actually working on this, but we don't have an ETA right now.

[asreich]

@mem Hello again, any updates on this possible feature?

[mem]

It should be available everywhere now.

[asreich]

@mem Thank you so much! 🥳 I haven't tried it out yet but I see it available as an option in the Synthetic Monitoring app now. If I find any bugs I'll file followups.