Fix basic alerting so that it... alerts.

Since adding the alerting I find that it doesn't work any more. I'm not sure why since I did test at the time. We're now using a newer terraform provider - maybe that's it, or perhaps the underlying api in gcloud has changed. Anyway, I believe that this works - it's quite hard to test without actually using it. At the time of writing the dev shib-metadata project uses this. See e.g https://console.cloud.google.com/monitoring/uptime?project=shib-metadata-devel-d10d66c7

See also https://gitlab.developers.cam.ac.uk/uis/devops/raven/shibboleth-metadata-deployment/-/issues/8 https://gitlab.developers.cam.ac.uk/uis/devops/tls-certificates/google-cloud-deploy/-/issues/8

approved this merge request

Merging without testing beyond the testing described by @pr414 in the comments since, in this case, it's pretty hard to test something which is quite so much spooky action at a distance. Happy to do so since we can easily revert/replace if necessary.

merged

mentioned in commit e35f4bc3

Yeah - as discussed elsewhere, it would be nice to get some basic testing for these terraform libraries. I'll make an issue.

can we tests as we did yesterday? forbidding traffic to staging cloud run and see if we get the alert.

yeah, I did that yesterday but with just me as the email recipient - I'll try again now that we have the devops email address.

So, the two apps using this shib-metadata and tlscerts don't seem to behave in the same way (one is working as intended, the other not), despite consuming the same config. I'll put the two relevant MR's back to WIP and the issues to rework and spend some more time figuring out what's going on.