why does the interface keep changing?

[stevemandl]

First the metrics were fetched with a call to the /search route, then that changed a couple years ago to a call to /variable. Now that doesn't work and we need to support calls to /metrics. Why does this keep changing? This is a breaking change: every time the data source middleware changes the way it works, all users have to update the back end to support the new route. I would suggest adding support for the older implementations, or stop changing the route the grafana server uses to search for metric names.

[simPod]

The datasource is still in v0.x where anything can change. BC changes are documented in release notes.