Pager Service
How to run the tests
You need either docker installed or ruby 3.2.2.
Run using ruby 3.2.2
Run bundle install and then rake test
Run using docker
Ensure the docker daemon is running.
Run ./docker-test.sh
Persistence guarantees
Pager delegates on repo and expects it to handle the different scenarios provided in the specification.
This means that repo.unhealthy will persist the unhealthy state to the database (and return true) unless
there is an ongoing alert. In such case, it will persist nothing and return false, but Pager doesn't care
about these details.
We can't check if there is an ongoing alert and then persist because that can lead to race conditions. So we
can handle this having an alerts table with a unique index over the service_id column, for example.
Calling repo.healthy would delete the record inserted in the previous step.